250sx Can't Find The Right Clutch

[Gearheadtom]

So I've been trying to find a centripetal clutch for my '85 250sx. My shoes and stuff are fine, but the drive plate/clutch hub, whatever you want to call it is worn, so even with a new 1-way bearing, my kicker still slipps.
So I've tried two different clutches from two different '85 big reds, and the problem I'm having is that neither fit my crank. The drums are the same, but the splined end of my crank is smaller than the big reds.
Would it be that they're big red clutches? or that maybe my motor is from an '86 sx? I heard they changed the cranks in '86. I tried to find the serial number on my motor, but couldn't find it.

[kebby28]

Well, The sx motor I belive is a little different. I know they are geared a little different. They look identical, but different. What part is worn? I bet you will find what your looking for on ebay.

[6speedthumper]

Hmm... That is interesting. I wonder if the clutch from a TRX300 is the same as yours, or the Big Red...

[Dirtcrasher]

If the journal that one way bearing rides on is not within spec, a new bearing will still slip; I have seen it happen.

Unfortunately, you will need to change that also with a good used one.

So when you shut it off it winds and thunks and the manual kicker also still slips? Then that's the problem.

If the electric start slips, it's the other one way clutch on the flywheel side being the issue.........

[Gearheadtom]

It's the journal that the 1-way bearing rides on. A new 1-way bearing made it able to start with the kick start, but still just barely. The bike got run for a really long time with a bad bearing by the previous owner, causing it to wear the part of the clutch out.
I've looked on ebay, and prices are crazy, plus the shipping to canada. I know the gearing between the big red, and the sx were different, but I figured the cranks and centripetal clutch would be the same.
I know for sure my motor isn't an '87, it has the '85-'86 style starter reduction gears.

I looked it up on bike bandit, and the '85 250sx, and '85 250es have the same crank, but lists the same number for the '86 250sx crank. A parts fiche on a different site lists a different number for an '86.

Where is the serial number on the engine so I can look it up to make sure I know what engine I've got? I had a look for it, but it was in the dark with a flashlight, and the motor is dirty haha

[effort=results]

I got a centrifugal clutch my 87 250es and had same problem in reverse. The center spline was to small so had to switch my center splen from thoriginal with the new pads and outer bell.

[6speedthumper]

[QUOTE: If the journal that one way bearing rides on is not within spec, a new bearing will still slip; I have seen it happen.

Unfortunately, you will need to change that also with a good used one.

So when you shut it off it winds and thunks and the manual kicker also still slips? Then that's the problem. :QUOTE]



My TRX300 4x4 does that^^^. I've been meaning to take care of it for a couple years now... Good thing I have a parts engine.

[Dirtcrasher]

Where is the serial number on the engine so I can look it up to make sure I know what engine I've got? I had a look for it, but it was in the dark with a flashlight, and the motor is dirty haha

It may be on the top rear of the engine lower cases on that model if I recall..........

[Gearheadtom]

I looked again tonight and found the number... it's amazing how much daylight can help haha. My engine number is TE04E-50719140, and according to the specs page on the 3ww old site, it's an '85 motor.
So idk why the clutch from an '85 won't fit. Maybe the crank was swapped?

Does anyone have an '86 and '85 clutch they can measure and compare? I think that might be my only way of figuring this out.

[Gearheadtom]

Anyone have an '86 clutch they can measure for me? I need something to compare to my clutch, so I can figure out what clutch I have. I don't want to buy a clutch for an '86, and find out it doesn't fit.

[Dirtcrasher]

What id/od do you need?

Bear in mind my bones are all broken, so it take me some time....

[Gearheadtom]

What id/od do you need?

Bear in mind my bones are all broken, so it take me some time....

I need the ID of the splined part on the clutch hub/drive plate, where it goes onto the crank. I've gotta track down what clutch fits my bike, '85 clutch (centripetal) won't fit, and I haven't got one from an '86 to try.

No worries man, take your time.