**Official Clutch Rattle Removal Thread w/ Pics**

[yamaha1973]

Lying in bed last night I started thinking; What is the reason for the crank having the stubshaft? Does it serve a purpose being constructed like that? Or ?

Its for clutch RPM reduction, the motor will spin faster than the clutches, belts dont hold together to well after 9,000 rpm

 

[Beenba]

I would think that having play in the splines would create a lot of inertia at those RPMs and it would be stressing the splines and shafts more than necessary- plus you don't see it on other motors so why here? I don't know much about street bikes but does the same condition exist in the bikes that use these motors but with a flywheel instead of a clutch?

I agree, the rattling would cause additional stress on the splines since it is now acting like a hammer with some of the inertia rocking back/forth. But it is really only at idle and the stress is likely very minimal. It doesn't take much to cause an annoying sound. My spines looked new and I have 7400km so really this fix is only to remove the sound. No real reliability gains by doing this.

The way I see it, Yamaha used the stub shaft as a cheaper/easier design alternative. If they made the crank longer to extend out to the clutch, they would then have to add additional wet main bearings out closer to the clutch (and more oil pressure/flow associated with it) and holding the cranks tolerance might be harder. Maybe the engine was just too short and they needed to add the length to the crank to keep the mass centered in the sled? Maybe its splined in case the motor made peak HP at 12,000 like the apex and needed reduction (ok thats a long shot lol)...but you never know!

Lying in bed last night I started thinking; What is the reason for the crank having the stubshaft? Does it serve a purpose being constructed like that? Or ?

Its for clutch RPM reduction, the motor will spin faster than the clutches, belts dont hold together to well after 9,000 rpm

On the apex yes, but on the Nytro the stub shaft is 1:1 on the crank.

 

[kimoajaj]

Good points there Beenba!
Its actually what I also thought but its sometimes hard to find the right words when you are writing in a foreign language (good excuse, huh??)

Yamaha1973, on the Apex yes but not on the Nytro (as beenba also said). Dude last year I had a 1973 Yamaha XS650 with a lot of mods, I miss it!! )

Today I got my new oillite bushings, will be installing them in the weekend, maybe I will have to try the rattle fix also!

 

[ViperTurboPete]

What concert did you see?

 

[yamaha1973]

Good points there Beenba!
Its actually what I also thought but its sometimes hard to find the right words when you are writing in a foreign language (good excuse, huh??)

Yamaha1973, on the Apex yes but not on the Nytro (as beenba also said). Dude last year I had a 1973 Yamaha XS650 with a lot of mods, I miss it!! )

Today I got my new oillite bushings, will be installing them in the weekend, maybe I will have to try the rattle fix also!

My bad, I shouldnt have assumed that

Sweet bike! Although my user name has a slightly different meaning

 

[kojack]

Just started the sled. It made a huge difference. not the only little rattle is probably coming from the weights bolt. But the big annoying clunking is gone. Soo Happy!!!!!

 

[fxnytroxtx]

Just started the sled. It made a huge difference. not the only little rattle is probably coming from the weights bolt. But the big annoying clunking is gone. Soo Happy!!!!!

glad to hear it worked out! Just put mine back together but I used wurth and that sh#$t is strong! I have zbroz with upbushmans bushings and it had play I applied some in there and it's rock solid, now just need to see how it's gonna compare to locktite 660 I used there without good results.

 

[fxnytroxtx]

What are the torque specs for all the bolts on this job including primary? Thanks

 

[Beenba]

Guys hold up. 640 did not work for me. Fired it up and the rattle was still there. I just tore the stub shaft out again and it hasn't fully cured. I may have had a bad bottle of 640, I'm not sure how long it was on the shelf at work. You could see it was starting to cure but was not fully sealed.

For anyone who has used the 640 already, give your sled a full week just incase. I do believe I used a bad bottle of 640 but you never know. Better safe than sorry.

Kojack what number did you use. Can you grab the clutch and rock it back and forth and see if the back sheve moves at all (without turning the motor over)?

