• 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.

Question about GS750 motor

  • Thread starter Thread starter pasteurized
  • Start date Start date
P

pasteurized

Guest
A buddy of mine just picked up a '79 GS750 and we were messing around with it a little today. The motor was a little stuck but some penetrant spray and a few minutes later, it was turning over just like my 750. Except it will not turn 360 degrees. I can turn it roughly 180 degrees with it in neutral or with the clutch on, but no further. I would think that it should turn over indefinately. What would make it stop in either direction? We have not tried to start it with a starter yet, I want to make sure the motor is ok first. We tried to turn it over via the 19mm nut under the timing cover. What gives?
 
I would put some marvel mystery oil in the cyl & let it soak over night
If that doesn't help I would check & make sure that a valve is not stuck open
 
It does sound more like one or more valves is stuck open for some reason (bent stem? rust?), or maybe the cam chain skipped with all the horsing around.

I'd pull the valve cover and see if the cam chain is moving and the cams are timed correctly. Stuck valves, if any, should then become evident.

Hopefully if it's mistimed it didn't happen while the engine is running.
 
I guess this is where my lack of knowledge of engine internals shows. Why would a stuck valve keep the rotating mass from turning? The carbs, exhaust, and plugs are out of the motor (and carbs and exhaust have been off for roughly a year, as it has been sitting outside in the weather, that sort of bugs me). Emptied the oil to move the bike and it was half oil, half water. Can't be good. All of the plug holes have been filled with deep creep (that's what we have) and it has been sprayed liberally in the exhaust holes, and the "intake manifold" as well. I don't want to deal with rebuilding this motor. Let's say tomorrow comes and it is still giving me problems. What are my options for action? I haven't tried really cranking the motor hard via the crank bolt under the timing cover, should I give it hell in hopes it breaks something free?
 
engine

engine

Bad news the motor is junk, find a new one :( :(
 
If you found water in the crankcase/transmission, the damage due to rust & corrosion HAS to be considerable. Gears, bearings, shafts etc. will have rusted beyond any hope of repair.
If you have the time & tools, take it apart & see for yourself. Be warned - It won't be a pretty sight!

Terry
 
junk

junk

water and oil seperate so what was in the crank case has rusted every thing not covered by oil, not good, outside for a year with no carbs and exhaust equals water in the cylinders witch is more than likely the cause of the crankcase having water in it, rusted cylinders witch wont hold compression due to pitting and other damage to the cylinders, if a valve is causing the lack of full rotation its because the piston is hitting the valve, or, there is so much rust in the cylinders that it is hitting a large rust spot and jamming up, look in the plug holes with a flash lite, if all rusty well junker, my guess is that the crank is more than likely junk, but if the cylinders look good pull the v/c and check as suggested by others but also pull the pan and check the insde of the bottom end DONT spend any money till you know that its got, good luck you will need it.
 
With the bike sitting outside for a year without plugs, carbs or exhaust and the engine half full of water, I think its pretty safe to say its a goner.
There will be too much internal rust damage to consider tearing down and repairing. Its far cheaper and easier to buy another engine on ebay.

Earl

pasteurized said:
The carbs, exhaust, and plugs are out of the motor (and carbs and exhaust have been off for roughly a year, as it has been sitting outside in the weather, that sort of bugs me). Emptied the oil to move the bike and it was half oil, half water.
Click to expand...
 
Thanks for the input guys. Will see what happens tomorrow, but to be honest this would be a great opportunity to tear the engine down and get a hands on of some of the internals.
 
engine

engine

Thats the right attitude, you can learn a bunch from a tear down
 
Just an update, nothing changed overnight. I think a rebuild is in order, or at least a teardown and see what exactly happened.

Thanks for the input, all.
 
Heh yea I will, but it may take a little time before I get to it.
 
Sounds like you have nothing to lose by stripping it down. Few tips. tho. Get ahold of a manual. Have a good 4x6 area set up and as you disassemble, try to lay it all out in order. Replace nuts, bolts, washers back into their threaded areas as soon as possible. You are probably gonna get broken off bolts but don't fret too much. You can carefully drill out broken ones and insert helicoils from kits. I wouldn't say a stuck valve would stop the engine from turning. More like a crank or ring problems. And, as for the water; don't forget that the internals are deeply saturated with oil that might actually protect the parts from water. Then again... Good luck.
 
You must log in or register to reply here.
Back
Top