Transmission noise

[jakeman]

Hi all, sorry if this has been covered somewhere else, but I'm in a panic. I just got back from a 50 mile ride and as I was pulling into the garage I hear this clunk from down below. I put the bike on the centerstand and put it in gear and the transmission is making a terrible clunking sound, sounds like a backlash. It gets progressively worse as you go to a higher gear and in 5th it sounds terrible. The bike ran perfectly and shifted perfectly al afternoon. I didn't know anything was wrong till I pulled into the garage and heard that noise.

If I give it some gas it stops clunking, but when I let off the gas it clunks real hard one time and then settles into a steady clunking sound, so it must be backlashing or something. Btw, the bike only has 7k miles since new.

Please tell me there's a simple fix for this.

Thanks,

[Ken Talbot]

Are you absolutely sure the noise is coming from the transmission? A more common sourse of a clunking noise is the spline connection between the rear wheel and the final drive. If this gets dry, you will get a clunk that can be a bit hard to trace. Remove the rear wheel, coat the spline with a rub of grease and reassemble and that noise will go away.

At such low mileage, it would be very unusual for the transmission to be shot, but a dry spline can happen easily.

[jakeman]

Ken, when the bikes running in gear on the centerstand the noise sounds like it's coming from the transmission. When I put my hand around the drive shaft housing I feel nothing, perfectly smooth. The noise only happens while the enging is idleing and in gear, when I speed up it stops. I just recently changed oil and was hoping the oil (Castrol) I used was some of the problem. I just changed it and put in Valvoline 20W50 motorcycle oil and already I can tell the engine is quieter and the clunking is not as bad, but still there.

It is possible that this could have been going on for some time because I haven't had the bike on the stand and running in gear for a while, and my hearing ain't worth a damn anyway from flying a little Cessna for 40k hours. I just happened to hear that one little clunk while pulling into the garage and started investigating.

Do you think if it was in the final drive like you say, I should be able to feel it in the shaft with my hand?

[jakeman]

Ken, I just pulled the rear wheel and the spline was ok but I greased it up good before I put it back. Anyway, I still have the clunk! It may have been there all along but I doubt it. Does anyone else have this backlash while running in gear on the stand? If I apply a little brake pressure it stops, if I speed up it stops. It's definatley a backlash. What's the cure?

Thanks guys,

[TopCatGr58]

Hey there Jakeman,

Can you explain what 7k miles since new means? Does it truly have only 7kmiles on the odometer, or that you've only put 7kmiles on it since you got it new to you??

If it has only 7K true miles, then I would doubt the primary chain slack, but with some high mileage bikes, folks have reported a clunk that couldn't be explained thru any other component. BTW, have you done the Middle Drive oil change?

The XS11 tranny and drivetrain DOES have a lot of slack in it, and so when under very little load, you can hear a backlash sound easily. The straight cut gears, the space in the dogs/slots, middle gear, final gear splines, all contribute to this backlash feeling when riding, getting on and off the throttle.

So...if you're middle drive has good level of oil, then it's probably a normal sound for your bike!?
T.C.

[jakeman]

T.C., 7k miles is correct, I am the original owner. The bike sat for years and I just started riding it again a couple months ago. The oil in the middle gear has never been changed but the level is where it should be and the oil looks clean. I guess I wont worry too much about it unless it gets worse. I'll change the gear oil, I guess it probably needs it after 24 years.

A question (dumb): does downshifting through the gears cause any damage or excess wear?

Thanks all, if you can think of anything else, I'm all ears.

[GNEPIG]

.. Jakeman, take your bike for a ride then come back and tell us what you heard while cruising around the neighborhood
. also with the bike on the center stand and NOT RUNNING put it in gear, then grab the back wheel and rotate it forward and back. that movement from stop to stop is the free play in your drive line. when your idling in gear on the center stand your wheel has no load on it to keep it from trying to free wheel in that free play space, until you apply the rear brake a little or give it some throttle the wheel is trying to out run itself bucking back and forth from one side of this space to the other.
.. on the street it is different, the wheel is on the ground the ground is the resistance and the drive line free play is taken up by the engine and the clutches when running.. you can feel this free play when you whack the throttle on and off while cruising down the road at lower speeds, this will give you a bucking sensation as the drive line lashes back and forth in the free play space, and you will hear it clunk each time it hits from one side of this space to the other
.. all this is a little noisy and abrupt but it kicks the crap out of adjusting and oiling chains once a month

[jakeman]

Thanks GNEPIG, what you say makes perfect sense, of course, but I could just swear I have never heard that sound before today.

