Topic: Freshening the Top End

[NewOldSchool]

My CB750 with 30,000 miles on it has the ubiquitous head gasket leak (or the rubber plugs in the cylinder head) either way I'm going to pull the motor for a little refurb.

I have a complete gasket set, but my question is this:

Is it necessary to install new "heavy duty" studs, or can I make sure the gasket surface is clean and torque everything to spec?

I am not talking about a total rebuild here, just fixing the minor oil leak from the cylinder head gasket area.

[killersoundz]

A lot of people re use the studs. I am as well.

[NewOldSchool]

Sounds good, didn't know if it was a necessity or just a good thing to do if hopping up the motor significantly.

[HondaMan]

Use HD studs with big-bore kits. There is little other reason to: I have had the top end off many 750s and even bored them to 4th oversize, reusing the studs. No grief!

Check the looseness of your valve guides at that mileage. In particular, if light (10w-something) oils were used a lot in the engine, the guides are usually worn.

[NewOldSchool]

Ive owned it since about 16000 miles and have been using Honda GN4 20w50 in it since.

Having the motor out and the head off is half the job so I might as well do the guides while I'm at it!

[HondaMan]

Ive owned it since about 16000 miles and have been using Honda GN4 20w50 in it since.

Having the motor out and the head off is half the job so I might as well do the guides while I'm at it!

The guides from APE are nice bronze ones. They will fit even a Webcam, as they are slightly shorter than the stock ones.

[NewOldSchool]

Thank you for the advice!

[MCRider]

When the bikes were new, the head gaskets leaked and were often fixed under warranty. We never used the heavier studs.

The leak from the pucks occurs at a level above the head gasket. So you can easily identify either or both are leaking.

Freshening up the head at 30k will make a sweet motor.

[NewOldSchool]

Thanks again,

It looks like its leaking from the head gasket mainly in the area under the exhaust ports, but its enough to leave my kick starter wet and 1/4 teaspoon of oil in the little valley above the clutch cover/points cover every time I ride...

[CrankyOldGuy]

Hondaman or someone else,

Are the torque values given in the Honda shop manual dry or wet torque values?

Harry O.

[MCRider]

Thanks again,

It looks like its leaking from the head gasket mainly in the area under the exhaust ports, but its enough to leave my kick starter wet and 1/4 teaspoon of oil in the little valley above the clutch cover/points cover every time I ride...

Sounds like the head cheeze, but of course you have to replace the pucks to get there.