250R clutch spring length

[pismorat]

How crucial is clutch spring free length? My new '85 250R shows a service limit of 45mm; I am measuring all of them to be around 42-43mm. The plates and discs all look great, but should I keep running these springs or replace them?

[El Camexican]

I suspect you are just fine to use them. I've seen new springs and plates from Yamaha, Kawasaki and Suzuki that were out of tolerance from new (I don't do Hondas). I don't even check them, or the steel plate thickness anymore. Just check the steels for warpage, the fibers for cracks and wear and put them together. I will add that all springs, fork, shock, clutch, car, whatever, lose a bit of height, or length when first used, this is a property of any stressed steel, but after the initial loss they don't move much. Yours have likley been in a clutch for 25 years, so it is normal they would lose a bit of length having been in a compressed state so long, but as long as you are not building a 100HP drag racer, you should be fine and if you were building one you would likley want different springs anyway. One last thing. Make sure you put all the steel plates in facing the same way. That is to say there is one very flat side and one with rounded corners. Typicaly the rounded corners face outward in the stock clutch to facilatat easy of opening the clutch, but on a drag race engine I face them it to allow the steels to "slide" into place as easily as possible. You can go either way, but make sure they are all facing the same way.

[Dirtcrasher]

If the spec is 45 and your at 43, you are 2MM short or roughly .080 or "eighty thousandths". Yes springs get weak, but why not spend the short amount of money to fix them before your discs start slipping; then it's a 120$ OEM repair....... Get some Barnett springs.

42MM is a bit less than 3 dimes stacked up...

[rdlsz24]

If you already have it apart you might as well put new springs in. They only add $20 to the job:

http://cgi.ebay.com/ebaymotors/Honda-ATC250R-85-86-Barnett-Clutch-Spring-Set-/150521289028?pt=Motorcycles_Parts_Accessories&hash=item230bc49944

Those aren't HD springs so the lever pull feels like oem

Rob

[El Camexican]

42MM is a bit less than 3 dimes stacked up...

Did you mean "2mm" is like 3 dimes stacked? Cuz 42mm is about 1.65". If you want to change them go ahead,, new parts never hurt anything. I wouldn't, but if you do I suggest you avoid HD springs as 24 suggested.

[Dirtcrasher]

If you already have it apart you might as well put new springs in. They only add $20 to the job:

http://cgi.ebay.com/ebaymotors/Honda-ATC250R-85-86-Barnett-Clutch-Spring-Set-/150521289028?pt=Motorcycles_Parts_Accessories&hash=item230bc49944

Those aren't HD springs so the lever pull feels like oem


Rob





THANK YOU Rob!!

Yes I made a mathematical error, however, I suggested the proper solution based on specifications in the manual........ :D

42MM is 3MM less the 45MM spec, and about 3 dimes stacked up. Hope that clears things up :beer

[El Camexican]

THANK YOU Rob!!

Yes I made a mathematical error, however, I suggested the proper solution based on specifications in the manual........ :D

42MM is 3MM less the 45MM spec, and about 3 dimes stacked up. Hope that clears things up :beer

I figured that's what you meant. With respect to the spring length I'll just mention that I've received new clutch springs that were under tolerance before using them and that I suspect if you did have a full 45mm new spring and put it into service for a couple months you would find that its free lenght would be a few mm less that what you started with. That's just how steel under stress works and the good thing about that is after the initial "de-stressing" they tend to last a long time, especialy in a 2 stroke clutch VS a 4 stroke valve spring that is moving thousands of times per second at high temp. I hope he measures the new ones measure when he gets them (if he goes that route) and tells us how long they are, I'm interested to know. :beer

[pismorat]

I think I am going to keep the current ones for the time being. I have to do the top end still, and there are some other odds and ends to make sure the thing will even run first. I can always do the clutch springs at a later date since its a pretty simple job. Thanks for the help!