Any CB750 Supersport Gurus out there?

[jonbuoy]

I've just come back from looking at a CB750 Supersport - SOHC jobby. Engine starts fine but there is an unpleasant slight rumbling and squealing - bearing like noise when the bike is in neutral - clutch in or out. It seems to quieten down when the bike is in gear. Its sounds like its coming from the left hand engine cover. - Any ideas as to how serious this is? Oil light flicked out pretty quick and I didn't smell any burn't oil from the pipe. Only other problem I have seen is an oil leak from the head gasket. I'm OK doing a head gasket but not sure if I want to get involved in big end bearings etc...

I haven't taken it for a test ride yet so not sure what its like on the open road, otherwise it looks tidy for a 20+ year old bike.

Cheers

John

[Bonez]

Post also try posting your quary here John- http://www.sohc4.us/

[jonbuoy]

Thanks Bonz - on my favorites now.

[Bonez]

Thanks Bonz - on my favorites now.You're welcome. I have it's little brother, a Cb550FA. Is it an F1 or F2 John?

[jonbuoy]

Ah I'm not sure - Another thing I forgot to check... It has twin front discs and a single disc on the rear - alloy wheels if that means anything? Still lots of these SOHC around eh? I'm going to turn it into a cafe racer if I get it. Seen some really nice ones around - Crack gave me the idea with his post on classic bikes. Seen a few places selling single seat kits and stuff.

[Bonez]

Ah I'm not sure - Another thing I forgot to check... It has twin front discs and a single disc on the rear - alloy wheels if that means anything? Still lots of these SOHC around eh? I'm going to turn it into a cafe racer if I get it. Seen some really nice ones around - Crack gave me the idea with his post on classic bikes. Seen a few places selling single seat kits and stuff.Cb750F2 by the sounds of it. Engine blacked out is it? F1s had spoked wheels and single front disk and clear laquered engines.

Still a few sohc Hondas about all right.

Cafe 750s here for inspiration ;) - http://www.cb750cafe.com/bikes.php?cat=1&id=21

There's an F1 up for grabs on trade at the moment- http://www.trademe.co.nz/Trade-Me-Motors/Motorbikes/Motorbikes/Classic-vintage/photos/a-83929845/p-32837198.htm

[jonbuoy]

Ah I think its an F2 then, it looks the same as that but with twin discs at the front, shame that one is down south or I would be interested.

[Motu]

My '86 CB750 made a grindy rattle in neutral,I was told it was either the primary chain or clutch can't remember,but it had a new primary.Apparently a common noise and nothing to worry about.









Please get back to us in 3 weeks time with pictures of the engine destruction on your homeward trip with the bike....

[jonbuoy]

Thanks.... It looks like head gasket is an engine out job so will be needing some serious spanner work anyway.

[Bonez]

Thanks.... It looks like head gasket is an engine out job so will be needing some serious spanner work anyway. It'll be nice to see how the project progresses if you decide to get it.

[jonbuoy]

Took it for a spin, nice bike to ride around town. I think the noise is coming from the clutch area, cam chain has a bit of a rattle too. I would have bought it but while it was ticking over on its side stand I the oil light flicked on a couple of times, could have just been low on oil bit worrying though, on the CB750 forum they reckon the oil light kicks in at 5lb or less pressure - pretty low.

[jonbuoy]

I bought it in the end! Compression is a bit down (115-125 cold). Going to rip the motor out to sort the oil leak anyway so I'll check valves and bore while I'm there.

[Bonez]

Keep us informed on progress :yes:

[stag21]

Yea I have a 77 cb750fi supersport picked it up down south island . have done a full strip down ,back togeather now motor going in this weekend after spending 3k on it.ops missis not happy.I say good things cost money.

[Roj]

Yea I have a 77 cb750fi supersport picked it up down south island . have done a full strip down ,back togeather now motor going in this weekend after spending 3k on it.ops missis not happy.I say good things cost money.

Yep, most women cost lots:dodge: