[mpcycledesign]

This is an 81 CX500 - I have Murray carbs and I just changed the entire clutch assembly. Bike runs and revs excellent - when I put the bike in gear and give it gas - the engine revs (RPM's go up) - but the bike doesn't go anywhere. It seems to bog down in gear. Bike has been in storage for a couple years and it ran fine when I took it off the road. I cleaned the carbs and as I said - changed the clutch assembly. I'm vexed - any suggestions would be greatly appreciated!

 

[reclinedrelic]

This is an 81 CX500 - I have Murray carbs and I just changed the entire clutch assembly. Bike runs and revs excellent - when I put the bike in gear and give it gas - the engine revs (RPM's go up) - but the bike doesn't go anywhere.

First suspect when the engine revs but the bike doesn't go is clutch free play. Did you adjust the clutch for about 20 mm free play measured at the end of the clutch lever, between the ball and hand grip.

It seems to bog down in gear.

Does "bog down in gear" mean that the engine doesn't rev?

 

[mpcycledesign]

Yes - clutch free play is fine but I'll check again. The engine does rev when it's in gear - but the bike doesn't go anywhere (it goes but it feels like it takes a long time before speed matches rev). I have another CX that has the exact same set-up and runs fine. I was convinced it was the clutch until I changed out the entire basket - can't think of what else it could be. I appreciate your feedback and questions - I'm all ears.

 

[mpcycledesign]

Well - I had high hopes - repositioned the clutch able and adjusted the free play but I still have the same problem. Everything is fine until I engage the clutch and give it gas. It revs but the bike's speed takes time to ramp up to the rev. Going up a hill exaggerates the problem. Only other thing I can think of is to get new clutch discs but the 2 sets I tried didn't have much wear on either set. Any other suggestions?

 

[DouginEasternWashington]

Double check you installed all of the clutch plates and that they are in the right order. What oil are you using? Oil with friction modifiers can make a clutch slip. Have you measured the springs?

 

[mpcycledesign]

I have the heavy duty springs - oil is 10/30, nothing synthetic. I didn't measure them but I have a couple sets of springs and they're all the same length. Before I rip it apart again I'm going to get new clutch plates. Doubt it has to do with the order as this ran a couple years ago no issue - but I'll check the order again when the new plates arrive. Thanks!

 

[Randall-in-Mpls]

Is the cable moving freely?

 

[Sidecar Bob]

The following was posted going on 20 years ago on a long gone forum by Dr. Don (now on the Australian CX forum). It is still the best description I've seen of the relationship between clutch arm position and the condition of the plates.

The clutch in a CX500 shows its wear-state by the angle of the actuator arm on the right-hand side of the motor - but it's probably the opposite to what you would expect - the arm is about 20 degrees UP when the clutch "pack" is new, and it gets to about 20 degrees DOWN from horizontal when the plates are nearly worn out. If it gets to about 30 degrees below horizontal, then you will probably find that the pressure plate has "bottomed-out" on the clutch centre, and the plates will spin freely with no pressure on them at all. Usually, by the time your wear has progressed to the 20 degrees down, you have a very bad case of clutch slip.
As the clutch plates wear, you have to screw IN the adjuster on the handlebar lever mount to compensate.
All this assumes that you have the correct thickness gaskets between the front cover and the crankcase, between the clutch cover and the front cover, and that the normal thrust washer/spacer has been used at the rear of the gearbox input shaft.
The other way of telling the state of wear when you are assembling a motor, is to measure the total height of the clutch "pack" - the distance between the pressure plate face and the clutch centre face where the friction discs bear - and it should be 33mm or a little more for a new "pack", and if you find it's 31mm or less, you'll be looking for some new friction plates really soon, if you don't go out and buy some before the motor assembly goes any further.

 

[mpcycledesign]

Is the cable moving freely?

Yes - cable moving freely.

 

[mpcycledesign]

The following was posted going on 20 years ago on a long gone forum by Dr. Don (now on the Australian CX forum). It is still the best description I've seen of the relationship between clutch arm position and the condition of the plates.

Thanks Bob - by the looks of it - I would guess the arm is in the 5% up position by just eyeballing it. I do have new friction plates and springs on order so I'll know for sure if anything was screwed up with any of the clutch part sequence when I open it back up again. Can't think of what else it could be but it's killing me not to have it back on the road again!!!