'62 CB72 Clutch Slipping

[ojwilliams1]

This is a '62 CB72 I bought a little over year ago at a good price as it was partially restored but the owner had acquired other bikes that he wanted to concentrate on. After LOUD MOUSE helped me get the carburetors sorted out, I replaced the ugly (metallic burgundy!) paint job with stock colors and since then I've been riding it a lot. The more I ride the better it runs so it's time to address the clutch that slips at full throttle especially when cold.

First, it appears to have five of the newer (ideal?) “-020” aluminum core friction plates that are in good shape (3.71 – 3.75 mm measured thickness). The steel plates also look good but the “A” plate is the same thickness as the “B” plates (1.6mm) so I’ve ordered a thicker (2.1 mm?) “A” plate (22321-GHB-811) on eBay.

The springs are .115” wire and measure 750” O.D x 1.255” long. I’m thinking these should be replaced but there’s a wide variety of opinions on what springs to use. LOUD MOUSE are you there? What’s your latest recommendation and where can I get them? Other opinions welcome.

[LOUD MOUSE]

I'll need to measure the ones I use that are from the Cush Drive clutch.
Someone has replaced the plates but not the center hub or pressure plate.
The design of these has a different way to use/expel the oil and should be what you need after you clean the parts.
If you would call me at 830-895-0654. .............lm

This is a '62 CB72 I bought a little over year ago at a good price as it was partially restored but the owner had acquired other bikes that he wanted to concentrate on. After LOUD MOUSE helped me get the carburetors sorted out, I replaced the ugly (metallic burgundy!) paint job with stock colors and since then I've been riding it a lot. The more I ride the better it runs so it's time to address the clutch that slips at full throttle especially when cold.

First, it appears to have five of the newer (ideal?) “-020” aluminum core friction plates that are in good shape (3.71 – 3.75 mm measured thickness). The steel plates also look good but the “A” plate is the same thickness as the “B” plates (1.6mm) so I’ve ordered a thicker (2.1 mm?) “A” plate (22321-GHB-811) on eBay.

The springs are .115” wire and measure 750” O.D x 1.255” long. I’m thinking these should be replaced but there’s a wide variety of opinions on what springs to use. LOUD MOUSE are you there? What’s your latest recommendation and where can I get them? Other opinions welcome.

[DJM]

I've been in exactly the same place with my CL77, however this is a full 347cc motor so putting out a bit more power that a CB72 (stock engine) version

Like you my clutch would slip occasionally but usually when NOT fully warmed up but I would expect 'my' clutch to cope OK with the power of a 250cc motor

Mine had the same components in as yours except it already had the thicker 'A' plate installed, however the (stock, as far as I know) springs in mine are a little longer at 1.28" so perhaps yours have settled a bit. Wire gauge is the same.

It's hard to be sure from your picture but some of the steel plates look to have 'hot' sections on them which suggests that they may not be dead flat, an essential for a good clutch.

When assembled the plates need to be so flat that the oil sticks them all together to the point where they have to be pulled apart, anything less isn't really good enough.

LM helped me to sort mine out, hopefully he will do the same for you.

[ojwilliams1]

Called LM and as with many before me he solved my clutch problem with advice and parts recommendations. I still have the old clutch parts shown in the original post. I hate to just throw these parts away but I'm not a pack rat so I don't want to just keep them around. I'd be willing to send to anyone who wants them for shipping cost (except the snap ring and and lifter piece/oil guide parts) . It would fit in a medium USPS flat rate box for $13.60 shipping. If you're interested give me your zip code and I will try to ship for less.
OJ Williams
New Orleans, LA

[LOUD MOUSE]

I'd like all the disc and spring/bolt parts.
78028. ...............lm

Called LM and as with many before me he solved my clutch problem with advice and parts recommendations. I still have the old clutch parts shown in the original post. I hate to just throw these parts away but I'm not a pack rat so I don't want to just keep them around. I'd be willing to send to anyone who wants them for shipping cost (except the snap ring and and lifter piece/oil guide parts) . It would fit in a medium USPS flat rate box for $13.60 shipping. If you're interested give me your zip code and I will try to ship for less.
OJ Williams
New Orleans, LA

[ojwilliams1]

Discs, springs, bolts & washers are on their way to you. Should arrive Wednesday or Thursday.
Postage: $8.65

[LOUD MOUSE]

Do you use PayPal?. ................lm

Discs, springs, bolts & washers are on their way to you. Should arrive Wednesday or Thursday.
Postage: $8.65