I am cleaning up my parts right now, it's coming off just like the minute I put it on. Weird.

Edit: I'm 99% sure I had a bad bottle. I just did a quick bench test with the bottle of 640 and my bottle of 680. 0.020" gap between the parts I'm testing. The 680 is already set and the 640 is doing nothing.

 

[1975FA]

I was told once that for loctite to set up, it required the absence of air like in two tightly squeezed togeather compnents. Has anyone thought of devcon epoxy steel? I have used it on loose splined steering arms on farm tractors with good success.

 

[kojack]

My local part supplies didn't have loctite so I bought it's equivalent. I bought the Permatex brand and it's the red one but not liquid, It's gel and smells like cherry. Looks like a candy push thingy. Almost want to lick it and taste it but the wife said it was a bad idea. So the spline had it but not me Not sure if its totally cure cause' i didn't open to check but when i started the sled almost all the rattling is gone. The only rattling i hear now is from the primary itself. But with the side cover back on, I barely ear any clunking.

Boomba, I'm not sure if one of the loctite # u guys used but If i read correctly some need heat to cure. I havent did deep in the loctite specs as I was using a different brand. I'll go check the clutch right now to see if she moves. be back in a sec.

fxnytroxtx, the primary clutch torque setting is 120 Nm (12.0 m • kg, 85 ft • lb) 60 Nm (6.0 m • kg, 43 ft • lb) if you dont remove the primary from the shaft. For the 4 little bolts that hold the bracket and the 2 other underneath i'm not sure on the torque specs. Couldnt find them at the time but they weren't tight so I just tightened them until snug and a little more just because I can.

Update: I've check the clutch again. There is still a slight play in the clutch but the rattling is way less than before. Not sure if the gel is dampening some of the rattle but it will have more than enough time to cure as the snow is still too far to ride. I do not have any heat in my garage also so i'm sure it's making a difference on curing time. I am already pleased with the result and my sled only has 2500km on her. It has about another month to month 1/2 to cure before i ride it.

 

[Beenba]

Killswitch Engage was in Toronto. Its a metal band, and they were playing a 10th anniversary tour with an album I used to rock out to in high school when I was a drummer. Great show, my ears are still ringing

What concert did you see?

You guys are right, loctite does cure in the absence of oxygen/air. The splines in the stub shaft should be a near perfect scenario for this.

kojack you should be fine, the gel stuff may take longer to cure but it should fill the voids well and dampen the sound.

My 640 must be bad, may have got frozen or something. It had a full 72+ hours to cure in my heated shop and it was still runny - not right - i have used this stuff before filling larger gaps and its set up within 30-45 minutes.

I re-did it with my 680 bottle I know is good. Little less strength but cures a bit quicker. My bench test of 680 is already rock hard (sat for about 30 mins) and I threw it around the shop and pulled on it and couldn't break the bolt free form the steel tube. Now lets compare that to my bench test of 640....its still runny and doing nothing, just like it was on my splines

Sorry if I'm ranting I just want to make sure everyone knows everything!

 

[ViperTurboPete]

Cool! I was a drummer in a metal band also. You can't kill the metal!

Too bad the mod didn't work. I felt the disappointment over the net. I really hope you are satisfied with the next test. Sounds very promising with Kojaks breakthru.

 

[Beenba]

Ok ok I think I'm getting paranoid Just drove to the shop and gave the stub shaft a good hard wiggle. No play at all anymore. The 680 is working well so far.

I am going to let it cure for 24hr (assuming the spline gaps are between 0.005 and 0.010 - which has to be worse case) it should be at 75%+ strength or more at that point. Then i'm going to try round2.

I will let everyone know how it goes, as always...the bad bottle is already in the garbage.

 

[kojack]

good job, if you know that bottle is no good, throw it out, you dont want to be doing a full job with it like the front end and realized you have to pull everything back out cause the bolt arent holding up I'm sure round 2 will work.