slack in drive trane

[phlips308]

hi,im new first time in a forum.i just inherited an 80 xs1100.needs some work.i am mechanically Savoy.was an auto tech for 10 years and now work at a cnc machine shop,cadcam programmer/operator.lathe is my spot,but i have a lot of time on the mills.ok ive spilled my guts.my question is about the middle drive.this bike seems to have some weird slack in it.it seems to bump a little when the torque is applied.the finale drive seems to be ok.if there was slack,what would be a common thing to have symptoms like that?when it is on the center stand,and in gear it has i think excessive back lash some where.it has 54,000 miles on it.among other minor problems.the engine runs good when the floats aren't gas logged.m not sure if what im feeling is the one the inconsistent cylinder coming alive.any advice would be appreciated.mean wile i will start checking the middle gear box.

[Yahman]

This thread might help.

http://www.xs11.com/forum/showthread.php?t=24817

Larry

[phlips308]

hi,im new first time in a forum.i just inherited an 80 xs1100.needs some work.i am mechanically Savoy.was an auto tech for 10 years and now work at a cnc machine shop,cadcam programmer/operator.lathe is my spot,but i have a lot of time on the mills.ok ive spilled my guts.my question is about the middle drive.this bike seems to have some weird slack in it.it seems to bump a little when the torque is applied.the finale drive seems to be ok.if there was slack,what would be a common thing to have symptoms like that?when it is on the center stand,and in gear it has i think excessive back lash some where.it has 54,000 miles on it.among other minor problems.the engine runs good when the floats aren't gas logged.m not sure if what im feeling is the one the inconsistent cylinder coming alive.any advice would be appreciated.mean wile i will start checking the middle gear box.

two wheels gets me there!

[phlips308]

gear problems

its really starting to look like the 1st,and 2nd gear problems that are listed here on xs11.com.i had this happen on my 88 xr600 dirt bike.but the shift fork was also bent.im wondering if this could be the case on this xs1100.im imagining the post on the gears are rounded off like the pictures on this site.i like the idea that it can be fixed without pulling the engine,although im meticulous about things.would probably want to overhaul,or at lest re ring it if i pulled the engine.i overhauled a 72 cb750 once.the crank journals were marked in Japanese characters.was interesting.i lean toward Honda's.my favorite bike is my 88 xr600.my a couple of friends have yz450f's, my xr600 chews them up.im really starting to like this xs1100.

[MindWebs]

here is the manual for the driveline FD.

ShaftDriveManual.pdf
http://www.megaupload.com/?d=42QVZYLC

perhaps it can shead some light on things/ tolerances.

[phlips308]

thanks for all the help.

[TopCatGr58]

Hey Phillips,

Before you decide to redo the topend, as well as the bottom end, you'll want to investigate the availability...or NON of the required parts. Yamaha doesn't support their old machines....and you can't get standard oversized pistons anymore. The rings are also a bit difficult if not just $$$!

Have you done a compression test? 54K isn't necessarily bad mileage if it wasn't hammered to death! Folks have put 100K on these machines. I rebuilt the top end on mine due to neglect, rust in the cylinders, but didn't touch the bearings. Have some 16K + on the rebuild with big bore kit and running strong, had some estimated (odometer died at 970 miles, just used tripometer for gas) 50k miles when I did it. The bearings are also $$$.

So...working on the tranny is a good idea IF it's really your problem. These things have square cut gears, and with the drive shaft and middle drive, there is considerable backlash in the driveline! You say the final drive is okay, so I'm assuming that you've taken it apart from the swingarm to inspect the drive shaft splines and clean/regrease them..the ZERK fitting does nothing there!

T.C.

[XS1100_OEM4ME]

Welcom!

OK, when you say "slack" are you talking about noise or what? These drive trains are strong, but lack of hypod oil change or other neg. could cause porb. Your other porb. mis in one or two cyl. is prob ign. prob. Spark plug color check could help find. Bike on center stand, in gear, not running, move the rear wheel, if you have "slack" in your final or mid, you will feel. hear it.

