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850 owners with questions, read up! Expert advise here.
Repost from my friend and BRP Master Tech: Matt Leicester
This is a departure from my usual Facebook stuff, but I have tips for people who bought the new 2017 Ski-Doo Rev Gen 4 Summits, and we are trying to get the information to as many people as we can. So share away! Especially calling https://www.facebook.com/dave.norona/… and https://www.facebook.com/jeremy.mercier.7/…
This is a copy and paste of what I wrote that went to other Ski-Doo dealers, I will have to add a photo album and try to get the captions so they make sense, unfortunately the pictures did not copy in place.
Maximizing G4 Summit belt life
We have now had two good snow weekends in Colorado, and I have yet to hear of one of our Summit 850 models blowing a belt. Considering that this last weekend we had a couple of guys run out of gas at 30 something miles, I'm pretty sure the snow was plenty deep and the sleds were working hard! Since I have not been on an 850 out of break in yet, we are using the recommended high altitude settings, so in that respect our sleds should not be that different than what others are using.
We do, however, remove all of the acoustic panels under the hood and on the belt guard. I have been at one Ski-Doo dealer or another since 1986, and whenever Ski-Doo has installed parts that were kind of flimsy looking, easily removed, and installed strictly to meet sound requirements, we have removed those parts! On the 1985-1990 PRS chassis sleds, there was a corrugated piece of plastic with a metal push pin that the PDI bulletin said to install in the air intake. Um, if you did install that part, the sled ran so rich it would barely run! It got even better, in 1990 the Formula Mach 1 came with two holes about 1 1/2" in diameter in the airbox, with plastic caps in the holes and covered by screens held in place with screws. Same thing, if you did not remove those plugs and let the airbox breathe through the now open holes, you would need to drop the main jets about 50 points. So there is precedence for removing acoustic panels. We have removed the acoustic panels by the muffler since the XP chassis started, as well as cut around the tool box on the belt guard panel with absolutely no issues, those panels are there to meet strict sound regulations. I personally cannot tell the difference in sound between the panels installed or removed sound wise, but there is a huge difference in belt temperatures and in ease of installing and removing the belt guards! Obviously as a manufacturer, Ski-Doo cannot tell anyone, especially a dealer, to remove panels needed for sound compliance, but I have been doing just that for years with no ill effects.
For the G4, let's start with the belt guard. There is a large felt kind of panel covering the entire inside of the belt guard, once you remove the large panel, there is a horseshoe shaped piece of foam that can also be removed. I reinstall the four darts that hold the large panel in place after removing the panel just to plug the holes in the cooling cover. This picture is as the machine is delivered:
Belt guard with panel.jpg
Once you remove this piece by removing the four darts, you have this:
Belt guard horseshoe foam.jpg
There is also a small rectangular piece of foam on the back of the belt guard, just below the clip that retains the guard. to make removing and installing the belt guard a little easier, remove that piece of foam. And while on the subject of making dealing with the belt guard a little easier, I painted the front mounting plate with white engine enamel, it makes finding the slot for the front mount much easier:
White painted belt guard mount.jpg
The white paint certainly does not last like the black powder coating, so maybe some people will not like the scratches, but others will greatly appreciate seeing what they are doing a little better! Here is with the belt guard installed:
White painted mount installed.jpg
One last trick for the belt guard, and I just did this after the weekend so I will need to check belt temperatures again next week, is to drill a hole in line with the driven clutch. I used a 3 1/8" hole saw I have from the S chassis speedometer days, I think you could go as far as 3 1/2" before you run out of room by the recess for the spare belt. The hole is centered about 28 mm below the center of the raised section of the belt guard, and in line toward the lower protrusion around the raised section. The pilot hole for location:
Belt guard pilot hole.jpg
Finding the center of the raised area is easy enough, set a caliper to 47 mm and swing with the fixed point of the caliper on each of the three protrusions and the swinging end scribing an arc in the middle of the raised area. Where the three arcs intersect is the center of the raised area:
Belt guard finding center.jpg
The belt guard installed with the 3 1/8" hole drilled in the cover:
