stock 175 need more gearing, top of primary

[fredw]

Been checking pdrive on the hill at 6500’, was surprised to see I’m running to top of primary, basically out of gear and maxed top end speed..50mph

maybe why I am seeing surging rpm from 8-8200rpm on gauge

i also see they only running a 40 degree helix on the 175 and it sure seams shallow you would think, compared to other B.B. in past

did a long pull and seen primary temps hit over 104c/225f on top of primary were belt was running.. I think this sled from past exsperince should be geard up at least one tooth on top sprocket..

whats others feel?? Sled is completely stock with 3 percent breakin left, have 2.5 grams added to pivot bolt since 50percent breakin..

 

[snochuk]

Been checking pdrive on the hill at 6500’, was surprised to see I’m running to top of primary, basically out of gear and maxed top end speed..50mph

maybe why I am seeing surging rpm from 8-8200rpm on gauge

i also see they only running a 40 degree helix on the 175 and it sure seams shallow you would think, compared to other B.B. in past

did a long pull and seen primary temps hit over 104c/225f on top of primary were belt was running.. I think this sled from past exsperince should be geard up at least one tooth on top sprocket..

whats others feel?? Sled is completely stock with 3 percent breakin left, have 2.5 grams added to pivot bolt since 50percent breakin..

You need to engage Dagg44- he is the man wen it comes to clutching.
Send him a PM.

 

[sick1]

Move your weight to the tip of the ramp. Need more weight on top. Slipping the belt in primary..

 

[Caper11]

Been checking pdrive on the hill at 6500’, was surprised to see I’m running to top of primary, basically out of gear and maxed top end speed..50mph

maybe why I am seeing surging rpm from 8-8200rpm on gauge

i also see they only running a 40 degree helix on the 175 and it sure seams shallow you would think, compared to other B.B. in past

did a long pull and seen primary temps hit over 104c/225f on top of primary were belt was running.. I think this sled from past exsperince should be geard up at least one tooth on top sprocket..

whats others feel?? Sled is completely stock with 3 percent breakin left, have 2.5 grams added to pivot bolt since 50percent breakin..

Yep, that helix is not doing the 850 any justice. It really didnt help the 800etec IMO.

Where is the belt tension adjusted to? You should see the cord on a 850, dont adjust it like a xm.

 

[fredw]

Had a good conversation with Joey from I backshift, he's one of the best if not the best with brp clutching.. Before I was into describing my problem More than a minute he already new of the problem, it's charterisics and what was needed to fix problem, he sure is welcome to share his wisdom on here, he says he has lots of good info on his website blog under G4 pdrive, he is running hard getting kits that work out the door, and this G4 is keeping him real busy..

first off stock gearing is good for 76mph on a 1 to 1 ratio which is more than needed for the G4 175.. This is almost good enough for turbo sleds if the rest is fixed correctly!!

he says if I'm only seeing 50mph on a hard pull and gearing is good for 76mph and belt is top in primary, it's very easy to find out what's wrong.. Had to think about it for a bit and it came to me..

belt has has to be slipping in secondary at bottom of sheives with least side surface area it's running on.. He's been seeing this lots and there is only two remedies.. First is to go to less helix for slower up shift or increase secondary belt spring tension with stiffer spring.. He highly recommends the latter one.. With so much snow load for mountain riding, large tracks and a strong motor, the secondary needs lots of squease to prevent slipping and heating of clutches and belt..

another gain of more squease will be that belt will now be able to run not as far up primary and not as far down secondary utilizing more surface area and allowing for a much cooler belt, less pealing of belt on cooling fins

he had me look at the lower secondary sheives and he was exactly correct, with heavy rubber deposits from belt slipping and above a dark shoe polish finish where it had extra heat added.. He said guys are reporting over 300f and belts don't last long, last year on 17s there was no cooling fins on secondary and this just happened that much quicker than this year..

he says many guys are telling you to drop secondary spring pressure and this just makes problem worse, or add more pin weight and this just makes it happen quicker.. Problem stands with secondary spring..

