Wont start!

[Guest]

I just got a 1983 GS650g 88000kms, been sitting out in the elements for about a year or 2. I live in Vancouver BC so rainy cold weather here so its a little rusty. Ive cleaned out the carb throughouly, the tank looks really good no rust. Ive done a fair bit of reading and have the repair manual. Prior to this the bike was running in top shape. Ive changed the orings in the intake boots everything is sealed up tight except the cover for the airbox is missing. I replaced the spark plugs with new ones, no go....I read on this forum that i need to adjust the valves or else I could have little to no compression, Id really dont wanna do the rings, I really dont wanna do any rebuilding unless I have tooo!!

SO from all your experiences with this bike is this really an issue that could lead to little or no compression. The other thing that leads me to believe this is the plugs are totally dry no fuel and the carbs are CLEAN ultrasonic clean and every one of the plugs are dry no fuel ever reaches them.....ive got compression thats about 70-75 on each cylinder.

ANy ideas Im still waiting on the Suzuki valve tool so I cant hold down the valve until that to reshim it but ill check the clearances. Any other ideas ???

Thanks in advance.

[Steve]

I was going to question your carb "cleaning" until you mentioned ultrasonic. Did you replace all the o-rings in the carbs?

You don't really "need" the official valve tool to hold the valves. You can use a folded zip-tie through the spark plug hole.

Click the link for the tutorial, but here is basically how it works:


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[Slycox]

As someone who just did their valves for the first time and using the above method I recommend it. Those shims were a PITA to remove with 2 hands. Pretty simple once I grasped the concept

[tom203]

Since you said. "Prior to this the bike was running in top shape." Probably needs valves adjusted,but the dry spark plugs suggest no fuel is being delivered thru "choke" system. .When you actitivate choke lever, a bar joining all four carbs slides out - this enriches things to help cold start. If bike is cranking, but plugs are dry, something is amiss . Maybe the petcock is not delivering fuel - do you understand the "PR" position on petcock? Or maybe the ultrasonic failed to clean out "choke" passages. Fuel for enrichment system travels up little passages from fuel bowl to carb throat- these gum up easily

[Sci85]

70-75 lbs? That's very low compression. Are you sure you are taking the readings properly? If they are truly that low, then something is surely not right. And clean the carbs again. Make sure you can see down the jet passages (run a properly sized wire through the jets to get any junk dislodged). The starting and enriching circuit passages are TINY and it doesn't take much to clog them up.

[JTGS850GL]

Remember that you need to do the compression readings with the throttle wide open. Otherwise you'll get artificially low readings.

[Murphy Chow]

I will keep checking all great ideas, been really wet over here in Raincouver !! But I will dbl check my carb cleaning, Ive worked on tonnes of CB's and never ever had an issue like this. When I get a chance ill take the carbs off and squirt some carb cleaner into the intake to dbl check whether it fires. The compression tester I have may be faulty, I think my neighbour who borrowed it broke it because i was checking my lawn mower and i was getting 20 psi on a running mower. I can see he might of stepped on it or something, anyways that is a something else. I will get back to and let all you guys know. Everyone has been awesome helping me.

The carb was cleaned ultrasoniclly and everythign was replaced no leaks fuel reaches the carb, it was blown out with compressed air every passage that i could blow int was blown and flowing freely with air, jets were clear and see thru. Ill keep checking but for now Ill ride my Honda CB

Kind Regards from Raincouver!!!

[Sci85]

Are the carb float bowls full of fuel (open the drain screws with the petcock on prime and check that gas flows out)? You said the spark plugs are dry indicating no gas is getting into the cylinders. Well, that's pretty easy to diagnose. It's either the petcock, fuel line, or the carbs not flowing fuel. Check them all starting at the petcock. One of them has to be the culprit if you are sure the plugs are dry. Good luck.

[Murphy Chow]

It started up finally, but i think the petcock is toast. when I set it to prime fuel should flow out just because of gravity, there is no gas coming out

[habsdoc]

The prime function still needs a bump of suction to begin working. Just blip the starter when you have it on prime to make sure it really is not working.

[tom203]

The prime function still needs a bump of suction to begin working. Just blip the starter when you have it on prime to make sure it really is not working.

Nope, only the lever less 1980 petcock had this "feature" . In "PR" , spot fuel should flow nicely (if there is gas in tank) without any help.