Diaphram question

[jonn1963]

Took my 1980 gs850 G to the bike shop for a carb cleaning and sync, and to have the valves adjusted. I've put around 9000 miles on it since getting it with no problems but it allways seemed low on power and would only get around 33 mpg. Picked the bike up and seems to run much better. The problem is the rpms dont drop down. If I shift at 2000 the bike stays at 2000. The idle does drop slowly or I can force it down by downshifting. At a red light the idle will increase and I have to release the clutch to bring it back down. Took it back and he pulled two diaphrams and said I need to replace all four. Does that sound right. They are awfully expensive and would hate to spend that and it not cure the problem.

[Mith]

Sounds like you have an air leak. Have you replaced the O-Rings that are between the carb boots and the head?

[hikermikem]

Sounds like air leaks. Perhaps when the shop removed your carbs for cleaning they didn't do a good job sealing all the places that could leak air...

I'm not sure cracked or holed diaphrams would result in a hanging idle, most likely the bike wouldn't accelerate with bad diaphrams.

Check all the clamps from the boots to the carbs and make sure they're tight.

Oh yeah, and don't ever bring it to a shop - do the work yourself. Plenty of info & help here to make sure you get it done right.

Good luck,

mike

[Nessism]

You need a new mechanic. Or better yet, learn to wrench yourself. Your bike is 29 years old and paying someone to keep up the maintenance will quickly add up to more than the bike is worth.

Regarding the hanging idle, that is a classic example of a lean carb mixture. Did this mechanic of yours replace the intake boot O-rings? Where are the pilot mixture screws set (they should be about 2.5 turns from lightly seated and then adjusted for the highest idle speed after that)?

Sorry to sound turse but honesltly now, the bike is old and most machanics don't know how to work on these bikes. There are countless stories about GS owners getting hosed. Also, if you would just the search function you would turn up MANY threads on bikes with a hanging idle - this is the number one problem on old GS bikes with poor maintenance.

[jonn1963]

The mechanic is an old school guy who's been working in the area for 40 yrs but I think maybe he missed something being in a rush. I think maybe I'll buy an extra set of carbs and a rebuild kit and do them myself. At least he only charged me $100 including the valve adjustment.

[Nessism]

Before you go though the trouble with the carbs, make sure these seals are fresh.

[rustybronco]

I think maybe I'll buy an extra set of carbs and a rebuilkit and do them myself. At least he only charged me $100 including the valve adjustment.

Rebuild kit?
you dooon need no steeeeeenking reeebild keet....

http://www.thegsresources.com/gs_carbrebuild.htm

http://cycleorings.com/

just a hint... the carbs you have, are already paid for.