help with a mystery..

[sgoetz]

My GS650GL is having problems this year. When I brought it out of the basement this Spring it eventually fired up (usually takes awhile when cold) and idled ok, but it bogs out every time I give it gas, even just a little and even after warm / warmed up. It revs up when choked, but as soon as I give any throttle it just bogs / croaks outs. My thought is that its gas-starved, but I have tried the following, in approximate order, to no avail: (1) draining & changing the gas, (2) cleaning the tank petcock (it was clean), (3) taking off the gas cap (to ensure air flow / check for vaccuum problem in tank), (4) making sure the air cleaner and box were clear or obstructions (they are), (5) using an unlit propane torch to check for vaccuum leaks around hoses, carb boots, etc (as well as visual inspections), (6) opening the carb drain plugs and tank valve (gas flowed normally from each carb, so no stuck needle-valve), (7) adding carb cleaner to the tank and running (to extent I could using choke), (8) finally, taking off the carbs and checking for any obvious problems / issues, cleaning them with carb cleaner spray, making sure the airbox was clean & clear. Put it back together and, ugh, same problem. I will do compression tests but doubt that's it. It seems to 'run' fairly smoothly, not backfiring or missing, but will take no throttle. I am perplexed and looking for thoughts on what I might be missing - has anyone encountered this? Thanks for any help / thoughts. Scott

[snowbeard]

maybe the jets are gummed up from sitting. Did you use stabil in the tank? maybe try some seafoam in the tank and run it/let it sit?

or pull the carbs and just clean what you can reach with the float bowls off?

just a few thoughts, unfortunately nothing definitive.

[Nessism]

maybe the jets are gummed up from sitting. Did you use stabil in the tank? maybe try some seafoam in the tank and run it/let it sit?

or pull the carbs and just clean what you can reach with the float bowls off?

just a few thoughts, unfortunately nothing definitive.

When the bike sits the gas turns to varnish which plugs internal jets – particularly the pilot jets. Rubber o-rings inside the carbs, and on the rubber carb runner boots, get hard and do not seal properly. Only proper fix is to fully strip down the carbs and dip them in carb cleaner over night. Once clean, assemble the carbs with new soft parts.

Some people get away with not doing this…at first. But it’s a pay me now or pay me later situation. I suggest just getting on with the proper fix and don’t waste energy trying to shortcut the process.

[KEITH KRAUSE]

Most likely cause is the carb components have varnished up.
While cleaning, be sure the diaphragms are all in good condition. A torn diaphragm will allow an idle all day but accept no throttle.
Keep carb cleaner away from all rubber parts.

[TheCafeKid]

Im with them...im working on the same problem right now on an xs400 yammie... i had pulled the carbs apart and dipped what could be dipped. didnt notice any tears in diaphram but that could be it. Im more inclined to think its the pilot circuit (tiny tiny holes really hard to honestly get all the gunk out) My xs runs great on idle and choke, but as soon as you roll the throttle or take the choke off it dies. I have been told the pilot circuit deals with the first quarter of throttle roll on, so i am starting there, and maybe thats your problem or at least part of it too..

[BassCliff]

Hey howdy hey!

Mr. sgoetz,

I noticed that that was your first post. Let it be known that on this day you are hereby cordially and formally welcomed to the GSR Forum as a Junior Member in good standing with all the rights and privileges thereof. Please note that "good standing" implies pictures! :-D

Yes, I concur. The Carburetor Cleanup Series may be in your future. Clean all the little nooks and crannies. O-rings and carb boots may be in order.

Thank you for your indulgence,

BassCliff
(The unofficial GSR greeter)