(Solved) Technical but not KX Specific - Clutch Actuator arm not disengaging

[mrhoney]

I hoping for some tips from a very experienced body of folks - but alas it's with my YZ250 (I do have a KX500 too).   I've posted this same question on different forums (not kxriders), but haven't received any meaningful insight.

The clutch actuator arm will not disengage the engine on my 1996 YZ250.

I was hoping for an easy fix, but now I'm stumped.

I have replaced the clutch plates and springs, but it has had no effect on this problem.  I know it isn't a cable problem, because I have grabbed some pliers and pull directly on the actuator arm until it is fully engaged, and the motor will not disengage.

When I changed the plates and springs, I didn't notice anything unusual on the push rod or the ball baring.  There were no groves in the clutch housing, in fact everything looks great. 

Prior to me replacing the plates and springs everything shifted wonderfully, the clutch pull was horendous and finally just wouldn't disengage the engine at all - again not a cable problem.

Any insights into this?

Any input will be very much appreciated.

[bigbellybob]

i had this problem with my old 250r. i put a HD barnett clutch set in fibers and steels with new springs. turned out the barnett plates were just a little thicker than what was in there. i replaced 1 fiber and 1 steel with old ones and it was enough that it worked.

[kaw rider]

i once rounded off my clutch arm. pull the clutch basket plate and see how much travel you get from the rod. and make sure the rod isnt bent or shorter.

[Hillclimb#42]

I once had a gear seize on the shaft in the tranny(on the 500). Effectively taking away my neutral. The gear had to be pressed off of the shaft. It happened after trying the ATF, but not sure what actually caused it. The guy who fixed, said I had alot of goop in there , and gave me a lecture about changing my oil more often. On mine, I had to pull the clutch in, to load it up on the trailor. Not dissing the ATF, just my luck probably.

[Friar-Tuck]

 Mr. Honey,
The washers and spacers are very finicky, the last member that had this problem had swapped position of one washer and one spacer.   Do you have a service manual for the bike?  (Here is an exploded view of the clutch )
http://www.yamaha-motor.com/sport/parts/home.aspx

Tuck\o/

[BDI]

I once had a gear seize on the shaft in the tranny(on the 500). Effectively taking away my neutral. The gear had to be pressed off of the shaft. It happened after trying the ATF, but not sure what actually caused it. The guy who fixed, said I had alot of goop in there , and gave me a lecture about changing my oil more often. On mine, I had to pull the clutch in, to load it up on the trailor. Not dissing the ATF, just my luck probably.

I love it. Why do we not ever hear about this stuff when we are having the atf verse tranny oil debate? Or do I just not hear it because I choose to tune this retadred argument out.

[Hillclimb#42]

I posted that on the ATF thread too, BDI. After 8 pages, its hard to get into all of it. Stewart said to use oil in his motors. Royal Purple is his preference. Hard to explain my transmission troubles, when other guys have used atf for years, and obviously ready to defend their position on it. The thing for me was the atf was not any cheaper for the risk, and didn't convince me it worked better by my own experience, only. I'm not the guy who challenges theories. I'm here to understand them, instead of believing in them without information like I did before I found this site. I really like informed decision making. Lots of technical information about it on that thread, but I'm sticking with 10w30.

[mrhoney]

Mr. Honey,
The washers and spacers are very finicky, the last member that had this problem had swapped position of one washer and one spacer.   Do you have a service manual for the bike?  (Here is an exploded view of the clutch )
http://www.yamaha-motor.com/sport/parts/home.aspx

Tuck\o/

Yes I have a service Manual and followed the instructions faithfully.  I'm going to take it to a mechanic tonight as I'm losing patience with my lack of skill and experience.  I'll let you know what the end result is - as I searched and searched and didn't really see resolutions to items like this where replacing the plates and springs didn't solve it.  It will go into neutral no problem and it still shifts great, just can't get the engine to disengage.

[mrhoney]

Problem was with the pressure plate.  Apparently the short push rod rubbed too much material off the pressure plate, so we placed a custom made spacer to fit behind the ball baring to help push it out further.  Not sure how long this will last, but it beats buying a new pressure plate plus a new short rod for now.  Disengages like a champ now.  It had us scratching our heads for a while because everything appeared to be fine.

Thanks for the suggestions and I'm happy - cost me $70 to have him figure it out, but I can use my machine now and go riding again with my Son which is priceless

[DoldGuy]

Mr Honey,
Thanks for posting the fix as most are too excited about having it fixed & forget about posting the cure. This might help others when they run into problems.
DoldGuy