2015 M8000 Limited - Bent Tunnel Issues

[Vosh]

I have a question that I hope the forum can help me figure out.... I have a 2015 M8000 limited 153 track with approx. 2200 kms - I've owned since new and am old (50yrs) and a mediocre rider. I don't jump or abuse my machine in any way. I do go to the mountains a lot. Here's the list of upgrades that have all been done by my dealer: Upgraded shocks to raptor front and rear, upgraded running boards to proclimb, 2016 front end, skis,there's more, but its not pertinent to my issue. I noticed in November (prior to first ride this season) that both sides of my tunnel at the upper supports were starting to bow out (no wrinkles) - nothing major, but I weigh approx. 240lbs and thought the issue was because the stock Fox 2 air shock was bottoming out at 140lbs pressure all the time creating a lot of stress. I then changed out the rear shock to a raptor and adjusted the spring tension to where I had full movement of the suspension, but did not bottom out. However, I was riding this past weekend with my dealer (riding buddy) and noticed near the end of a ride (was rolling the machine over to get unstuck) that the issue of "bowing out" was back. This time though it actually bent the upper suspension supports and broke rivets on both sides - like bent enough that both supports (all of it) need to be replaced. Don't get me wrong there were a couple subtle hits on the ride where the suspension was cycling through, but the snow was deep and it was minimal - it even bent the Skins rear bumper. Anyway, that's a lot of force..... again no jumping or abuse. My buddy (the dealer) can't understand what the hell is going on to create this issue. I told him we are not fixing it until I understand what could be happening. Oh, I do carry a 3.3 gal jerry can on the tunnel. Oh, one last thing... it must be bowed out at least 3/16 to 1/4" both sides. To say I'm pissed is to say the least... THOUGHTS?

 

[mountianguy]

First thing is move this to the proclimb section, most likely you will get better feedback. Second this is not a common issue and responses may be limited, my question is where is the gas can located towards the seat or bumper? It is 20 plus pounds and at the bumper end with the leverage it could be applying enough force to cause the bending????

 

[dwight3566]

Can you post a better picture of the rear running board mounts and the rear bumper end.

 

[ippielb]

Whooped out trails, and heavy gas can on the back aren't good. Had a similar incident happen to my sled. Had 3 gallons of gas on the back, rode a whooped out trail like rank. Then got stuck and when we were lifting the rear end up, one of the tunnel gussets bust. If there is any loose rivets, that gives the aluminum room to flex, and from then on out it's a snowball effect. It will get worse and worse until it breaks.

If the back is bowed, i would look farther up as well at the front mounts. Because if the back moves the front moves as well.

Look into CR racing drop brackets for the rear. Supposedly are stronger then the Cat.

 

[Cat401]

I have a question that I hope the forum can help me figure out.... I have a 2015 M8000 limited 153 track with approx. 2200 kms - I've owned since new and am old (50yrs) and a mediocre rider. I don't jump or abuse my machine in any way. I do go to the mountains a lot. Here's the list of upgrades that have all been done by my dealer: Upgraded shocks to raptor front and rear, upgraded running boards to proclimb, 2016 front end, skis,there's more, but its not pertinent to my issue. I noticed in November (prior to first ride this season) that both sides of my tunnel at the upper supports were starting to bow out (no wrinkles) - nothing major, but I weigh approx. 240lbs and thought the issue was because the stock Fox 2 air shock was bottoming out at 140lbs pressure all the time creating a lot of stress. I then changed out the rear shock to a raptor and adjusted the spring tension to where I had full movement of the suspension, but did not bottom out. However, I was riding this past weekend with my dealer (riding buddy) and noticed near the end of a ride (was rolling the machine over to get unstuck) that the issue of "bowing out" was back. This time though it actually bent the upper suspension supports and broke rivets on both sides - like bent enough that both supports (all of it) need to be replaced. Don't get me wrong there were a couple subtle hits on the ride where the suspension was cycling through, but the snow was deep and it was minimal - it even bent the Skins rear bumper. Anyway, that's a lot of force..... again no jumping or abuse. My buddy (the dealer) can't understand what the hell is going on to create this issue. I told him we are not fixing it until I understand what could be happening. Oh, I do carry a 3.3 gal jerry can on the tunnel. Oh, one last thing... it must be bowed out at least 3/16 to 1/4" both sides. To say I'm pissed is to say the least... THOUGHTS?

