Surging Idle?

[ZukiJc]

Hello all, I have a idle issue as the title states. I have been serching the forums all morning and have not found a solution yet...

I recently bought a 85 gs 550l, and I got it running no problem (ran great, PO parked it for about 2 years, then I bought it). Once you get it started (takes a min or so playing with the choke) it runs enough to play around on the driveway to test it out. Problem is, if you dont' manually keep it reved up, it will stall out on you. I have already adjusted the idle set screw between the carbs, I have also adjusted the cable ends. I can't seem to get it to where it wants to idle.

Sometimes it will also just rev up to about 4 or 5k on its own and will just sit there and eventually back itself down (normally only when its warmed up).. it will proceed to idle down until it stalls itself out unless I am on the bike and playing with the throttle manually to keep it running, but then it will tach up again...

I am looking to find somewhere that sells plugs for it (they are black, but not too bad, and it seems to have good spark as well) and I am also looking for a new air filter for it (my old one is nasty looking and the foam looks like its fallen apart)

Any suggestions on other things I can try in the mean time, and would a filter or plugs really affect the idle like that? Like I said it runs strong, just won't idle and does that random surging deal after it warms up.

Thanks in advance everyone, and I appologise if there is already a thread with this solution as I searched and didn't find it...

James

 

[RacingJake]

That's a lean condition, carbs may need to be cleaned out, lack of fuel to carbs (petcock problem) or floats sticking closed. Or boots are cracked allowing air to be sucked in.

 

[ZukiJc]

Lean huh? Ok, I will try testing the seals of the carb with the WD40 that I read in another post here to see if its sucked in.. I am working on getting the plugs and filter as soon as I can find somewhere that actually has them for a 550.

Then I will check the petcock (although its running "fine", so I assumed that it was getting fuel, is there a good way to check the petcock? becuase I know there is some flow of fuel)

Then I will check the floats and see how they are looking and clean up the carbs somemore.

Thanks for the responce, I am racking my brain on what to try before giving in and just taking it to a shop somewhere.

 

[ChuckB]

Above mentioned things should be checked but I would also go to Wally World and get a can of Chemtool B-12 and put it in your gas tank, 1 oz per gallon. I did this and saved myself the aggravation of taking my carbs off and cleaning them This stuff is simply amazing.....Good Luck

 

[skip]

after you clean the carbs really good and find all vacum leaks, sync your carbs. If they are really out of sync they will idle high and then drop back down really slowly and sometime visa versa. they will idle low and slowly climb.

 

[Jared]

Yes Hanging rpm's is a sign of a lean condition.
Bike sat for 2 years but ran fine before parked...

Is the gas fresh...?

Check all the stuff mentioned already -- it really sounds like you need to do a good carb cleaning... Specifically the pilot jets -fuel evaporates out of the bowls and all the additives and whatnot in the gas get left behind and clog up the small openings in the carb.
I've worked on a number of different bikes...and have dealt with getting long term stored bikes running again...Most of the time it's the pilot jets being clogged. They are pretty much what the bike runs on at idle and since they are so small they are the most likely to get clogged.

Some people swear by yamaha's Carb cleaner....you mix it with gas... fill the bowls with the mix ( Carbs stay on the bike )... slosh it around and let it sit an hour....drain the stuff back out of the bowls and fill the bowls with fresh gas... and give it a try... You don't try to run it on the cleaner. If it doesn't work repeat the process but leave it in longer...

I've never used it personally.....but a friend of mine does and likes it. I'd just rather see them clean with my own eyes.... Anyway..

Good luck.