'10 M8 reverse grinding noise?

AkHockey10 · Sep 4, 2011

Whoa....haven't been on here in a while! Anyway...

Have a grinding noise only in reverse when getting on throttle. Took DD a part and that's not it. Next thought would be something wrong with primary? Secondary had been checked out back in Feb but may as well look at it also. Anyone have an idea??
:face-icon-small-dis
Also, sled also slams HARD into gear going forward and in reverse. Sitting at idle I slowly give it throttle and it revs up and nothing happens then bam it goes into gear. It will jolt forward and backward and will throw you off the sled if not read for it. Crazy!

ACMtnCat · Sep 4, 2011

your grinding noise is likely the drive shaft bearing it the brake caliper. Take the caliper off, youll have to get both bearings out to check them. The inside one is held in by a C clip. Tap the first one out then youll see the C clip that needs to be removed.

The harsh engagement is likely two things. The belt to sheave gap is one. The other is a combination of weights being too tight and not swinging free enough and the spindle bushings hanging up or worn out. A good primary clutch cleaning and making sure the weights are just right and swing easy will help a lot! But you may need to adjust belt to sheave gap to cure the slam your feeling.

diggerdown · Sep 4, 2011

Primary could be the cause of both problems. Depends on what you consider a grinding noise. You can also get vibes in reverse from the end of the hyfax.

bushy · Sep 4, 2011

Was told the secondary converted back to torsion spring setups can cause a grinding like noise/feel in reverse. Causes the belt to slip and hop in reverse?? My sheaves are full of belt marks. The 09 M8 I just bought is doing it. Really has a hard time getting moving in reverse. Anybody confirm or refute this? Mine is the OVS secondary kit.

ACMtnCat · Sep 4, 2011

bushy said:
Was told the secondary converted back to torsion spring setups can cause a grinding like noise/feel in reverse. Causes the belt to slip and hop in reverse?? My sheaves are full of belt marks. The 09 M8 I just bought is doing it. Really has a hard time getting moving in reverse. Anybody confirm or refute this? Mine is the OVS secondary kit.

Just open your hood and watch what the belt does when you're in reverse and start to move. Whats happening?

bushy · Sep 4, 2011

That would be too easy..I'm more of a "pull the crank out and have it straightened only to find it was a loose helix all along" kind of mechanic. lol I actually did that last year...

First sled with reverse and I'm guessing it will work better reversing on snow, but the trailer has plastic ski guides so it should have that much trouble backing out? I'll let you know what I find out next time I pull it out of the trailer.

kidrman · Sep 5, 2011

Seems like tons of threads on here about torsional kits not working well with reverse. Do you have a bud you could swap secondarys with that is still running compression setup?

RickM · Sep 5, 2011

AkHockey10

After reading your post, it sounds like you may have the torsional conversion spring setup in the driven clutch. As mentioned above, a lot of people including my self had issues with them working in reverse properly. If belt deflection is off then the helix can grind and sheaves open up and that caused the sudden jerk or grab when the belt slams in taking up the slack in the belt.
Once the sheaves are open then when you try and engage the clutch forward you have the lurch forward again. Look at your helix where the rollers ride on it in the reverse side area of roller contact. I bet you see the problem.
Hope this may help you out.RickM

AkHockey10 · Sep 12, 2011

Nice. Thanks guys!!

I FINALLY had the chance to look into the sled. Diamond drive is in healthy condition. Took off the primary and didn't see anything out of the ordinary

Its gotta be something! Giving it a good wash down (same with DD) and putting it back on. My next thing is maybe I should change my spring... It will help with the rough engagement making it smooth...in theory. Will look into the other possibilities.

WyoBoy1000 · Sep 12, 2011

What clutching and other mods do you have on the sled. When the belt is off you can grab the secondary and rotate it back and forth, this movement is from the drivers on the track, so when in reverse it turns in the opposite direction and has to turn a bit before it makes contact to the other side of the track window, if the clutch engages hard it will slam into the other side and feel harsh. Is the grinding only when the sled is actually moving or does it do it when not moving also.

AkHockey10 · Sep 13, 2011

clucthing is all stock (from the dealer). Only when on throttle in reverse does the grinding occur

AkHockey10 · Sep 13, 2011

Would it be possible that the grinding noise is just loose belt and/or clutching be out of allignment? - Could be but just running ideas through my head..

mr p-j · Sep 13, 2011

take your side panel of and keep an eye on the clutch and belt when you engage in reverse.
whit all stock clutching it is a little bit of a long shot. but harsh engagement can cause the rollers in the secondary to miss the groves in the helix and pulling down the belt in the sec making the belt grind.

something might bind in the clutch making the engagement harder then normal.

edit: do you have black markings on your sec sleeves after you had the grinding noise?

Wrenchmaster · Mar 12, 2018

I know I'm resurrecting an old thread here. My M8 does this, has anyone found a fix for this torsional spring grinding problem?

summ8rmk · Mar 16, 2018

I removed the RKT and gave it away(wasn't going to charge someone), stock 36° helix/ orange spring, never looked back. Performed very well, reverse worked 100% of the time.

Wrenchmaster · Mar 16, 2018

I'll have to try that, hear the 36 Helix works well on turbo sleds too

Tmann · Apr 1, 2018

This may not be what your looking for, but its my personal experience.

2011 M8 all stock accept for a straight helix. Ran and engaged smooth from day one running stock Cat belt 046.

I did the SLP stage 2 kit with cutler weights in the primary and left the secondary the same as prior. The engagement just about threw ya off the sled and slipped/chattered in reverse. Also was blowing belts into 100's of pieces every 100 miles.

Swapped out the belt to the carlisle extreme belt and all problems solved.

Engagement is butter smooth both forward and back, no belt blowing in the last 500 miles. The best thing is I didn't have to take anything apart to try it.

I ran the carlisle belts on my 800 big bore and my KK 900 and loved them. The stock belt was working fine until the SLP stage 2 was added then all hell broke loose.

Good Luck. Its an easy test and the worst that happens is you end up with a spare belt. The rubber compound is different so the clutches grab and engage different

Second idea is get the primary clutch bolt that has an adjustment collar which allows your to slightly compress the primary so the engagement is smoother. Think they are sold by thunder products (abc 238) kit.. Sorry I don't have the exact name for the primary bolt but I have ridden a sled with them and the clutch engagement was really smooth.

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'10 M8 reverse grinding noise?

AkHockey10

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ACMtnCat

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diggerdown

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bushy

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ACMtnCat

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bushy

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AkHockey10

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