Drive line problems

[TopCatGr58]

Hey again,

No, you don't need to split the cases, just go in like you did for the forks. There is a pictorial guide to assist you in getting the countershaft and all of it's gears out this way. The gears you should need to grind are on the countershaft, not the primary shaft. Depending on your choice, you can leave the engine in the frame, and flip the whole bike over, or just take the engine out, but would suggest you pull the clutch basket while in the frame so you can use the rear wheel as a wedge. But you might also have an air impact wrench, then in the frame is moot point!
T.C.

[3Phase]

I'll start of by saying Hi.

Hello, John, welcome to the forum!

It feels like a shift fork is bent but only feels like it skips 1 tooth when it does it, but it does it in any and all gears.

If it skips in all gears it could be the primary shaft spring-disks are weak or broken. The primary chain is in the middle of the crankshaft and goes to the middle of the primary shaft. The primary shaft has a spring-disk clutch and forked saddle arrangement on the shaft that allows it to slip under high torque loads without breaking parts.

You can get a look at it if you drop the oil pan but you have to pull the engine and split the case to replace it. Take a look at the online parts catalog on Yamaha's website and you'll see what it is supposed to look like.


Regards,

Scott

[Rice Ya]

I did notice when I had it apart that the primary chain had alot of slack to it. I still haven't had a chance to get over and look at it again.

Thanks Scott I'll check it out if I have to pull the motor. Alot more to this shaft drive than i figured. I think I'll stick to chain drive

[3Phase]

I did notice when I had it apart that the primary chain had alot of slack to it. I still haven't had a chance to get over and look at it again.

Thanks Scott I'll check it out if I have to pull the motor. Alot more to this shaft drive than i figured. I think I'll stick to chain drive

You're welcome, Ricey!

The clutch does the same thing with a shaft or a chain drive. The primary shaft clutch is a plain, old-fashioned, energy dissipation device. If the engine, mid-drive, transmission or final drive suddenly stops moving or tries to overrun (you downshift too far or lock the rear brake at 8,000 RPM diving into a corner) the primary clutch will, hopefully, slip instead of grenading the engine and/or transmission.


Regards,

Scott

[TopCatGr58]

Hey Scott,

I thought about a slack primary chain waaaaay back in the recesses of my mind, but didn't mention it. I forgot about the Primary shaft clutch!
If it was ridden very hard, could have really stressed the Hy-Vo chain. Have heard of folks describing a knocking sound that turned out to be the Hy-Vo chain slapping against the case! The Hy-vo chain can be gotten from Partsnmore.com about $135.00 IIRC.
T.C.

[3Phase]

The Hy-vo chain can be gotten from Partsnmore.com about $135.00 IIRC.
T.C.

You're right, T.C.! It could very well be a loose Hy-Vo chain skipping a tooth under accel/decel and slapping the engine case.

I haven't seen anything about strengthening or replacing the primary clutch from the people that build these engines up to mind-boggling horsepower. I wonder if the clutch just keeps working up to silly numbers or if they had a custom primary shaft made without the clutch? Be a bit of a let down to pop the clutch at the strip or a stoplight and just hear the primary make interesting noises.


Regards,

Scott

[Rice Ya]

Got the motor out (again) tonight.
We'll get it apart and let ya know what we find out. (shaft drive)
I will be going thru the tranny gear by gear and checking out that big chain thingy.

Thanks for all the the help guys, it is much appreciated.

John

[Rice Ya]

Ok, back again guys. Got the motor tore apart and the only thing we could find wrong is the the primary chain has 3/4" slack in it but showed no signs of it slipping on either gear. My buddy found a used chain and and primary shaft clutch off fle-bay who the seller guarrentes that it's good for $65 shipped. I checked the tranny gear by gear and it's fine so let's hope this fixes it or you may see some for sale adds on here and we'll start parting it out(he wants to throw it in the trash).

Thanks again for all the suggestions.
John