Belt guard installed.jpg
There are also five different acoustic panels that should be removed from under the hood. The large felt panel behind the belt guard and driven clutch is quite easy to remove with the top of the sled in place, as is the small panel on the right side that attaches to the coolant tank. Removing the panel on the coolant tank is a question of balance - I was removing that panel before we had snow and heard of coolant tanks breaking, I think perhaps I will leave the coolant tank panel in place now as it supports the coolant tank and is at the same time small enough I do not think it restricts airflow enough to worry about. The large felt panel is held in place by a single push pin, the right side panel is removed with an 8 mm socket. If you remove the top of the sled, you can take out more panels, improving air flow under the hood and to the clutches and also making it so you can see the spark plugs! The first picture is all the panels in place, with the top off the sled:
All panels installed.jpg
The panel in front of the large felt panel is held in place with one more push pin under the RAVE cable and one of the coil attaching screws on the oil tank. Remove the push pin and save it for your Spyders or SSV models that always need more push pins, but reinstall the T20 screw for the coil:
Front panel screw.jpg
The engine cover is a two piece part, the two pieces are held together by three T30 Torx screws that look like they may be stainless steel, but happily are magnetic if you drop one! I remove the oil tank side screw with a ball ended long T30 bit I got from our Cornwell Tools dealer:
Engine cover screws.jpg
Once those three screws are removed, you can remove the front engine cover by pulling up (Hard!) at the corners. The covers mount to the engine with grommets on ball studs attached to the head, if you pull at the grommets the cover will come up, but it does take a pretty hard pull. You can twist the front cover around clockwise and pull it out by the steering column, you do not need to remove any other parts like the exhaust or anything. I have not torn a cover yet, but even if that were to happen, no problem, you are throwing the covers away! Once the front cover is removed, the rear cover attaches only at the corner of the cylinder head closest to the driven clutch. Again, it takes a pretty solid pull to pop the cover from its mounting stud, but once off the mount, the rear cover is pretty easy to pull out of the engine compartment as the rear cover is much smaller than the front. Another advantage of removing the large felt panel, at least on electric start machines, is that you can connect a Battery Tender charging pigtail to the starter relay that was hidden by the panel and customers can charge their battery without needing to remove bags or the battery cover at the back of the gas tank. Once all of the acoustic panels are removed from under the hood, it starts to look like a snowmobile again:
All panels removed.jpg
When you are done, you should have a pile of parts left over like this:
Removed panels.jpg
After having one customer come in worried about hearing stories of blown belts before he had even picked up his sled, we now keep a set of these panels to show people how much airflow blocking parts we remove to improve air management under the hood, it seemed to make him relax a bit knowing we were proactive about belt cooling before the sled even went out. Also, the belt guard is easier to install and remove with the panels off the back side, and that big hole in the middle makes a great handle!
One last item to note, we have found that with the 26 mm pivot bolts the high altitude bulletin calls for at 10,000 feet altitude and the clickers on 5 we were seeing 8200 rpm and maybe more, even on the first tank of gas. With the clickers on 4, the peak rpm under load in deep snow was very close to the 8,000 rpm we were looking for, which should lower belt temperatures in itself. Once we get our two demo 850 Summits out of break in we will start playing with clutching a bit more, but the performance out of the box and set up to the altitude bulletin seems very good.
Note! I edited this post the morning after I wrote it, now that I have access to the machines in our shop with better lighting, I moved the hole in the belt guard slightly. The dimensions and pictures above look very good now that I could get back from the snowmobile and look with less of an angle. The idea of the hole in the belt guard centered on the driven clutch comes courtesy of the Maverick side by sides with the QRS driven - with the acoustic panels removed, cool air can be drawn in through the hole by the driven clutch acting as a fan and expelled as intended by the QRS clutch cooling cover.
Matt Leicester
Master Certified Tech, Ski-Doo, Sea-Doo PWC, Can-Am Off Road, Roadster
RPM Motorsports, Lakewood, Colorado
Added a share preview to this post.
