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CB72-77 Racer

CYP77 - Police | Race Bikes | Choppers, Bobbers and Mods
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CharlesM
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Post by CharlesM » Mon Jun 01, 2015 4:34 pm

Where are you based with this one? I was looking at buying this too having just bought a cb72 racer off eBay (fancied one more!). Mine runs but looks to have been built for parade. It'll be good to have these on the track together soon!

lloydy1
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Location: North Wales

72-77 engine strip down

Post by lloydy1 » Fri Jun 19, 2015 10:03 am

Started the strip down of the engine and this is what I have so far.

The bores measure 64mm with very little wear at all.
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G-Man
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Post by G-Man » Fri Jun 19, 2015 11:01 am

dave

Thanks for the pictures. Looks like a hand-modified CB72 (250) head with modified pistons from a CB350. The bore should measure 64.25 with those pistons. Valves look to be standard.

G
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160
'66 Matchless 350 '67 CL77
'67 S90 '77 CB400F

lloydy1
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Post by lloydy1 » Fri Jun 19, 2015 11:57 am

G-Man wrote:dave

Thanks for the pictures. Looks like a hand-modified CB72 (250) head with modified pistons from a CB350. The bore should measure 64.25 with those pistons. Valves look to be standard.

G
Hi G

So it is a 350 then? little disappointed with that...wounder what is going on with the numbered fairing then?

Ive yet to split the cases, so we will see what is going on in there.

Cheers Dave.

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G-Man
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Post by G-Man » Fri Jun 19, 2015 1:00 pm

Well to be exact 64.25 x 54.0 gives 350.15cc

I would think it would be still classed as a 350.

It might have a long-stroke crank but you would probably find a plate under the barrel if that was so.

Looking forward to your next installment.

G
lloydy1 wrote:
G-Man wrote:dave

Thanks for the pictures. Looks like a hand-modified CB72 (250) head with modified pistons from a CB350. The bore should measure 64.25 with those pistons. Valves look to be standard.

G
Hi G

So it is a 350 then? little disappointed with that...wounder what is going on with the numbered fairing then?

Ive yet to split the cases, so we will see what is going on in there.

Cheers Dave.
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160
'66 Matchless 350 '67 CL77
'67 S90 '77 CB400F

lloydy1
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Posts: 66
Joined: Sun May 24, 2015 2:29 am
Location: North Wales

Post by lloydy1 » Fri Jun 19, 2015 1:14 pm

The con rod has S280 stamped in the side of it. Don't know if that has any meaning to be honest.

I now thinking what gasket set would I get for the rebuild. Would it be a 305 CB77 Superhawk 1961 1962 1963 1964 1965 1966 1967 Engine Gasket Set?

sorry about all the questions I'm new to this engine and with it being none standard.

Cheers. Dave

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G-Man
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Post by G-Man » Fri Jun 19, 2015 4:16 pm

Dave

Most of the gaskets would work but you would need to get a 64mm head gasket.

http://bore-tech.com/product/head-gaske ... g-bore-kit

G
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160
'66 Matchless 350 '67 CL77
'67 S90 '77 CB400F

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