8000k's chain XS

[pggg]

Checking the drive unit spline it seems worn a lot. Hopefully what it is is the L/H bearing which I remember stuffing up by hitting the race with a hammer the wrong way back to front. The bearing was rattly but skimping on another $25 might cost a whole spline. I removed the drive unit and checked everything inside.

DEFINITELY MORE WEAR on the spline teeth. Will put in a new bearing properly this time, then see what happens. Sprockets are still brand new condition but have destroyed an el-cheapo chain already. This thing is hauling ass at the ton in 4th - hit the gas at 5500 revs and it's hitting 200KPH in a blink.

[pggg]

Here's a pic of some middle drives stripped down. The worn spline on the left is tapered now but was O.K. 10,000 k's back. Common sense says it's the L/H bearing not aligned perfectly true. Those chaindrive converted XS11's with no L/H bearing would crap out before long I'd say. Last pic shows where to grind off 4mm thick of alloy to fit a 14 tooth sprocket.




Also doing a swap from 520 to 530 chain as a TL1000 rear sprocket fits the ZXR wheel. XS has grunt to deal to chains man. 520 is fine, but 530 should last longer with all that torque.

[pggg]

Here's a plan of an improved design on this chain unit. Due to that uneven wear on the spline teeth, I'm picking there's some small flexing on those bracing rods, as when power - on, the spline is always under rearwards force. The whole thing feels rock solid as is, but a steel plate welded to the frame, and another steel plate bolted in place as in the pic, would brace that bearing unit stronger and better.



5 minutes on a welder and an hour hacksawing some steel plate and a few extra nuts should do it.

[mro]

Just guessing from pic, plate w/two bolts (top) only about one inch high???

might want to extend welded bracket up about 1/3 to just below side cover and plate w/two bolts would then have a built in gusset.

Are you using grade 8 bolts. Little/No "give" in a grade 8.

Don't know if what I mean is what your reading


mro

[pggg]

Hey mro, not quite sure how you mean by a built in gusset? Always pleased to hear any suggestions. The front 6mm bolt is high tensile, but not the three 8mm threaded rods. 1 metre of high tensile 8mm is $40. 1 metre of 'normal' 8mm is $6. So of course scrooge is using the $6 stuff No discernable flex though. Will splash out on high tensile bolts all round, and some extra bracing.

[LoserShoes]

Umm, what about the fact the engine is rubber mounted? Might just rip a big chunk out of the frame where it is welded? Or bust up the case?

Steve

[mro]

PITA Problem

What Steve says could be a prob..
Vibration could fatigue metal either at your new brace or transfer some where else and cause a "catastrophic" failure. Could take awhile to happen or maybe not. engine vibration would be transferred to gear shaft too.

Can you make a housing or partial housing which the bolts holding the outer gear can tighten up on to middle drive??

That should help to eliminate any "torque"/movement of the outer bearing.


Too bad your not in the neighborhood. Would love to help/tinker with your project.


mro

btw

have you read the whellee post.
Bet your rig can pop at will.

[TopCatGr58]

Twist and Shout!

Hey PGGG,

I have to agree with Steve/Losershoes, you're considering mounting a permanent fixture to the frame and linking it with a moveable part....the engine on rubber mounts!?

I would think some other plate pieces positioned between the outer bearing baring plate and the base case, to stiffen up the connection instead of relying on the threaded rods alone? What about some some steel square or round tubing fitted over the threaded rods between the case and the outer plate!? I think you can have several options of bracing, but NOT to the FRAME!
T.C.

[pggg]

The PITA is the chain setup runs smooth and performs great, so wear on the spline end is a bit strange. Riding along and putting a gloved hand on the drive unit, it's smooth as. The camcovers always seem to vibrate, but not much vibes down lower. I was thinking hopefully tacking a plate between unit and frame shouldn't be too much of an issue for vibration. Bad guess? That Aussie raceguy removed the rubber engine mounts and stiffened up the whole bike. But putting in H.T. bolts is a start. It's quite possibly nothing to do with flexing - tap the unit with a hammer, it feels stiff and solid. Did I mention a bearing was a bit loose at the start? I still prefer a road cruiser on the XS. 2 hour job to throw all the shaft parts back on. Still have a brand new Conti Tour 130/90/17 on the XS back end. Seems a waste

[mro]

"out of alinement?"

Bad bearing?

How did you measure distance between L/H bearing plate and where you have it bolted to? caliper?

Also torque when cruising and when cranking a little different. 60 plus pounds might be enough to "twist" it when wot, (out of alinement), then let off and it would go back?

Hard to diagnose such a thing from thousands of miles away

hope it was just the bearing.



mro

[pggg]

Yeah mro, bearing unit is floating then everything is slowly locked tight with nuts. Front plate may have had some uneven pressure on it. Will be extra careful when tightening it back up again.

[LoserShoes]

I think you really need to replace the inner nuts with sleeves, like a piece of pipe the correct inner diameter. That way the studs could be put in tension and be less likely to twist and distort.

Steve

[pggg]

Shoes, I can also do what TC suggested and re-shape the steel plate to accept another three 6mm studs - two more from the starter motor cover, and one more from the gearshift cover. Gives a total of seven lock points all isolated from the frame. Also use high tensile rod for all studs.

[pggg]

While in peices, pics here show how simple this thing really is.

1. sprocket
2. bearing race off original bearing
3. collar cut off the original bevel gear
4. steel washer
5. sealed bearing
6. locknut


How it sits on the spline


Left side bearing unit with steel plate

[GNEPIG]

.. solid mounting the motor in the frame would allow you to add your mounting brace to the frame without flexing problems. if you go that way, you might want to step your brace out to hold the end with your left side bearing and steel plate
.. if the bike was geared lower it would cause less flex also, it would be easer for the engine to throw the bike down the road under hard acceleration
this may not be the cure, just throwin out some thoughts here