also has found problems with primary springs and that's a entire another issue to deal with latter, he's working on some ramps for turbo sleds and hoped to get them out soon


once again thank you Joey and can't wait for your arms.. Problem solved, and no need to gear up

 

[fredw]

Well I swapped out helix and secondary spring today for a black 157/303 spring and installed a shockwave helix to see how much I can pull, few buddies have tried this and are able to pull up to 46 degrees after making them not so revive and give some speed back to them down low, since stock helix is only 40 degrees now..was going to up top sprocket but decided to one step at a time.. Stock gearing is 21/53.. Once we get this figured out give it a try and then onto Sibler install

also added a total of 2.5 grams to each arm in primary now..

time to ride

 

[skegpro]

I'm following you, makes sense.

 

[fynnigan]

Well I swapped out helix and secondary spring today for a black 157/303 spring and installed a shockwave helix to see how much I can pull, few buddies have tried this and are able to pull up to 46 degrees after making them not so revive and give some speed back to them down low, since stock helix is only 40 degrees now..was going to up top sprocket but decided to one step at a time.. Stock gearing is 21/53.. Once we get this figured out give it a try and then onto Sibler install

also added a total of 2.5 grams to each arm in primary now..

time to ride

Tried this setup on my 18 165 ,didn’t work to good on mine. Went with a straight 45 and black spring in the secondary and some weight in the primary , tested it and the heat loss that was gained in the primary moved to the secondary. So went back to Aaen”s clutching manual and of the basics I forgot about is “the steeper the angle on the helix ,the less the squeeze on the belt . Mine had black tracks on th secondary . Let us know how it turns out

 

[dragonweld28]

Im not trying to hack this skidoo tread at all. I have been trying to clutch my axys 174 for 2 years now. I made little adjustments each ride and spoken to lots of guys with great info. I was reading all of your input Fred and what i have found is its these super hard belts that giving mountains sleds clutching problems. This doesn't mean I'm right but the set up i have found now sure works well and has almost no clutch heat. Let me explain.
These super hard belts require lots of primary squeeze and secondary squeeze to keep them from slipping. So, to offset the stiff springs we are now adding weight and steep helix angles to still get the sleds to pull hard and get OK track speeds. effectively we have now created a clutching set up that is fighting these stiffs springs and steep angles.
I have gone to lower gearing, softer spring and shallow helix angles with a softer Carlisle 809 belt. This belt has been key to making this set up work. I no longer need stiff springs to hold the belt on the secondary and the soft spring on the primary allows me to have strong squeeze with out extra cam weight. This has got me to the best track speed yet and after 30 min of continuous hard riding i can put my hand on the clutches and there warm. I was very surprised. Traditionally i know skidoo uses stiffer springs than polaris but i though this would help with your clutching issues on the new 175. This is the exact set up I'm running. The best track speeds i have gotten are 46 mph.

Gearing is 29/69 belt drive with 7 tooth 3" pitch drivers. Final gear ratio is 2.58. 64 gram EPI belly buster weights and a black/silver primary spring (120/300). The secondary is a 54-36.36 helix with 2 derlin washers and a red/green (120/220) secondary spring. I found the straight angles helix doesn't work the well for bottom end pull.

 

[fredw]

Put one day on the snow now with the shockwave 4 turns out and black secondary spring, 2.5 grams on each arm, rode Revy and heavy snow.. Rpm was glued on 7900 like it should be, even the max rpm now works like it should and only seen a max of 8100 the odd time, before it was 8400'evey time I looked..

sled just is is so much quicker I feel than before the change from seat of the pants, motor just sounds different from working it much harder, also had great backshift. Every time... helix works out now to around 47 degrees from the stock 40 and no more slipping belt, or rubber deposits on secondary..

I feel this is a very good clutching change for 7000' and gives a huge advantage over a stock G4, with much less belt heat and premature belt ware..

 

[fredw]

Put another day on sled this weekend and acceration is really picked up from stock, pulled 47 degrees all day and backshift good, snow was not deep, but each pull we did do, you could put hand on both primary and secondary.. Belt loving life