[TopCatGr58]

No dumb questions here!!

Downshifting and using engine compression to assist in the slowing down of the bike to keep stress off of the brakes does not hurt the gears, or cause extra wear on the dogs and slots, cause with the rear wheel pushing the engine, the opposite contact surfaces of the dogs and slots in the gears are engaged and under pressure vs. the edges that are mated when under the pressure of increasing throttle!

However, with regards to 1st gear, it's a known affect in the incidence of rounding off the dogs and slot contact surfaces from rough engagement "Clunking" of the bike into 1st gear from a stop, cause the gears are spinning when the clutch is released in neutral.

Several techniques have been suggested to reduce this damage that accumulates over many years and miles eventually leading to the failure of 1st and 2nd gear to stay engaged. One is to sit at a light with the bike kept in gear holding the clutch in, this is also good cause you're more ready to make an emergency maneuver and can pull away much quicker without having to shift into gear first! After driving, if stopping for a short stop and turning off the engine, then restart it IN GEAR and then take off.
But when you must put it in neutral, holding the clutch in for several seconds before shifting into 1st can help reduce the speed of the spinning gear, reducing the "clunk" affect.

Welcome back after so many years! I got mine with 15 miles on it in 83, so I really consider myself as the only owner, took a 9 year hiatus starting in 92 due to the 1st and 2nd gear malady, got it back on the road in 2001. We're almost neighbors, will have to get together next year some time, hoping to get up there to Maryland International Raceway for some Test and Tune runs!

[GNEPIG]

One is to sit at a light with the bike kept in gear holding the clutch in, this is also good cause you're more ready to make an emergency maneuver and can pull away much quicker without having to shift into gear first!

.. Amen to that brother and to keeping an eye on the mirrors while sitting at the light

[jakeman]

Top Cat, I know what you mean about shifting into first from neutral, I always try to avoid that when I can, don't like that sound!

GNEPIG, I'm with you. I treat everybody I see on the road like I am on the FBI's most wanted list. I am convinced that most people can't see motorcycles, I almost t-boned a pickup that pulled out in front of me about a month ago. You have to stay alert every minute.

Thanks for all the help,

[fxrer]

...then restart it IN GEAR and then take off.

To avoid the horrendous clunk when shifting the trans into 1st, especailly when cold, I always start the bike in gear.

I'll start a cold engine in neutral, then after 30 seconds or so, when running smoothly, I hit the kill switch, pop it into 1st, then restart the engine.

This might be harder on the starter motor, but that is easier to change out than 1st & 2nd gears.

Plus, I can't stand to hear that clunk!

[LoserShoes]

Don't like the clunk either. What I do is just barely start to shift and don't, it gives a bit of a click, which I assume gets the big heavy stuff turning, then shift into first without the big clunk. Takes a little practice to get it right. Might be dependent on the condtion of the gear dogs too. My tranny seems to be in good shape.

Steve

[pggg]

Jake, not a clattery clutch or starter motor is it? Or worse scenario the crank bearings got rough spots from sitting or ran dry for some reason. You'll start to hear a lovely clunking sound then As an aside, all this usually normal clunking, whiplash and snatching on an XS11 is caused mainly from the shaftdrive. On a chain type XS11, the gear changes are quieter and smoother in gears 1 thru to 3 (4 and 5 are smooth enough anyway) and the chain/cush hub eliminates the on/off power snatching that happens sometimes in low gears. Changing from neutral to first still clunks, but nowhere near as bad. If in a queue of traffic, I just switch off, then hit the starter in 1st when ready to roll.

[jakeman]

Thanks for all the replies guys. I've changed all the fluids but haven't tried it out yet. I'll post the results later.