SOHC.co.uk Forums > CB750
Broken clutch lifter plate... What next?
cbxman:
--- Quote from: Trigger on June 14, 2022, 07:48:55 AM ---There are two lengths of springs fitted to the 750. Early ones were short with a thicker dia coil. Later springs are longer with smaller coil ;)
--- End quote ---
Trigger,
Thank you.
Being an American import, this bike could have anything in it!
I have measured the springs that are in it. They are 35.5 mm long, with 8 turns of 2.6 mm of wire. Extremely hard to compress by hand. There's a company called Barnett (sp?) and they produce performance parts. Their take on the 750 is springs 36 mm long with 2.6 mm wire. I think those springs are the hopped up ones. Apparently stock Honda springs are supposed to be 31.75mm with 2.54mm wire.. A lot shorter with thinner wire.
Also....Studying the release mechanism a bit more, I noticed that the release bearing was not seated in the release plate. About a 1mm short of seated. The release cup which fits into it was not seated either. They were solid I had to press them out. I cleaned the faces, greased them and pressed them back in to seated. How did that happen? They must have been like that from factory. I have been trying to figure out what that might mean in terms of clutch performance....maybe nothing other than the adjuster screw might be set further out than normal.
The interaction between the face of the release cup and the release mechanism is unclear. The adjuster screw seems to just push the release bearing away, which means the face of the release mechanism isn't running against the flat portion of the mechanism...may be that's how it is.. with the nose of the adjuster screw running in the bottom of the cup rather than the flat faces of the two
Baffled, and apologies for the waffling....
Jerry
Trigger:
As i have already stated, Honda had two types of springs in the 750 and you will not find it in the manuals. Yours are the later type ( longer with thinner wire) . The K6 clutch is the same as the F1 clutch with a double plate.
Early spring fitted to the K1 was 32.50 with a 2.92 wire.
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cbxman:
Thanks Trigger,
More confused now.. Hondaman was staying 31.75 with 2.54mm for the early clutches.
However, my bike is a K1, built Nov 1970. The clutch could be from anywhere after 50 years, so you could be right, and maybe the UK market and US markets had different setups, although the parts book would have you believe there are no differences.
I guess I'm at the mercy of whoever supplies the springs. I suppose I could use the current ones. They are almost exactly the same as each other, although intended for the later clutch.
Ho-Hum,
Cheers,
Jerry
Trigger:
It all depends on what spring hondaman is measuring :o
CB750 K0 to K6 springs were superseded so many times ;)
22401300000
22041300000
22401368000
9501475140
22401275000
22401369000
cbxman:
Trigger,
He was measuring an early Honda item and a Barnett item.
See:
http://forums.sohc4.net/index.php/topic,182424.msg2115426.html#msg2115426
Jerry
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