85 gs 700 e low compression (90-100)

[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.
thanks

[blowerbike]

how does it run?

[85gs700]

i have not been able to get it started....

[Griffin]

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.

[blowerbike]

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...

[85gs700]

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.

[blowerbike]

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.

[85gs700]

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!

[blowerbike]

you should be running a "st.3 jet kit".
the needle's are the big deal..the shape and length.