the head and jugs are off.

[rgierer]

Ther bike is a 1918 GS550 with about 30,000 miles. I bought it 3 years ago after it had been sitting for 14 yrs. After the typical rebirth oefforts I had a bike that would run but make all kinds of clatter. Far betond the normal range. I replaced and repaired cam chain tensioners and hoped that would pay of but no dice. I tried everything I could come up, I have pulled everything but the oil pump.

Now I have the head off and and assessing what really needs to be done before I reassemble and how much can I do myself. I am ready to buy a tool to take the head apart but I am no real clear with how exacting the work is in cleaning up the valves. I clearly do not have a machine shop and if that is what I need maybe I need to take the head there first.

There is no smoking gun so far on this bike. I am just going through waht I have to see if whatever is making all this noise will stop.

So, can I do this head myself or s I need to send it off to strangers?

[chef1366]

Click here

[rgierer]

that was very helpful.

But what is this?

I lapped the valves with some Permatex lapping compound. Instead of using a lapping dowel I used a piece of vacuum line and attached it to the valve stem and worked it back and forth in the palm of my hands while pulling up.

Thanks

r

[chef1366]

With the head off and the valve springs removed insert the valve that you are going to use in that port. Using I think 1/4" vacuum hose attach it to the end of the valve stem and spin the valve back and forth with the vacuum line in the palm of your hands. (With the lapping compound on the valve seat)

[Billyboy]

So that helps it to seat?

[Nessism]

So that helps it to seat?

Lapping is okay to do to check/clean the contact surfaces of the valves and seats but it is not a method to recondition the parts. In fact, Suzuki warns against lapping in the factory service manuals. The only proper way to recondition the parts is by have them ground with suitable cutters. Replacing the valves with "good ones" is another option but obviously not appropriate for the seats. Another thing to be aware of when rebuilding an old head is the condition of the valve guides. If the guides are worn the valves will wobble and not seal properly, or for long. Often times the guides will be okay as long as the valve stems are not worn - at least on the 8 valve engines. The 16 valve engines use rocker arm which puts more side load on the valve/guides thus they wear faster but since the valves are smaller, and there are more of them, this does not seem to be a major concern.

Good luck.

[mcycle-nut]

Lapping is okay to do to check/clean the contact surfaces of the valves and seats but it is not a method to recondition the parts. In fact, Suzuki warns against lapping in the factory service manuals. The only proper way to recondition the parts is by have them ground with suitable cutters.

I was a little confused about this statement, as according to the factory manual for the '77 750, it goes on and on about how to lap the valves, even showing a picture of a finger applying "valve compound" to a valve! I then checked the 1100 factory manual, and it does say "DO NOT use lapping compound after the final cut is made." [-( Guess it depends on what bike you have.
By the way, don't use valve lapping compound on Honda 50's either. ;-)

[Nessism]

I was a little confused about this statement, as according to the factory manual for the '77 750, it goes on and on about how to lap the valves, even showing a picture of a finger applying "valve compound" to a valve! I then checked the 1100 factory manual, and it does say "DO NOT use lapping compound after the final cut is made." [-( Guess it depends on what bike you have.
By the way, don't use valve lapping compound on Honda 50's either. ;-)

Lapping compound is fine for what it is, problem is people use it wrong. Maybe Suzuki came to realize this and took it out of the manual? Not sure.

[kent]

I have rebuilt and done valve jobs on probably hundreds of engines in my life time, the only thing lapping does is verify the sealing angles of the valves, nothing more, it is not a machining process or anyhting else. The lapping compound is just basicly a gritty substance that leaves a mark on the valve where contact is made to verify the seat angle and width.