Matt Leicester
22 minutes ago
This is a departure from my usual Facebook stuff, but I have tips for people who bought the new 2017 Ski-Doo Rev Gen 4 Summits, and we are trying to get the information to as many people as we can. So share away! Especially calling https://www.facebook.com/dave.norona/… and https://www.facebook.com/jeremy.mercier.7/…
This is a copy and paste of what I wrote that went to other Ski-Doo dealers, I will have to add a photo album and try to get the captions so they make sense, unfortunately the pictures did not copy in place. I made an album titled Rev Gen 4 acoustic panels, it was supposed to be attached to this post but that does not seem to be happening! So look for it separately...
Maximizing G4 Summit belt life
We have now had two good snow weekends in Colorado, and I have yet to hear of one of our Summit 850 models blowing a belt. Considering that this last weekend we had a couple of guys run out of gas at 30 something miles, I'm pretty sure the snow was plenty deep and the sleds were working hard! Since I have not been on an 850 out of break in yet, we are using the recommended high altitude settings, so in that respect our sleds should not be that different than what others are using.
We do, however, remove all of the acoustic panels under the hood and on the belt guard. I have been at one Ski-Doo dealer or another since 1986, and whenever Ski-Doo has installed parts that were kind of flimsy looking, easily removed, and installed strictly to meet sound requirements, we have removed those parts! On the 1985-1990 PRS chassis sleds, there was a corrugated piece of plastic with a metal push pin that the PDI bulletin said to install in the air intake. Um, if you did install that part, the sled ran so rich it would barely run! It got even better, in 1990 the Formula Mach 1 came with two holes about 1 1/2" in diameter in the airbox, with plastic caps in the holes and covered by screens held in place with screws. Same thing, if you did not remove those plugs and let the airbox breathe through the now open holes, you would need to drop the main jets about 50 points. So there is precedence for removing acoustic panels. We have removed the acoustic panels by the muffler since the XP chassis started, as well as cut around the tool box on the belt guard panel with absolutely no issues, those panels are there to meet strict sound regulations. I personally cannot tell the difference in sound between the panels installed or removed sound wise, but there is a huge difference in belt temperatures and in ease of installing and removing the belt guards! Obviously as a manufacturer, Ski-Doo cannot tell anyone, especially a dealer, to remove panels needed for sound compliance, but I have been doing just that for years with no ill effects.
For the G4, let's start with the belt guard. There is a large felt kind of panel covering the entire inside of the belt guard, once you remove the large panel, there is a horseshoe shaped piece of foam that can also be removed. I reinstall the four darts that hold the large panel in place after removing the panel just to plug the holes in the cooling cover. This picture is as the machine is delivered:
Belt guard with panel.jpg
Once you remove this piece by removing the four darts, you have this:
Belt guard horseshoe foam.jpg
There is also a small rectangular piece of foam on the back of the belt guard, just below the clip that retains the guard. to make removing and installing the belt guard a little easier, remove that piece of foam. And while on the subject of making dealing with the belt guard a little easier, I painted the front mounting plate with white engine enamel, it makes finding the slot for the front mount much easier:
White painted belt guard mount.jpg
The white paint certainly does not last like the black powder coating, so maybe some people will not like the scratches, but others will greatly appreciate seeing what they are doing a little better! Here is with the belt guard installed:
White painted mount installed.jpg
One last trick for the belt guard, and I just did this after the weekend so I will need to check belt temperatures again next week, is to drill a hole in line with the driven clutch. I used a 3 1/8" hole saw I have from the S chassis speedometer days, I think you could go as far as 3 1/2" before you run out of room by the recess for the spare belt. The hole is centered about 28 mm below the center of the raised section of the belt guard, and in line toward the lower protrusion around the raised section. The pilot hole for location:
Belt guard pilot hole.jpg
Finding the center of the raised area is easy enough, set a caliper to 47 mm and swing with the fixed point of the caliper on each of the three protrusions and the swinging end scribing an arc in the middle of the raised area. Where the three arcs intersect is the center of the raised area:
Belt guard finding center.jpg
The belt guard installed with the 3 1/8" hole drilled in the cover:
Belt guard installed.jpg
There are also five different acoustic panels that should be removed from under the hood. The large felt panel behind the belt guard and driven clutch is quite easy to remove with the top of the sled in place, as is the small panel on the right side that attaches to the coolant tank. Removing the panel on the coolant tank is a question of balance - I was removing that panel before we had snow and heard of coolant tanks breaking, I think perhaps I will leave the coolant tank panel in place now as it supports the coolant tank and is at the same time small enough I do not think it restricts airflow enough to worry about. The large felt panel is held in place by a single push pin, the right side panel is removed with an 8 mm socket. If you remove the top of the sled, you can take out more panels, improving air flow under the hood and to the clutches and also making it so you can see the spark plugs! The first picture is all the panels in place, with the top off the sled:
All panels installed.jpg
The panel in front of the large felt panel is held in place with one more push pin under the RAVE cable and one of the coil attaching screws on the oil tank. Remove the push pin and save it for your Spyders or SSV models that always need more push pins, but reinstall the T20 screw for the coil:
Front panel screw.jpg
The engine cover is a two piece part, the two pieces are held together by three T30 Torx screws that look like they may be stainless steel, but happily are magnetic if you drop one! I remove the oil tank side screw with a ball ended long T30 bit I got from our Cornwell Tools dealer:
Engine cover screws.jpg
Once those three screws are removed, you can remove the front engine cover by pulling up (Hard!) at the corners. The covers mount to the engine with grommets on ball studs attached to the head, if you pull at the grommets the cover will come up, but it does take a pretty hard pull. You can twist the front cover around clockwise and pull it out by the steering column, you do not need to remove any other parts like the exhaust or anything. I have not torn a cover yet, but even if that were to happen, no problem, you are throwing the covers away! Once the front cover is removed, the rear cover attaches only at the corner of the cylinder head closest to the driven clutch. Again, it takes a pretty solid pull to pop the cover from its mounting stud, but once off the mount, the rear cover is pretty easy to pull out of the engine compartment as the rear cover is much smaller than the front. Another advantage of removing the large felt panel, at least on electric start machines, is that you can connect a Battery Tender charging pigtail to the starter relay that was hidden by the panel and customers can charge their battery without needing to remove bags or the battery cover at the back of the gas tank. Once all of the acoustic panels are removed from under the hood, it starts to look like a snowmobile again:
All panels removed.jpg
When you are done, you should have a pile of parts left over like this:
Removed panels.jpg
After having one customer come in worried about hearing stories of blown belts before he had even picked up his sled, we now keep a set of these panels to show people how much airflow blocking parts we remove to improve air management under the hood, it seemed to make him relax a bit knowing we were proactive about belt cooling before the sled even went out. Also, the belt guard is easier to install and remove with the panels off the back side, and that big hole in the middle makes a great handle!
One last item to note, we have found that with the 26 mm pivot bolts the high altitude bulletin calls for at 10,000 feet altitude and the clickers on 5 we were seeing 8200 rpm and maybe more, even on the first tank of gas. With the clickers on 4, the peak rpm under load in deep snow was very close to the 8,000 rpm we were looking for, which should lower belt temperatures in itself. Once we get our two demo 850 Summits out of break in we will start playing with clutching a bit more, but the performance out of the box and set up to the altitude bulletin seems very good.
Note! I edited this post the morning after I wrote it, now that I have access to the machines in our shop with better lighting, I moved the hole in the belt guard slightly. The dimensions and pictures above look very good now that I could get back from the snowmobile and look with less of an angle. The idea of the hole in the belt guard centered on the driven clutch comes courtesy of the Maverick side by sides with the QRS driven - with the acoustic panels removed, cool air can be drawn in through the hole by the driven clutch acting as a fan and expelled as intended by the QRS clutch cooling cover.
Matt Leicester
Master Certified Tech, Ski-Doo, Sea-Doo PWC, Can-Am Off Road, Roadster
RPM Motorsports, Lakewood, Colorado
This is visible to anyone who can see this post.
