Drive line problems

[Rice Ya]

I'll start of by saying Hi. I ride a 2001 Hayabusa big bore with NOS and professonally drag raced bikes for 11 years ProGas and SuperComp. I am a long time member at Suzukihayabusa.org

The reason I registered here is for a buddy that has an 80 XS1100 with drive line problems we can't figure out. Under a load an any gear it has a skip. We replaced the shift forks(they were bent) and inspected the dogs and transmission gears, and all look great.
My problem is I know nothing about shaft drives. We tore apart the whole drive assembly and can find nothing wrong and this is where the sound from the skip is comming from as far as I can tell.
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. The U joint is good, and main and final drive all look fine(to me). We have a clymers manual but it's not as detailed as a service manual would be. But i'm at a loss for what could be wrong. I have been building and riding bikes for over 30 years, mostly Suzuki's and Kaw's and all chain drive so this Shaft drive has me at a loss.

Any suggestions would be appreciated on what to look for.

Thanks
John

[Ken Talbot]

Have a look for threads about splines. There's a grease fitting on the left side swingarm that looks like it should lube something inside. Truth is, it does not get grease to where it is needed, the splines where the driveshaft connects to the final drive. The only way to lube this point ios to hand pack it when you have the rear wheel off, say for changing out the rear tire. Without grease, and you can start to get a bit of slipping.

[Rice Ya]

There was plenty of grease in there. We cleaned it all out but haven't put anything back together yet.

Thanks for the feedback.

[DiverRay]

I've NOT heard of it happening, but you may have a bad final drive. IF it was pulled apart and not properly rebuilt, it could cause problems. Good used units can be had on ebay, as some users here go for the 750/850 final drives to gear the bike for a higher top end, and better gas economy.
Other than that, it's back to the drive shaft. Look VERY CLOSE at the last 15mm of spline on the shaft, and see if you can see rounded splines, or if there is NOT an even spline/valley.

[Rice Ya]

Splines on the final drive unit all look like new and show no signs of wear or anything that would show where it is slipping, that's what's so confusing. I would think(from experiance) that if it was in the transmission that it wouldn't skip in all gears either( I have had tranmissions back cut for racing).
When he originally told me about the problem he said it only did it in 2nd, so that's why I figured it was shift forks. The 2(outside) were bent and had wear marks at the center of the Y from rubbing the teeth of the gears but showed no signs of any damage to the dogs.

I didn't know if this was a common problem with shaft drives or with this model bike.
Is there any specs on the spring in the final drive unit? It's not broken but is a little worn on the ends.

[DGXSER]

I certainly do not have your years of experience, but read along with MANY similar issues here on the forum and have completed the dremel repair on my bike.

What your suggesting about the forks sounds like someone holding the bike in gear when the dogs were skipping out. As you may have read on here, or seen yourself, is it a VERY common problem with the trans design that the ends of the dogs round off a bit and begin skipping in and out of gear. It is very common to strike first and second gears, but many have had issues with other gears as well. Sounds like perhaps the bike your in has been raced or "well used", and may have all of them worn but good. From experience I can tell you that it does not take much of a rounding off for it to skip out when hitting the gears hard. JMHO.

[Rice Ya]

Well I talked to the owner at the local Honda Yamaha dealer and he is at a loss too. I'm going over tonight to check the swing arm spline and cup as this is the oly thing we haven't looked at so maybe I'll get lucky and find the problem there. The dealer said he wouldn't even touch it because of the age and the availibility of parts and to clean it up and put it on display in the livingroom rather than thro anymore money into that old of a bike. I know alot of you like these old school bikes but there comes a time when you have to draw a line at where to stop beating a dead horse.

Thanks very much for all your input and if we get it figured out I'll let you know.

BTW here is what I ride. 2001 Busa, 1397 big bore, with NOS wet kit
265 rwhp.

[DGXSER]

The dealer said he wouldn't even touch it because of the age and the availibility of parts and to clean it up and put it on display in the livingroom rather than thro anymore money into that old of a bike.

It is funny how often the folks who sell new bikes will say that. . And yeah it does rack up the bill when your paying the professionals to do the work. No offense to you or your profession. I do not come cheap as an engineer either!

I know alot of you like these old school bikes but there comes a time when you have to draw a line at where to stop beating a dead horse.

Well, if you feel it is time to put it out to pasture, you can just give it to me and I'll see it gets a "proper burial"!!

BTW here is what I ride. 2001 Busa, 1397 big bore, with NOS wet kit
265 rwhp.

I know that thing will run circles around an XS11, but still, just how much is tied up in that beast? compared to how much is in that 11??

[Rice Ya]

I know that thing will run circles around an XS11, but still, just how much is tied up in that beast? compared to how much is in that 11??

Just a couple bucks more.
You can't put a price on a good time.

[cywelchjr]

Just a couple bucks more.
You can't put a price on a good time.

I don't know. While I busa would be a fine machine to own and ride, the classics have their own draw. In addition, I am not comfortable with sportbike seating style. I prefer the upright seating style of the 11 and I'm while I'm not uncomfortable with the seating on a cruiser, I'm not really happy with the handling on them.

[Ken Talbot]

BTW here is what I ride. 2001 Busa, 1397 big bore, with NOS wet kit
265 rwhp.

Sweet!

[petejw]

Just something else to check,
the shift pawl is adjustable, not only do the dots need to line up,
in 2nd gear theres a line on the shift drum that has to align with the line of the shift lever.
if you have the clymers, check out pages 125, 126
if the adjustment is out it could do the things you are describing.
hope this helps you out.
btw beautiful bike.

[TopCatGr58]

Hey Pete,

That adjustment on the shift drum is merely to get the shift pawl into the proper position to grab the shift drum pins to be able to make the shift drum rotate properly with one shift lever action, however the shift drum has a star pattern on the end that meshes with a spring/ball and so once it is shifted the drum "should" rotate to the proper shifted position due to the ball/spring pressing on the star until it fits into the groove of the star.

Rice Ya,
I think DG really hit the right idea, that IF it's skipping in ALL gears, that it probably got ridden very hard, and the bent forks are evident of that, and of the PO trying to hold the gear into position to keep it from skipping. I've heard of the skip so far occuring on gears 1-3, but with enough rough handling, and as the lower gears wore, more stress would have been put on the higher gears. The dogs and slots on the XS11 ARE SQUARE CUT, no dove tail type angles at all, and as was stated it takes very little rounding off of the gears dogs to cause them to start slipping apart under load!

I don't know if you split the cases to replace the forks, or if you followed the 1st/2nd gear Dremmel guide technique of going in thru the tranny pan, which is possible, then you should be able to pull the countershaft and all of the gears and using a die grinder, put a small undercut on ALL of the dogs/slots for all the gears, vs. putting some $250+ into buying all new gears, and put it back together and he'll have a great ride.

T.C.

[DGXSER]

Just a couple bucks more.
You can't put a price on a good time.

Now substitute an XS11 into that thought, My point exactly!!

[Rice Ya]

Pete, I checked all the alignments on the shift paws and they were fine, thanks.

T.C.
The motor was out of the frame and I did go thru the oil pan to do the forks. My buddy didn't get off work in time to do anything today but if we can't find anything with the spline and cup in the swing arm I guess the only thing to will be to split the cases and take the tranny apart gear by gear. I was hoping I wouldn't have to do that but it may be the only way.

Thanks for all the help.