• 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.

85 gs 700 e low compression (90-100)

  • Thread starter Thread starter 85gs700
  • Start date Start date
8

85gs700

Guest
so i did the old oil in the spark plug whole and the compression reading's where still at about 100. i was wondering if anyone knows how to check and see if the cams are in line with the timing marks and how to find top dead center on this model of machine. also what should my compression readings be i had a friend tell me they should be at around one fifty.:confused:
thanks
 
Since you can't start it, you're talking cold compression readings, which are going to be quite a bit lower than hot compression readings. That being said, are you cranking the engine with the throttle wide open?

Did the bike sit for quite a while? Could be stuck rings. Squirt some penetrating oil or marvel mystery oil in the spark plug holes and let it sit for a day or two. Rotate the engine by hand, you might get them to break loose if they're stuck.

Did you check valve clearances? Improper clearances can kill compression. If you don't know how to check and adjust them, the manual is here:

http://members.dslextreme.com/users/bikecliff/

You want to download the GS750E/ES '83 manual, and the '85 GS700 supplement.

Normal compression on that model is in the 140-160 psi range. My 700ES has over 70,000 miles on it. Last time I checked compression on it, I got readings around 125-135 psi. She still runs like a champ, so I don't worry about it.
 
Last edited:
i'm sure the engine is fine...
do the maintenance and complete carb job.
there's so much information needed such as how long sense last ran ect...
 
Yeah i had the throttle wide open. it has not ran in a while but i did put oil in the spark plug wholes. ill check the vales and get back to you thank you.
 
on a vacuum carb bike you just about have to remove the air box to get accurate readings from a compression test.
and yes throttle wide open and crank until you get the highest reading with all the plugs out and a super strong battery.
it does need to be hot/ran..numbers can vary 20-30 lbs more or less.
 
well i finely checked everything and the it passed the leak down test. the previous owner changed the air box out for pod filters. does anyone know what jets i should be running its seems lean!
 
You must log in or register to reply here.

Similar threads

P
GS1100L 4 valve rebuild vendors and thoughts on my investigation
Replies
7
Views
126
prichmon
P
KiwiAlfa156
Retarding Ignition Timing
2
Replies
25
Views
361
rphillips
R
timebombprod
Setting the timing properly
2 3
Replies
42
Views
599
timebombprod
timebombprod
Tashields21
New Coils, no spark at 1 and 4. Narrowed down to CDI (maybe?)
2
Replies
33
Views
510
gs scott
gs scott
martin_montreal
1978 GS750 Head, 4:1 exhaust, spoked wheel, some background & advice
Replies
6
Views
204
kochic
kochic
Back
Top