GS650 idles but dies with throttle

[Steve]

Anyone have any suggestions for other next steps or things I can test?

Just for fun and games, turn your mixture screws out to 3 turns.

Also, try turning the throttle just a little bit slower.

These carbs do not have accelerator pumps. The vacuum-operated slide does a fine job in a stock situation, but your airbox and filter is not stock, so you need a bit of extra gas. Until you get everything else resolved, the extra turn on the mixture screws might be enough. It's certainly easy and cheap enough to try and just as easily and cheaply reversible.

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[powderhound]

Alright, after a couple of weeks of tinkering, the bike still isn't running right. It idles fine at about 1100rpm, and it revs up with throttle (but still dies with throttle quickly applied). However, when it's in gear, the engine dies as soon as any load is put on it. Even slowly accelerating up a small hill (out of the garage) is enough to do it in.

I've now got the stock airbox and a UNI factory replacement filter, and as far as I can tell, everything is pretty well sealed up.

I was hoping to take the bike around the block to see if I could get some more info about how the engine responds under load, 1/4 throttle, 1/2 throttle, etc, but I could barely get out of the driveway, let alone take it for a test drive. I'm starting to think that I might not be getting full compression in the cylinders. Anyone have any advice for tackling this one?

 

[tom203]

check that your mechanical advancer is free to move. Do your vacuum diaphragms look good with tabs in correct spot?

 

[BigD_83]

I'm starting to think that I might not be getting full compression in the cylinders. Anyone have any advice for tackling this one?

Have you had a chance to test the compression since you got the bike?

 

[roeme]

powderhound, what kind of instrument buckets are you using? I'm searching for something like that for months now!

(oh and anybody else who knows.)

 

[Guest]

That sounds like it's really lean. Are you sure the jets are meant for the 650? And float heights are correct?

 

[powderhound]

roeme: They're actually the stock gauges, with the center electronics removed. It was actually really easy to remove once the gauges were off the bike.

Chancho196: The float heights were correct, but I hadn't verified the jets. It turns out that the bike was having a compression issue. Unfortunately I just didn't have the time / resources to do an engine rebuild, so it's off to a new owner. I'm hoping to save for the winter and then get back into the GS game next summer.