My father-in-law bought a 07 GS500, with only 700 miles on it. Bike was in great shape, but clearly it has sat around most of its life. It runs only on choke, and on choke it runs around 3000 RPM. The second you take it off choke it dies. Obviously this means the bike isn't getting fuel through its idle circuit. Pulled the carbs cleaned the circuit to make sure it was clear, checked the diaphram for pinholes...all of that checks out, the carbs were whistle clean. I noticed after we put it all together the slides werent moving while the bike was running. So, we tried finding vacuum leaks by spraying wd-40 around....didn't find any. Then we completley capped off all vacuum ports on the bike, and ran it on an IV of gas. Slides still didnt move.....I am at a loss to figure out where else the vacuum leak may be. I am pretty sure it has to be a vacuum leak because I would assume the slides should be moving even if its running on choke. I was looking at the shop manual yesterday and I noticed that there are two holes in the slide that provide the vacuum source for the diaphragm. I am going to check those this weekend. Does anyone have any ideas where else I may look?
Also, we plan on disconnecting all of the Cali emissions stuff. I know I can remove the line that runs the the PAIR valve, but do the two nipples on top of the carbs at the diaphragms need a vacuum source or can they be capped off too? Not the big one with the filter, I know I need that one, but the little ones with ~1/8" line connected to them.
Thanks,
Dave
those are just capped on mine, just the one vac line from the left carb to the petcock is all i have
Awesome, thanks for the info. That will help me eliminate a lot of potential leaks!
Few possibilities...
Your slides may be jammed, thanks to old gelled gas. One of my slides was like that on the 93 GS I picked up.
Your vacuum diaphragms may be busted.
Vent line to the diaphrams may be plugged or capped (I leave mine open. From the factory, a vent line runs from the carbs to just behind the battery box.)
Thanks for the reply,
Slides move freely by hand and feel smooth so they arent stuck.
The diaphragms are good because when I had the carbs apart I checked them for pinholes...cracks and they are perfect
Ill pull off the factory filter that was attached to the vent line and see if thats the culprit.
Thanks!