GS650E hesitation when hot

[Guest]

Thanks in advance for any much needed help!
I've been having an issue with my 81 gs650e after riding for an hour or so. When I stop at an intersection the bike falls on it's face when I begin to accelerate, but no hesitation at all once I'm above 4k or so. I'm not sure if it is a carb issue or possible ignition problem. Bike is all stock and carbs were rebuild last fall and thoroughly cleaned. Bike runs perfect otherwise.

[tom203]

Takes an hour to have this issue? Strange, check that the ignition advance moves freely to rule it out. More likely carb issue though.
When you rebulid carbs, did you put those rubber plugs back in over pilot jet?

[Leonard]

I did replace all the rubber plugs when I rebuilt the carbs. I've put a few thousand miles on in between long trips without a problem, but then again I only notice it if I'm stopping at lights. Next ride I'm going to bring my multimeter and check the coils when it acts up before I dig back into the carbs. I'd rather do without all the swearing. I'll give the advance a check as well. Thanks

[tkent02]

How did you adjust the mixture screws?
Did you change any of the jets?
Have you checked the fuel level in the float bowls?

[Leonard]

Did not change any jets. Bench tested float level and seemed ok. Not sure where I'm at with the mixture screws

[chuck hahn]

Ride it and as it acts up easily add some choke. If the problem goes away and you feel it get more power then your running lean. If it doesnt change..or bogs even more..youre running too rich.

[chuck hahn]

Ride it and as it acts up easily add some choke. If the problem goes away and you feel it get more power then your running lean. If it doesnt change..or bogs even more..youre running too rich.

2 to 2 1/2 from gently seated on the screws is the basic starting point.

[Leonard]

I'll try checking with the choke when I ride home tonight. Thanks

[chuck hahn]

If nothing solves the problem then be sure the diaprams are seated properly in the grooves so there are no ppinches that may cause a vacuum leak. No need to pull the rack, just take the covers off and recheck they are installed right in the grooves.

I have seen some that were seated right but squished to the point the rubber wasnt pliable and still leaked causing problems. A little smear of RTV resealed them and the bike ran like new again. Just another thing to consider down the road.

[tkent02]

How do you bench check a fuel level? the carburetors need to be on the engine and the engine running to check the fuel level.

But...

If you don't know where your mixture screws are set, start there. Do you know the proper procedure for setting them?

[Leonard]

Not sure as to how you can check float levels on the bike running as there isn't much room. I used clear fuel line attached to a hose barb on the float bowl to check the leels as well as physically measuring float height at the needle valve. I adjusted everything to spec, but I can check and see where exactly I'm at.

Chuck, I will pull the covers off and check the diaphragms, glad I replaced all Phillips screws with socket head screws, best investment so far.

[chuck hahn]

Im not saying your diaphrams are in wrong...all Im saying is the rubber gets squished and over time takes a "set" and wont make a good seal between the carb body and the covers. Just the slightest little smear of RTV seals the gaps and the vacuum is restored so the diaphrams work and respond as they should. Not a perfect world solution like replacing the diaphrams but it works.

[Leonard]

This bike is full of not perfect world solutions so I wouldn't be too afraid of some rtv. I'll put in a ride tonight and see what happens. Thanks for your suggestions, gives me somewhere to start now.

[Nessism]

How long since the last valve adjustment?

[tom203]

Your first post said. "but no hesitation at all once I'm above 4k or so. " diaphragms must be sorta ok, but check them anyways. They are real fragile , so be careful. Though it's hard to check them without removing them entirely and holding up to light .