Repost from my friend and BRP Master Tech: Matt Leicester
This is a departure from my usual Facebook stuff, but I have tips for people who bought the new 2017 Ski-Doo Rev Gen 4 Summits, and we are trying to get the information to as many people as we can. So share away! Especially calling https://www.facebook.com/dave.norona/… and https://www.facebook.com/jeremy.mercier.7/…
This is a copy and paste of what I wrote that went to other Ski-Doo dealers, I will have to add a photo album and try to get the captions so they make sense, unfortunately the pictures did not copy in place.
Maximizing G4 Summit belt life
We have now had two good snow weekends in Colorado, and I have yet to hear of one of our Summit 850 models blowing a belt. Considering that this last weekend we had a couple of guys run out of gas at 30 something miles, I'm pretty sure the snow was plenty deep and the sleds were working hard! Since I have not been on an 850 out of break in yet, we are using the recommended high altitude settings, so in that respect our sleds should not be that different than what others are using.
We do, however, remove all of the acoustic panels under the hood and on the belt guard. I have been at one Ski-Doo dealer or another since 1986, and whenever Ski-Doo has installed parts that were kind of flimsy looking, easily removed, and installed strictly to meet sound requirements, we have removed those parts! On the 1985-1990 PRS chassis sleds, there was a corrugated piece of plastic with a metal push pin that the PDI bulletin said to install in the air intake. Um, if you did install that part, the sled ran so rich it would barely run! It got even better, in 1990 the Formula Mach 1 came with two holes about 1 1/2" in diameter in the airbox, with plastic caps in the holes and covered by screens held in place with screws. Same thing, if you did not remove those plugs and let the airbox breathe through the now open holes, you would need to drop the main jets about 50 points. So there is precedence for removing acoustic panels. We have removed the acoustic panels by the muffler since the XP chassis started, as well as cut around the tool box on the belt guard panel with absolutely no issues, those panels are there to meet strict sound regulations. I personally cannot tell the difference in sound between the panels installed or removed sound wise, but there is a huge difference in belt temperatures and in ease of installing and removing the belt guards! Obviously as a manufacturer, Ski-Doo cannot tell anyone, especially a dealer, to remove panels needed for sound compliance, but I have been doing just that for years with no ill effects.
For the G4, let's start with the belt guard. There is a large felt kind of panel covering the entire inside of the belt guard, once you remove the large panel, there is a horseshoe shaped piece of foam that can also be removed. I reinstall the four darts that hold the large panel in place after removing the panel just to plug the holes in the cooling cover. This picture is as the machine is delivered:
Belt guard with panel.jpg
Once you remove this piece by removing the four darts, you have this:
Belt guard horseshoe foam.jpg
There is also a small rectangular piece of foam on the back of the belt guard, just below the clip that retains the guard. to make removing and installing the belt guard a little easier, remove that piece of foam. And while on the subject of making dealing with the belt guard a little easier, I painted the front mounting plate with white engine enamel, it makes finding the slot for the front mount much easier:
White painted belt guard mount.jpg
The white paint certainly does not last like the black powder coating, so maybe some people will not like the scratches, but others will greatly appreciate seeing what they are doing a little better! Here is with the belt guard installed:
White painted mount installed.jpg
One last trick for the belt guard, and I just did this after the weekend so I will need to check belt temperatures again next week, is to drill a hole in line with the driven clutch. I used a 3 1/8" hole saw I have from the S chassis speedometer days, I think you could go as far as 3 1/2" before you run out of room by the recess for the spare belt. The hole is centered about 28 mm below the center of the raised section of the belt guard, and in line toward the lower protrusion around the raised section. The pilot hole for location:
Belt guard pilot hole.jpg
Finding the center of the raised area is easy enough, set a caliper to 47 mm and swing with the fixed point of the caliper on each of the three protrusions and the swinging end scribing an arc in the middle of the raised area. Where the three arcs intersect is the center of the raised area:
Belt guard finding center.jpg
The belt guard installed with the 3 1/8" hole drilled in the cover:
Belt guard installed.jpg
