Let's revisit the broken bolt in the chaincase

[Mountaintech]

As for holding the drive shaft in place that bolt has nothing to do with it. On the drive shaft on the chain case side there is a permanant bearing guide fixed to the shaft that turns with the shaft. This fit into the bearing housing that is fixed to the chain case side bulkhead piece with three bolts. The shaft cannot move laterally towards the chain case unless that housing were to fail and the bolts gave out.

That bolt has everything to do with holding the driveshaft in place.It performs the same function as the driveshaft nut on the non reverse chaincase, which is to draw the driveshaft to the right until the seal collar butts against the chain case bearing. You are right that the collar prevents the driveshaft from moving laterally into the chain case, but it is the bolt that prevents the driveshaft from pulling OUT of the chain case. With no bolt in place (or a broken bolt) the driveshaft is able to move laterally towards the clutch side. The only thing that limits this movement when everything is assembled is the setscrews on the clutch side bearing. If those screws come loose the shaft is able to wander from right to left about 3/16 of an inch. That is approximately the distance from where the screws usually bite into the shaft to where the shaft transitions from round to hex.

 

[Motleyone]

With no bolt in place (or a broken bolt) the driveshaft is able to move laterally towards the clutch side.


That is just not the case. If the drive shaft were to move laterally it would do so with a broken bolt and it does not. As I said before and others have said we have run a year or two with a broken bolt and had ZERO issues. In fact I forgot to tighten the set screws on the clutch side AND my bolt was broken and there was no movement of the shaft. What does stop the shaft from moving laterally to the clutch side are the 4 bolts that hold the outer bearing collar to the clutch side bulkhead. The bolt may AID in keeping the driveshaft in place but it is not the main system in place to do so.:beer;

 

[Tuesday]

With no bolt in place (or a broken bolt) the driveshaft is able to move laterally towards the clutch side.


That is just not the case. If the drive shaft were to move laterally it would do so with a broken bolt and it does not. As I said before and others have said we have run a year or two with a broken bolt and had ZERO issues. In fact I forgot to tighten the set screws on the clutch side AND my bolt was broken and there was no movement of the shaft. What does stop the shaft from moving laterally to the clutch side are the 4 bolts that hold the outer bearing collar to the clutch side bulkhead. The bolt may AID in keeping the driveshaft in place but it is not the main system in place to do so.:beer;

I agree I have also run 2 full seasons with out a bolt. I have not seen any movement on the drive shaft. On the clutch side the plate that holds the bearing (3 bolts) also keep the the drive shaft from moving.

Regardless I would like a fix and I have put the chain case on multiple times with the bolt missing. It is not impossible just annoying to be fighting that spring.

GL

 

[05REVSTER]

Pulled the chain case apart on my 09 Nytro short track with reverse and you guessed it.....broken bolt.:face-icon-small-fro

 

[sj]

pictures would be helpful

 

[stain]

Doesn't that bolt set your chain alignment? I always tighten that side of the shaft first when installing a track

 

[Ak nitro]

I took some pictures of my shaft and the visible gap that is left on the shaft and in the coller. I am replacing my track and noticed that the clutch side has been rubbing the tunnel, even though when I installed it, the track was perfectly centered, after the bolt breaks my driveshaft drifts to the clutch side, the set screws on my clutch side where even still tight. This is the second track this has happend to, I replace the clutch side bearing every year, so I know the set screws stay tight, I even loctite them. I am in the process of putting on a new 162x16x3 track, so I don't want to wreck another expensive track. The tolerence on each side of a 16 inch wide track is very small even in a CR tunnel, so the smallest bit of play on either side will cause the track to rub inside the tunnel. I put my chaincase together without setting the set screw on the clutch side bearing and with out the chaincase side bolt and I could slide the driveshaft back and forth, while this may not have given other people problems it has ruined two 162x16x2.5 tracks of mine, always wrecking the clutch side of the track. So I am going to do what was talked about earlier and make a spacer to fill the gap, it is a large gap, no wonder the bolt has been breaking, another issue is when you tighten the end of the driveshaft and there is a large gap like that, you are pulling against the spacer and chaincase bearing ,because you are pulling the whole shaft toward the bolt, it would be putting to much sideways stress on that bearing and possible causing premature bearing failure.

Here you can see where the coller has been riding, the rust colored area, the clean area is where the large empty space is between the shaft and coller.

this is how far it sits on to the shaft when everything is all assembled, there is a lot of play when it sits like this.

This is where is how far down it should be for everything to be flush.

This is my track that was rubbing on the clutch side only, it started off centered.

Here is my clutch side of the shaft, you can see where the bearing set screws have been

Down on the right you can see the spacer I am going to machine to fit the gap between the driveshaft and the coller.

 

[Mountaintech]

You're right on the money. It's what I've been saying all along. I've found that a spacer 4.9-5.0mm long does the trick.

 

[Canoehead]

Recomendation

Ok guys thanks for the helpful tips. I feel it's alittle disheartening to learn that my brand new (old stock) 09 XTX has this flaw. What do you guys think? Go in now and install spacer or wait for my first break-in ckeck up? I've pulled chain case covers before but not on this model, is it a much to do or just an hours worth of pissin around? Appreciate any input

 

[Mountaintech]

Get in there and fix it before the bolt breaks.

 

[Ak nitro]

Putting the cover back on is the only PITA if you have reverse, if you are running a 15 wide track you may never notice any of this, it wont hurt anything to wait until you have to go in there to add the spacer, except having to drill out and remove the broken bolt out of the shaft. I am really tired of dealing with this, it will be the fourth year I am running this sled and I just want to get everything right. I just cannot believe Yamaha can make such amazing motors, and then throw something together this half a@#ed!

 

[Mountaintech]

Putting the cover back on is the only PITA if you have reverse, if you are running a 15 wide track you may never notice any of this, it wont hurt anything to wait until you have to go in there to add the spacer, except having to drill out and remove the broken bolt out of the shaft. I am really tired of dealing with this, it will be the fourth year I am running this sled and I just want to get everything right. I just cannot believe Yamaha can make such amazing motors, and then throw something together this half a@#ed!

Cover is not bad to put on if the bolt is retaining everything. If you are trying to put the cover on without the bolt then I agree that it is a pain.

 

[Canoehead]

Specs

Alright I'll take it off before I even get a chance to ride the damn thing. Anybody got the specs so I can tear down and re-install same day?
Thanks

 

[Canoehead]

Specs

Do you guys think washers would work if I can get the right thickness?

 

[Mountaintech]

Do you guys think washers would work if I can get the right thickness?

Yup, I used 3 to get the 4.9-5.0mm. From Ace hardware. 2 hardened and 1 standard. 19.9mm OD, 4.9-5.0mm long, with a hole in the middle to allow for the 10mm bolt.

 

[Ak nitro]

I ended up using three washers also, I just drilled the middle out to fit the 10mm bolt.

 

[Canoehead]

Doin it

I pulled it this aft and measured a 4.9 mm gap. I'm on my way to a millright in the am to have a bushing turned (1 also for a friend while I'm at it). I'm also going to replace the bolt with an 8 vs 10 or harder bolt so the only time I hope I have to look at it again is for an oil or gear change.
Thanks again guys for your input and I'm definately going to notify Yamaha Canada on this little hiccup that they won't address.

 

[Canoehead]

Idea

When looking at this again, could one not loosen the lock collar on the clutch side and just more or less torque the driveshaft fully into the chaincase collar, or is there not enough clearance?

 

[Mountaintech]

Nope.

 

[Linc]

I thought this issue had been solved along time ago, I've been spacing the bolt for three years now, never had another problem.