Mag side engine strap bolts

[Danbot]

Had a bad vibration come up the other day, limped it out and here's what I found today:

On the mag side engine strap, the rear bolt had apparently rattled itself out... threads on the bolt, and in the engine case are clean, I found the bolt in the belly. The front bolt was still in place but the threads in the case are destroyed.

Seems to me the sequence of events were:
1- rear bolt was not tight and/or had no threadlocker on it and rattled itself out.
2- front bolts case threads couldn't take the heat and peeled.

I started out planning to use helicoil to repair the case, but I can't find anything longer than 1/2" depth which is about half of the thread contact in the stock arrangement. Now... I think going oversize might be the answer.

Thoughts? Similar problems?

 

[2Quickrides]

Go oversize, smallest size that will eliminate the damage.

 

[High Velocity]

Dan, I had the rear, pto side, bolt come out. Found it under the primary clutch and it took an hour of looking with a mirror to figure out where the bolt came from. Do you still have warranty ? If so, call your dealer.


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[mtncat1]

Had a bad vibration come up the other day, limped it out and here's what I found today:

On the mag side engine strap, the rear bolt had apparently rattled itself out... threads on the bolt, and in the engine case are clean, I found the bolt in the belly. The front bolt was still in place but the threads in the case are destroyed.

Seems to me the sequence of events were:
1- rear bolt was not tight and/or had no threadlocker on it and rattled itself out.
2- front bolts case threads couldn't take the heat and peeled.

I started out planning to use helicoil to repair the case, but I can't find anything longer than 1/2" depth which is about half of the thread contact in the stock arrangement. Now... I think going oversize might be the answer.

Thoughts? Similar problems?

I wouldn't recommend using an over sized bolt, one standard heli coil will hold torque no problem and be stronger than the original threads, If you are worried about it you can stack the helli coils into the hole to fill it completely

 

[sledhead9825]

On my 2011 turbo 800 RMK had the same problem. Drilled and replaced all 4 with bigger bolts. Never had the problem again. Be careful drilling out mag side.

 

[AkLogan]

My 11 did the same thing. We stacked 2 heli coils in each hole and worked fine.

 

[savagecanuck]

My rear bolt that goes into the casting came stripped from factory on my 14.Probably put in with an air gun.I'm having it fixed on my 300 mile service

 

[skibreeze]

I wouldn't recommend using an over sized bolt, one standard heli coil will hold torque no problem and be stronger than the original threads, If you are worried about it you can stack the helli coils into the hole to fill it completely

X2.

 

[sledhead9825]

X2.

Why wouldn't you use a oversize bolt?

 

[mtncat1]

a standard size bolt with a heli coil installed correctly is a much better repair, will not compromise , the case integrity and uses factory hardware, over sizing the bolt is just not the right way to fix a damaged case unless it's a last resort.

 

[Danbot]

Thanks for the replies
Those of you that have used two helicoils, how are you installing the second coil so the threads line up properly? The type I have access to have the tang that gets broken off after installation.

 

[LoudHandle]

Thanks for the replies
Those of you that have used two helicoils, how are you installing the second coil so the threads line up properly? The type I have access to have the tang that gets broken off after installation.

When stacking Heli-coils you run the second one in until it almost touches the first one. When you break off the tang it leaves a small gap but nothing to worry about. I also use permanent Loctite on the outside of the Heli-coils when installing them. FWIW

 

[sledhead9825]

a standard size bolt with a heli coil installed correctly is a much better repair, will not compromise , the case integrity and uses factory hardware, over sizing the bolt is just not the right way to fix a damaged case unless it's a last resort.

Why would going up 1 size compromise the integrity of the engine case?

 

[2Quickrides]

K, so to install a helicoil (a winding that grips the case and bolt) you drill and tap the hole oversize......
To install a larger bolt you drill and tap the hole oversize......
If a bolt with a helicoil was the best way to bolt things, manufacturers would be engineering stuff that way new that requires extra strength, do they? No. They use a larger stronger bolt that has more tensile strength and thread surface so it's less likely to tear out.
In fact depending how stripped the case is there's a good chance he can use a bolt with a smaller outside diameter than the helicoil which would leave more material there.

Helicoils are used because they are a quick easy fix using the same hardware, end of story.

Please, explain to me how a helicoil is a better fix in this case?

 

[Danbot]

Well, last night I attempted stacking 2 helicoils in a old 900rmk case set I had in the basement... I am not at all liking how they line up, and how there is a gap..... after 4 attempts I got them to line up so there was no thread bind, but I do not want to try this on my pro engine. It just feels wrong.

I will be drilling and tapping for an oversize bolt. I second guessed it after the comments here, and did some research.... I can see nothing wrong with going oversize, in fact it will be at least a little stronger than the stock arrangement.

 

[cateye5312]

Dan, I had the rear, pto side, bolt come out. Found it under the primary clutch and it took an hour of looking with a mirror to figure out where the bolt came from. Do you still have warranty ? If so, call your dealer.


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Me too - On New Year's day I pulled the side panel off my wife's 2012 600 (read that again - yes it was a 600 - the supposedly bulletproof ones LOL) and laying under the primary clutch was an engine strap bolt. My dealer pulled the motor and ended up helicoiling that bolt plus one on the other side as well.

You gotta wiggle like crazy to get a mirror in there to look at the bolts. Evidently though it is really easy to pull these motors out. Dealer had it out and back in in about an hour.

Oh, best part, dealer comped the repair because I bring them a lot of work! Bonus!

 

[sledhead9825]

K, so to install a helicoil (a winding that grips the case and bolt) you drill and tap the hole oversize......
To install a larger bolt you drill and tap the hole oversize......
If a bolt with a helicoil was the best way to bolt things, manufacturers would be engineering stuff that way new that requires extra strength, do they? No. They use a larger stronger bolt that has more tensile strength and thread surface so it's less likely to tear out.
In fact depending how stripped the case is there's a good chance he can use a bolt with a smaller outside diameter than the helicoil which would leave more material there.

Helicoils are used because they are a quick easy fix using the same hardware, end of story.

Please, explain to me how a helicoil is a better fix in this case?

Thank you. I really don't understand, where some of these guys get there info.
Another thing Dan, have a good look at the strap. Make sure the mating surface is still square and that the mounting holes are not out of round.
If you do want to stay with OEM size bolt you could use a Time Sert to repair the threads.
IMO the OEM bolt is a little on the small side. Like I said in a earlier post went up a bolt size and had no more problems.

 

[Danbot]

Again, thanks for the replies. You all helped me make my decision.

The repair is complete, and I went for a 10 minute rip to seat the clutch and make sure everything was alright. She's back to her proud self again! My strap was still mint, clean & flat.

I do have warrantee left, but the wait for dealer time would have cancelled a trip this weekend... unacceptable. I know the job is done right, and I have gained intimate knowledge about my sled in doing the work. I spent a total of $23 on this repair, would have been less but I needed an odd size drill bit that I did not have.

 

[2Quickrides]

Good to hear it's good to go again!

 

[sledhead9825]

Good to here the straps are okay. They get messed up quick with a bolt missing ,and are spendy.