There are also five different acoustic panels that should be removed from under the hood. The large felt panel behind the belt guard and driven clutch is quite easy to remove with the top of the sled in place, as is the small panel on the right side that attaches to the coolant tank. Removing the panel on the coolant tank is a question of balance - I was removing that panel before we had snow and heard of coolant tanks breaking, I think perhaps I will leave the coolant tank panel in place now as it supports the coolant tank and is at the same time small enough I do not think it restricts airflow enough to worry about. The large felt panel is held in place by a single push pin, the right side panel is removed with an 8 mm socket. If you remove the top of the sled, you can take out more panels, improving air flow under the hood and to the clutches and also making it so you can see the spark plugs! The first picture is all the panels in place, with the top off the sled:
All panels installed.jpg
The panel in front of the large felt panel is held in place with one more push pin under the RAVE cable and one of the coil attaching screws on the oil tank. Remove the push pin and save it for your Spyders or SSV models that always need more push pins, but reinstall the T20 screw for the coil:
Front panel screw.jpg
The engine cover is a two piece part, the two pieces are held together by three T30 Torx screws that look like they may be stainless steel, but happily are magnetic if you drop one! I remove the oil tank side screw with a ball ended long T30 bit I got from our Cornwell Tools dealer:
Engine cover screws.jpg
Once those three screws are removed, you can remove the front engine cover by pulling up (Hard!) at the corners. The covers mount to the engine with grommets on ball studs attached to the head, if you pull at the grommets the cover will come up, but it does take a pretty hard pull. You can twist the front cover around clockwise and pull it out by the steering column, you do not need to remove any other parts like the exhaust or anything. I have not torn a cover yet, but even if that were to happen, no problem, you are throwing the covers away! Once the front cover is removed, the rear cover attaches only at the corner of the cylinder head closest to the driven clutch. Again, it takes a pretty solid pull to pop the cover from its mounting stud, but once off the mount, the rear cover is pretty easy to pull out of the engine compartment as the rear cover is much smaller than the front. Another advantage of removing the large felt panel, at least on electric start machines, is that you can connect a Battery Tender charging pigtail to the starter relay that was hidden by the panel and customers can charge their battery without needing to remove bags or the battery cover at the back of the gas tank. Once all of the acoustic panels are removed from under the hood, it starts to look like a snowmobile again:
All panels removed.jpg
When you are done, you should have a pile of parts left over like this:
Removed panels.jpg
After having one customer come in worried about hearing stories of blown belts before he had even picked up his sled, we now keep a set of these panels to show people how much airflow blocking parts we remove to improve air management under the hood, it seemed to make him relax a bit knowing we were proactive about belt cooling before the sled even went out. Also, the belt guard is easier to install and remove with the panels off the back side, and that big hole in the middle makes a great handle!
One last item to note, we have found that with the 26 mm pivot bolts the high altitude bulletin calls for at 10,000 feet altitude and the clickers on 5 we were seeing 8200 rpm and maybe more, even on the first tank of gas. With the clickers on 4, the peak rpm under load in deep snow was very close to the 8,000 rpm we were looking for, which should lower belt temperatures in itself. Once we get our two demo 850 Summits out of break in we will start playing with clutching a bit more, but the performance out of the box and set up to the altitude bulletin seems very good.
Note! I edited this post the morning after I wrote it, now that I have access to the machines in our shop with better lighting, I moved the hole in the belt guard slightly. The dimensions and pictures above look very good now that I could get back from the snowmobile and look with less of an angle. The idea of the hole in the belt guard centered on the driven clutch comes courtesy of the Maverick side by sides with the QRS driven - with the acoustic panels removed, cool air can be drawn in through the hole by the driven clutch acting as a fan and expelled as intended by the QRS clutch cooling cover.
Matt Leicester
Master Certified Tech, Ski-Doo, Sea-Doo PWC, Can-Am Off Road, Roadster
RPM Motorsports, Lakewood, Colorado
Added a share preview to this post.
