GS 450 only running on one cylinder

[Bigmoe]

Hi all I am new to this forum. I picked up a 1983 Gs 450 this last fall and have been working on it this winter, the bike has sat for 12 years without running only has 4400 miles on it and it was stored under good conditions. I first drained the the tank of old gas and pulled the carbs off for a tear down and cleaning. all looked good put it back together and only will run on left cylinder.I verified that it is not a spark problem and did a compression test all good, I have taken the carb apart again and verified all passages are clear and clean and again checked the float level measurement have also replaced the O rings at the intake  boot to the head, put all back together and stuck them on the bike and still only 1 cylinder. Oh and I did also remove the welch plugs so as to adjust the jets.

Not sure what I am missing. Thanks in advance for any help you can give.

[bluedog59]

Is the r/h carb getting fuel ? Welcome to OSS btw.

[jensvonbustenskjold]

Welcome to OSS!

Since you are new, the thing you are missing are turbo!

Are the plugs vet from gasoline, fuel is actual entering the chamber?

How did you check sparks? Could be pretty OK on top of the head but not strong enough for a running engine.

How about the cdi/ignition unit? After a decade of stands still old electronic as capacitators dries out. Could give you a hard time.

 

We like photos, just a friendly advise.

[Bigmoe]

Well the bowl is filling for sure. And yes I only tested the spark with the plug grounded on the engine it looked fairly strong to me but I was wondering about that as a cause. Is there another way to check? I have actually ridden it a few miles on one lung. Thought I might see unburned fuel at the exhaust? Did not see any. The plug also looks new just like it did when I put it in and really does not look wet. So then will that CDI unit run one cylinder but not the other? And is there a way to test it?

[Mike711]

If the plug is dry after driving it then it's not getting fuel. Strip the carbs again.

[jensvonbustenskjold]

Sparks getting wet with only light cranking if it gets sufficiently fuel. Looks like a fuel problem, which is good, a lot better than ignition. 

In addition I would consider new intake boots. 

[Bigmoe]

You know I tried to find new boots, and the closest I could come was new o Rings. Do you know a source? I also thought I might try unhooking the other plug wire and putting some gas in the non functioning cylinder and seeing if I get any explosion.  Just to try to rule out a spark issue. Does that sound reasonable?

[jensvonbustenskjold]

Parts 

 

Select model 

https://www.cmsnl.com/suzuki-gs450_model13427/

 

Boots under head

https://www.cmsnl.com/suzuki-gs450e-1983-d-usa-e03_model16014/partslist/BLCK0013.html#.YmAqO_c8zDs

[bluedog59]

A little bit of fuel down the plug hole to see if you can get a cough and a bang out of it is a handy way of finding the problem. Only use a very small amount, you only need it to fire, not run to the end of the street. I'm not sure the inlet rubbers are the source of the issue, they would let excess air in but wouldn't stop fuel flowing enough to wet the plug. Having said that, a new pair would be a good idea as the originals will be well past their best.

[Captain Chaos]

I once had a similar problem (on a GS500), I mounted the left carb on the right cilinder and the right carb hanging in the air. It fired up on the right cilinder only. This ruled out ignition/compression issues so I knew the carb was the problem.

 

[Bigmoe]

Thanks for the sources for the boots, and all the ideas, had no problem finding boots for the 82  GS550 that I also bought from the same guy. But had no luck at all for the 450. I tore the carbs off again (I'm getting pretty fast at it.)  Started right off pulling the main jet and that made me start to feel really stupid, as it was plugged with I know not what, but plugged it was. I was so sure that it was open that I did not even look at it yesterday. Well long story short, that was the problem. But its not the end of the story probably as it is running fairly rough rode it a few miles and it would be a little boggy then all of the sudden take off like a shot. So I will probably be looking for more help. Thanks everyone.