[fredintoon]

hi,im new first time in a forum.i just inherited an 80 xs1100.needs some work.i am mechanically Savoy - - -

Hi Phil and welcome,
from context, you are not a clockwork cabbage but are mechanically savvy. Gotcha.
If this is your first experience with a shaftie, be aware that some driveline slack is usual. Or is this worse than that?
Or could it be 2nd gear starting to let go?
If it seems like one cylinder is cutting in and out, check the pickup coil wiring.

[phlips308]

positive its the 1st gear,i looked at the thread about fixing the dogs on the gears.i fixed the carbs,it runs like a mad cheetah now.if i get on it in 1st i can feel the gears separate,same as my xr600 did. i wished i new that when i tore into my xr600.it had the dogs where rounded like the ones in the trans repair post.it also had a bent shift fork.that fix would have saved me about $300.00.is there a chance the shift fork could be bent in the xs1100?,oh yea i read something about moving a thrust washer to help hold the union together,does this sound right.the exploded view i looked at didn't show a thrust washer on the shaft there.and where is a good place for a u-joint for the cardan joint?

thanks for all the help

[XS1100_OEM4ME]

1st?

1st gear is not norm a prob? 2nd, due to abuse and and not kicking it like a russan tractor when you shift, can kill the dogs on the gear (dremell fix on here for that) Is she slipping out of 1st under load?

[phlips308]

yes,when i accelerate,i can feel it slip out.Ive learned it was treated roughly.it was originally a police bike in Nevada.and the guy i got it from let his teenager ride it a few times.it doesn't come completely out but it feels like its skipping.other gears are good,i haven't been hard on it,i want to give it a good check out first.i need to get at least one float,but going to kit all of them with new floats.

[XS1100_OEM4ME]

skipping?

yes,when i accelerate,i can feel it slip out.Ive learned it was treated roughly.it was originally a police bike in Nevada.and the guy i got it from let his teenager ride it a few times.it doesn't come completely out but it feels like its skipping.other gears are good,i haven't been hard on it,i want to give it a good check out first.i need to get at least one float,but going to kit all of them with new floats.

So doesnt come out of 1st, clutch holds under hard excel under all gears, no slip? Evean with teenage rider, 1st has to be engaged when take off, burn out or wheely, still engaged. Some 1st gear prob have been caused by way to high idle or clutch drag, but few. You may have to open the case and see what is up. Any chunks in oil when changed?

[phlips308]

first feels ok until i accelerate hard.might be the clutch,but most thins ive had with a slipping clutch,doesn't slip and grab like 3 or 4 times until i shift into 2nd.but im open minded.im sure the clutch is quite used.as far as i know measuring the disks with a mic is how a person should check the clutch.ive seen car clutches act similar from centrifugal force,but the physics of a bike clutch are different in my eyes.

[TopCatGr58]

Hey Cherokee,

OEM...have YOU checked out the tech tips, tranny fix ? ...the 1st gear dropping/skipping out is reported there as well as the 2nd. Both are used a lot, and they both can and will wear, sometimes to the point of the skipping problem.

Clutch slippage is usually found in the higher gears, 4th or 5th at higher rpms, 5-7 k, under hard throttle, you'll notice the rpms suddenly rise, but the bike doesn't go any faster! That's the sign of worn plates or weak springs, or both!

The shift fork "might" be bent, but if you can shift it into 1st, then it's there. The problem that often occurs is that when the skipping problem is discovered, they(PO's) also discover that if you HOLD the shift lever DOWN it helped keep 1st in gear. But that put a soft aluminum fork against a case hardened spinning steel gear....which do you think will wear the quickest! So...sometimes you find shift forks with excessive side wear on the actual fork sections more so than actually being bent! Hopefully the PO's son didn't learn that holding trick, or didn't get much time on it to abuse it enough to damage the shift fork?

It's highly recommended to REPLACE the clutch springs with HD ones, even if they are found to be within spec length because they just loose their tension and strength rather quickly being under constant compression. That alone can fix most clutch slippage problems. Other techniques include new frictions, adding extra steel plate, or shims under springs, etc.!