Matt Leicester
22 minutes ago
This is a departure from my usual Facebook stuff, but I have tips for people who bought the new 2017 Ski-Doo Rev Gen 4 Summits, and we are trying to get the information to as many people as we can. So share away! Especially calling https://www.facebook.com/dave.norona/… and https://www.facebook.com/jeremy.mercier.7/…
This is a copy and paste of what I wrote that went to other Ski-Doo dealers, I will have to add a photo album and try to get the captions so they make sense, unfortunately the pictures did not copy in place. I made an album titled Rev Gen 4 acoustic panels, it was supposed to be attached to this post but that does not seem to be happening! So look for it separately...
Maximizing G4 Summit belt life
We have now had two good snow weekends in Colorado, and I have yet to hear of one of our Summit 850 models blowing a belt. Considering that this last weekend we had a couple of guys run out of gas at 30 something miles, I'm pretty sure the snow was plenty deep and the sleds were working hard! Since I have not been on an 850 out of break in yet, we are using the recommended high altitude settings, so in that respect our sleds should not be that different than what others are using.
We do, however, remove all of the acoustic panels under the hood and on the belt guard. I have been at one Ski-Doo dealer or another since 1986, and whenever Ski-Doo has installed parts that were kind of flimsy looking, easily removed, and installed strictly to meet sound requirements, we have removed those parts! On the 1985-1990 PRS chassis sleds, there was a corrugated piece of plastic with a metal push pin that the PDI bulletin said to install in the air intake. Um, if you did install that part, the sled ran so rich it would barely run! It got even better, in 1990 the Formula Mach 1 came with two holes about 1 1/2" in diameter in the airbox, with plastic caps in the holes and covered by screens held in place with screws. Same thing, if you did not remove those plugs and let the airbox breathe through the now open holes, you would need to drop the main jets about 50 points. So there is precedence for removing acoustic panels. We have removed the acoustic panels by the muffler since the XP chassis started, as well as cut around the tool box on the belt guard panel with absolutely no issues, those panels are there to meet strict sound regulations. I personally cannot tell the difference in sound between the panels installed or removed sound wise, but there is a huge difference in belt temperatures and in ease of installing and removing the belt guards! Obviously as a manufacturer, Ski-Doo cannot tell anyone, especially a dealer, to remove panels needed for sound compliance, but I have been doing just that for years with no ill effects.
For the G4, let's start with the belt guard. There is a large felt kind of panel covering the entire inside of the belt guard, once you remove the large panel, there is a horseshoe shaped piece of foam that can also be removed. I reinstall the four darts that hold the large panel in place after removing the panel just to plug the holes in the cooling cover. This picture is as the machine is delivered:
Belt guard with panel.jpg
Once you remove this piece by removing the four darts, you have this:
Belt guard horseshoe foam.jpg
There is also a small rectangular piece of foam on the back of the belt guard, just below the clip that retains the guard. to make removing and installing the belt guard a little easier, remove that piece of foam. And while on the subject of making dealing with the belt guard a little easier, I painted the front mounting plate with white engine enamel, it makes finding the slot for the front mount much easier:
White painted belt guard mount.jpg
The white paint certainly does not last like the black powder coating, so maybe some people will not like the scratches, but others will greatly appreciate seeing what they are doing a little better! Here is with the belt guard installed:
White painted mount installed.jpg
One last trick for the belt guard, and I just did this after the weekend so I will need to check belt temperatures again next week, is to drill a hole in line with the driven clutch. I used a 3 1/8" hole saw I have from the S chassis speedometer days, I think you could go as far as 3 1/2" before you run out of room by the recess for the spare belt. The hole is centered about 28 mm below the center of the raised section of the belt guard, and in line toward the lower protrusion around the raised section. The pilot hole for location:
Belt guard pilot hole.jpg
Finding the center of the raised area is easy enough, set a caliper to 47 mm and swing with the fixed point of the caliper on each of the three protrusions and the swinging end scribing an arc in the middle of the raised area. Where the three arcs intersect is the center of the raised area:
Belt guard finding center.jpg
The belt guard installed with the 3 1/8" hole drilled in the cover:
