• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

Cylinders - To hone or not to hone, that is the question

  • Thread starter Thread starter williampkerr
  • Start date Start date
W

williampkerr

Guest
I'm overhauling the top end of my '81 GS850G that has 30K miles. I've removed and inspected the cylinders. They are definitely smooth (some people will say they are "glazed", which my definition of the word 'glaze' isn't an accurate statement, but I digress) and the cylinders don't appear to have any gouging or imperfections. I've read conflicting opinions about honing cylinders. Some say yay and some say nay. What does this trusting community of GS riders have to say on this matter? To hone or not to hone, that is the question.
 
Definitely hone the cylinders. The rings and cylinders have to wear together to make a good seal. If you turn the rings in the grooves (as you inevitably will), the rings will no longer line up exactly the way before you took apart the engine. Honing the cylinder with a flex hone ("ball hone") breaks the glaze and creates a new cross hatch in the cylinder walls. The rings and cylinder walls can now wear together to make a new mating pattern.

Not hard to do and the hones aren't expensive. This link looked good.
http://www.enginehones.com/technical.html
 
AJ said:
Definitely hone the cylinders. The rings and cylinders have to wear together to make a good seal. If you turn the rings in the grooves (as you inevitably will), the rings will no longer line up exactly the way before you took apart the engine.
Click to expand...
Sorry to say but the rings in an engine never stay stationary.

Two strokes are pinned so they can't but 4 strokes can and do.
 
The key would be to" lightly" hone the cylinders,just enough to break the glaze and get a cross hatch pattern.
I have seen them honed nearly to the next over size.:eek:
 
850 Combat said:
Just curious, why take it apart at only 30000 miles?
Click to expand...

I'm new to working on motorcycles, so I'm learning as I go. I did a wet and dry compression test and noticed the compression rise with the wet test. 1 and 4 cylinders where about 80 psi while 3 and 4 cylinders were about 120 psi on the dry test and each rose about 20 psi on the wet test. A friend suggested I inspect the cylinders and rings and valves, which I'm in the process of doing as we speak.
 
williampkerr said:
I'm new to working on motorcycles, so I'm learning as I go. I did a wet and dry compression test and noticed the compression rise with the wet test. 1 and 4 cylinders where about 80 psi while 3 and 4 cylinders were about 120 psi on the dry test and each rose about 20 psi on the wet test. A friend suggested I inspect the cylinders and rings and valves, which I'm in the process of doing as we speak.
Click to expand...

Did you check the valve clearances before taking it apart?
Poor compression is almost always due to neglected valves.
 
Has it been standing? If so, how long?
Riding the snot out of it for a while will bring those numbers up if she has been idle.

And yes, Dale is spot on, rings do not stay stationary in the pistons, they rotate in the ring grooves all the time, so it is of no consequence how the rings are fitted.
I have seen people spend silly amounts of time tryingto stagger the ring end gaps perfectly, just wasting their time.
After the first two minutes of running, those ring gaps are no where near where they were when installed. :rolleyes:

But, yes, hone for sure, if you doing a top end refresh, don't do a half job, also thought it was a typo, at 30 000 miles the motor is only just run in now.
 
tkent02 said:
Did you check the valve clearances before taking it apart?
Poor compression is almost always due to neglected valves.
Click to expand...

I didn't check the clearance before taking it apart. The valves definitely needed cleaning though. I have cleaned them and they appear to be in good condition.
 
Flyboy said:
Has it been standing? If so, how long?

But, yes, hone for sure...
Click to expand...

She has been non operational for 10 years or more. I figured that honing the cylinders and lapping the valves was good general maintenance on this bike that is 33 years old. Either way, I'm knee deep in it now. Any other suggestions while I have the top end dismantled?
 
Yes, too bad, giving it a good hard ride would have brought those compression numbers right up to where they need to be, but like you say, in to it now.
Don't cheap out on the base gasket, you really don't want to pull it all apart again due to a base gasket oil leak a year down the road, and the cheap ones tend to do that.
Other than that, it is all pretty straight forward, not a difficult job at all, post updates so we can follow the progress.. :D
 
I used to hone but it is better not do to it. But it is your choice.
 
You must log in or register to reply here.
Back
Top