more pics would give a better idea but you are carrying over 30 lbs on that tunnel....probably what caused it

 

[Vosh]

Here are some additional pics..... As you can see the some of the rivets are broken, and the supports are bent. I have a pic of the gas can on the tunnel, but can't get it to load. That's ok as it sits close to the back of the tunnel - I have the tunnel bag that comes with the limited addition right after the seat.

 

[Vosh]

Is that upper suspension bracket (on one side) consist of 2 pieces riveted together?

 

[SR Viper MTX]

I have exactly the same issue except its on a 2015 Yamaha SR Viper MTX 162. Noticed it about a month ago and have just been paying attention to the area above the LH rear skid mount. I don't carry anything on my tunnel, I weigh a hefty 180#s and I don't perform death defying jumps or anything crazy and this is like my 8th sled. Brought it in to the dealer where I bought the sled and they have not ever seen anything like it so far. They took pics and are submitting it to Yamaha for hopefully warranty repair. Lets put it this way, they better cover it, especially with 1 full year left on the overall 3 yr warranty. I brought the sled back home and was going to tackle the repair, but after just dropping the rear skid bolts and got a clear full view it looks like just one side has been effected (LH), (RH) is just fine. As I look and assess the failure, I'm gonna say that the plates that make up the rear mount have less tensile strength or less hardness. The plates are of really good thickness and where it is bent is where the plate is perfectly flat on the bottom of the tunnel side. Either the plate needs to be formed with stamped in gussets or the hardness needs to be up to spec. Its funny that yours is a 2015 also, hmmmmm! Well since finding your post and assessing the situation I have thrown the ball in Yamahas court to repair under warranty, That's it!!

 

[roadlinur113]

I have exactly the same issue except its on a 2015 Yamaha SR Viper MTX 162. Noticed it about a month ago and have just been paying attention to the area above the LH rear skid mount. I don't carry anything on my tunnel, I weigh a hefty 180#s and I don't perform death defying jumps or anything crazy and this is like my 8th sled. Brought it in to the dealer where I bought the sled and they have not ever seen anything like it so far. They took pics and are submitting it to Yamaha for hopefully warranty repair. Lets put it this way, they better cover it, especially with 1 full year left on the overall 3 yr warranty. I brought the sled back home and was going to tackle the repair, but after just dropping the rear skid bolts and got a clear full view it looks like just one side has been effected (LH), (RH) is just fine. As I look and assess the failure, I'm gonna say that the plates that make up the rear mount have less tensile strength or less hardness. The plates are of really good thickness and where it is bent is where the plate is perfectly flat on the bottom of the tunnel side. Either the plate needs to be formed with stamped in gussets or the hardness needs to be up to spec. Its funny that yours is a 2015 also, hmmmmm! Well since finding your post and assessing the situation I have thrown the ball in Yamahas court to repair under warranty, That's it!!

Gonna have to keep a close on my 16 Viper in this area too. I bought the Viper because I wanted to try the ProClimb chassis and my buddy (die hard Cat man with 4 of them) assured me the Cat was the strongest chassis. Hope you guys get it sorted out, keep us in the loop?

 

[roadlinur113]

more pics would give a better idea but you are carrying over 30 lbs on that tunnel....probably what caused it

3.3 imperial gallons weighs 24 pounds. Sorry OP but just giving precise figures. If it's a 3.3 US gallon tank weight of fuel is 20#. Admittedly this is my first Cat chassis but I hope the tunnel is strong enough to pack fuel (in the closest to seat position)