Belt guard installed.jpg
There are also five different acoustic panels that should be removed from under the hood. The large felt panel behind the belt guard and driven clutch is quite easy to remove with the top of the sled in place, as is the small panel on the right side that attaches to the coolant tank. Removing the panel on the coolant tank is a question of balance - I was removing that panel before we had snow and heard of coolant tanks breaking, I think perhaps I will leave the coolant tank panel in place now as it supports the coolant tank and is at the same time small enough I do not think it restricts airflow enough to worry about. The large felt panel is held in place by a single push pin, the right side panel is removed with an 8 mm socket. If you remove the top of the sled, you can take out more panels, improving air flow under the hood and to the clutches and also making it so you can see the spark plugs! The first picture is all the panels in place, with the top off the sled:
All panels installed.jpg
The panel in front of the large felt panel is held in place with one more push pin under the RAVE cable and one of the coil attaching screws on the oil tank. Remove the push pin and save it for your Spyders or SSV models that always need more push pins, but reinstall the T20 screw for the coil:
Front panel screw.jpg
The engine cover is a two piece part, the two pieces are held together by three T30 Torx screws that look like they may be stainless steel, but happily are magnetic if you drop one! I remove the oil tank side screw with a ball ended long T30 bit I got from our Cornwell Tools dealer:
Engine cover screws.jpg
Once those three screws are removed, you can remove the front engine cover by pulling up (Hard!) at the corners. The covers mount to the engine with grommets on ball studs attached to the head, if you pull at the grommets the cover will come up, but it does take a pretty hard pull. You can twist the front cover around clockwise and pull it out by the steering column, you do not need to remove any other parts like the exhaust or anything. I have not torn a cover yet, but even if that were to happen, no problem, you are throwing the covers away! Once the front cover is removed, the rear cover attaches only at the corner of the cylinder head closest to the driven clutch. Again, it takes a pretty solid pull to pop the cover from its mounting stud, but once off the mount, the rear cover is pretty easy to pull out of the engine compartment as the rear cover is much smaller than the front. Another advantage of removing the large felt panel, at least on electric start machines, is that you can connect a Battery Tender charging pigtail to the starter relay that was hidden by the panel and customers can charge their battery without needing to remove bags or the battery cover at the back of the gas tank. Once all of the acoustic panels are removed from under the hood, it starts to look like a snowmobile again:
All panels removed.jpg
When you are done, you should have a pile of parts left over like this:
Removed panels.jpg
After having one customer come in worried about hearing stories of blown belts before he had even picked up his sled, we now keep a set of these panels to show people how much airflow blocking parts we remove to improve air management under the hood, it seemed to make him relax a bit knowing we were proactive about belt cooling before the sled even went out. Also, the belt guard is easier to install and remove with the panels off the back side, and that big hole in the middle makes a great handle!
One last item to note, we have found that with the 26 mm pivot bolts the high altitude bulletin calls for at 10,000 feet altitude and the clickers on 5 we were seeing 8200 rpm and maybe more, even on the first tank of gas. With the clickers on 4, the peak rpm under load in deep snow was very close to the 8,000 rpm we were looking for, which should lower belt temperatures in itself. Once we get our two demo 850 Summits out of break in we will start playing with clutching a bit more, but the performance out of the box and set up to the altitude bulletin seems very good.
Note! I edited this post the morning after I wrote it, now that I have access to the machines in our shop with better lighting, I moved the hole in the belt guard slightly. The dimensions and pictures above look very good now that I could get back from the snowmobile and look with less of an angle. The idea of the hole in the belt guard centered on the driven clutch comes courtesy of the Maverick side by sides with the QRS driven - with the acoustic panels removed, cool air can be drawn in through the hole by the driven clutch acting as a fan and expelled as intended by the QRS clutch cooling cover.
Matt Leicester
Master Certified Tech, Ski-Doo, Sea-Doo PWC, Can-Am Off Road, Roadster
RPM Motorsports, Lakewood, Colorado
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