Topic: very basic engine questions

[Greg]

hey all

planning on working on the engine of my 76 750f this winter.  have low (about 125) compression across the cylinders.  trying to figure out what to do once i have the engine out.  i've been reading the posts, but am a bit unclear as to what exactly the following terms refer to:

1) top end rebuild
is this normally replace pistons and rings, new gaskets, new cam chain?
2) valves -- maybe new guides, take head to machine shop to have them seat the valves?  maybe new springs?

anything else i should do while i'm in there?

sorry if this post is redundant, i'm a bit slow on the engine stuff.

thanks!

greg

[Dennis]

I would need a lot more reason than uniformly "low" compression to get me to rip apart a perfectly good "750" engine.
Why are you taking it apart?
Does it run poorly?
What do you know about your compression tester? Are you sure it just doesn't read low?
What other symptions are there?
What mileage is there on the engine?
What condition did you get the bike in?
I'm not convinced that I would spend the time and money to tear into that engine at this point!

[Quail "Owner of the comfortable k8"]

Why don't you buy another engine and rebuild that one, You can take your time and spend as much as you want and make it as new as you want and still have what seems to be a good engine to ride with until that day comes that other one is finished.  Thats a long sentence!

[eldar]

I guess i dont really see 125 as being low. Now if you were at 100 , then maybe I would look at that as low. You can try putting about a tablespoon oil in the cylinder and try the compression. If it is the same then your rings are fine. If it drops then the rings are starting to wear beyond tollerances.