Clutch issues after rebuild

Hey everyone. I just went through a clutch rebuild where I replaced all of the plates in the clutch. Did this because I was getting some slipping in 2nd gear at higher rpm’s (maybe 6500+). But after the rebuild I am getting a lot of stuttering in the gear box in lower rpm’s in 2nd gear. I followed the clutch rebuild video closely and still having this issue. Is there anything outside of the clutch that could be the cause of this? Or is it worth popping it open again? Not sure what I would do to fix this though when I’m in there.

 

What bike do you have?

 

'83 XJ750

 

What does "stuttering in the gearbox" mean? Is this a noise,, or a vibration in the foot pedal, or ?????

 

Wondering if this vibration issue was present before the changes but never noticed because of the slip or maybe there's an imbalance going on if the dots were not connected. just an idea is all.

 

Stuttering referring to a slipping. Should have clarified that. No noticeable noise. But not a complete slip either. Feels like its trying to catch but doesn't catch completely, so I get power to the back wheel and slipping back and forth at very short intervals in lower rpm's in 2nd gear. This wasn't there in that rev range before. I had solid power until it would slip in higher rpm's in 2nd gear before the rebuild.

 

The only thing I can think of would be the damping springs on the backside of the clutch basket itself used to dampen and give some play between the engine crank and the driveline itself. Could this possibly be an issue with the engine having an uneven power delivery be it carbs out of sync or uneven compression that is being felt on the lower end? I know with my SECA 750 I can sometimes feel this below about 2000 RPM in 2nd gear crawling in traffic so maybe there's a coincidence of issues going on here with yours.

 

I haven't checked carb sync in a few months but it was tuned using carb tune and are pretty well in sync. Also changed out valve shims so all of those are in spec and helped out with compression. Not sure about the dampening springs on the back side of the clutch basket. Are you referring to the ones right behind the clutch cover that you need to take out to get to the clutch plates? If so, I replaced those as well.

 

Dampening springs.

Did you align the lever on the clutch case?

 

Thanks Franz for the images. The springs I'm pointing at are behind the clutch basket shown in the top image and their purpose is to provide some "give" to the driveline and take up the shock, if the engine isn't firing evenly on all four this will cause an oscillation from the variations as each cylinder fires at 180 degree intervals bucking against the springs giving that choppy feeling especially in the low gears at light load throttle, this gets multiplied as the primary drive ratio from the crank to the clutch gear is 1.672:1. Goose it and the firing evens out while loading the springs harder taking up the slack, sometimes you can still feel it as a slight pulsation. Have you done a compression check and know for sure all four are firing evenly on the light throttle?
Aligning the clutch lever is equally important as this sets the overall release/engagement balance, I trust you aligned the little dot on the diaphragm with the one on the drive basket itself? This is a balanced assembly and the relationship needs to be maintained... learned this one myself.

If all is right where it should be the clutch will have enough bite to hold the front off the ground in 1st with little effort and 2nd will go about halfway thru the RPM range depending on how experienced you are at this. It will also have the holding power for full throttle 9500 RPM shifts all the way to the top end without slipping provided you're using the correct wet clutch rated JASO MA2 motorcycle oil. I'm running 20W50 conventional in my 81 SECA 750 and I ride it hard.

 

Was not aware of these springs in the above picture. I can recheck the compression to make sure that it is dialed in, but I am not getting the choppy power delivery at light throttle. This only happens if I open it up entering 2nd gear. I aligned the dot on the clutch basket and plate with the retaining springs right behind the clutch cover.


(Photo showing alignment of lever on the clutch case) I also adjusted the free play at the clutch lever on the handlebars as well to make sure I am getting proper free play/actuation.

I use a JASO MA2 15W40 oil I saw recommended here in a past post.

 

Is the noise similar to this suzuki?



My 900f was making a noise like this. It was the clutch basket bearing. Unlikely your problem as its only happens in second gear.

 

Franz, no, nothing like that. I don't hear an audible change from just your standard engine noise.

 

Good its not the bearing then.

 

And not the other gears if you open the throttle at lower rpm?

 

Do you have the original Yamaha fuse box? Change it for a blade one if you do. Ignition issues can be caused by that but all the time going into second gear unlikely.

 

I ran into an issue like this.
Clutch slipped under power sometimes.
Rebuilt with new metal and fibre plates.
Better but still slipped sometimes.

Ended up being the hub and the pressure plate were from different models.

Difference after replacing with the matching pressure plate to the hub was about 5mm of depth in the basket.

Noticed the clutch is different across a few of the models. The codes are stamped on the bits.

 

I remember that l am sure @chacal mentioned it too.

 

Haven't felt it in any other gear.
Got new blade style fuses, but wasn't able to find a fuse box with a small enough form factor, so I just did 5 inline fuses/holders.
@cds1984 not sure what you mean by this, but open to exploring any avenues to fix this. Can you elaborate, please?

 

This the small thread I started.
https://xjbikes.com/forums/threads/xj900-31a-clutch-boss-image-wanted.132432/

 

Thanks @cds1984 I will crack it open again and take a look. Where can I find the stamping though? And I am looking for all parts to say 5g2?

 

They should all say 5g2 for the 750.

Stamping from memory... Internal side of the pressure plate and boss. Rear of the hub against the engine.