550 poor start and idle after bottom end rebuild

[Guest]

Hey guys,

So I've started a couple of threads in regards to my 1980 GS550. The short of it is that I spent too much money on it only to discover that it ran beautifully except for in 2nd gear, where it would lurch like an idiot when I applied and power at all.


This: http://www.thegsresources.com/_forum...d.php?t=206259
This: http://www.thegsresources.com/_forum...d.php?t=208385


-So I swapped the transmission.
-I also cleaned the carbs according to the tutorials on BikeCliff's website (I skipped the carb dip, only because the bike was running very reliably except for the transmission problem before the rebuild)
-Bought the O-ring kit and replaced all the o-rings from Robert Barr.
-Replace Intake O-ring as well.
-My airbox boots were kind of wobbling around in their sockets, so I wrapped them with some thick and meaty rubber bands around the diameter where the boots make contact with the sockets, it seems to be in there nice and tight now.
-The PO seems to have already applied weather stripping to the airbox cover
-Replaced exhaust gaskets
-Replaced all spark plugs with proper gap (.030)
-Did not check the valves yet, but I will. But again, the bike was running very well before the rebuild so I thought I could just leave these alone (I've been reading enough threads that i know I'm going to catch grief for this)

So the bike won't start and maintain an idle now unless i spray starter fluid into the airbox (which I don't like doing)

The plugs have spark, but they're not getting wet. So I'm not getting gas. But the bowls do have gas in them, so can I rule out the petcock if the bowls are full? My petcock only has two settings, On and Reserve, and neither seem to make a difference. It seems that when I suck on the vacuum line I can get it to start for a bit its still not getting gas consistently.

I hope that's enough info. I'm wondering if it could still be the valves if the bike was running very well before. I did rotate the engine once or twice when the bottom end was disassembled so I'm wondering if that would screw up the timing... I sure hope not.

Thanks guys.
I'm in Los Angeles by the way if anyone has a free weekend to help a brother out... I would supply all the beer you need to make a quality diagnosis.

[Agemax]

have you got the vacuum pipe connected to the right port on the carbs?
before you go any further you should check the valve timing and clearances, and the ignition timing

[egetron]

yes, it's connected to the number 2 carb.

I plan on checking valve timing as well as ignition timing very soon.

Dry plugs makes me think this girl is not getting gas.

[Sci85]

You can rule out the petcock if the bowls are full. Having gas in them is NOT the same as having a proper float level. There's a procedure for checking that with clear tubing attached to the float bowls. I believe it's on Cliffs site. Check that. You also need to check the valves as that is a cause of hard starting.

Anytime you rebuild the carbs you should always dip them. It doesn't take but the tiniest dirt to block a pilot circuit or choke circuit. If the plugs are truly dry after cranking sufficiently long on choke, then pull the carbs and go back and dip them properly and clean all the little passages, poking them clean with piano wire and blowing them out with compressed air. Make sure the float height is set correctly and the actually float. Follow the rebuild guide to a T and you won't have any problems.

Good luck.

[cowboyup3371]

How long did the carbs sit while you were replacing the orings? It's possible it's gummed up inside; are you getting fuel into the bowls?

[egetron]

I should say that even though I didn't dip, I did thoroughly spray and poke all passages that were mentioned in both of the CV rebuild tutorials on BikeCliff's website. Also, the carbs looked really clean when I first disassembled them and the bike was running great before I disassembled. I've read a million threads where there is a back-and-forth between a stubborn newbie and a bunch of seasoned posters about whether or not the carbs were thoroughly cleaned, so I will clean them again and do the full dip, I just want to try some other stuff first.

When I re-assembled them, I didn't mess with the float heights, but I'm wondering if maybe that's it. for my own edification... how does float height affect performance? what function does float height play beyond not letting the carb bowls overflow? If the bowls have gas in them, would float height be a factor in the cylinders not getting gas?

[Sci85]

Yes,it certainly can and could affect the flow of gas. If the float level is too low, no gas will be drawn through the passages. Too high and it will run too rich, possibly overflowing and leaking. So yeah,it affects things a lot.

[egetron]

ok, so I didn't know that my petcock had a Prime function. (the lever only has two settings: ON and RES) but It turns out if you turn that little flathead screw on there, it bypasses that, and boom, she started right up. I would even say she runs well! Solid consistent idle, took her for a mini spin. Seems to have power in all the right places. No bogging. Feels pretty good.

This means that I need to rebuild or replace my petcock, right?
Any recommendations? I saw some shiny/sexy aftermarket ones in some of these build threads, but those look expensive... what other model years will work on my tank and have a lever with a prime setting?

Right now, only problem appears to be that the 1st carb is leaking gas from where the bowl seals. I did notice that my number 1 pipe is not as hot as the others. Still hot, but definitely not as quick to burn my skin off. I wonder if that's related to the gas leaking from the 1st carb? Anyway, I have new gaskets on the way.

And yes, I'm still going to check my valve clearances.
How do I go about checking ignition timing on this bike? I can't tell if I have electronic ignition or points... it's a 1980 GS550E

-Ege

[Sci85]

Good to hear.

Take the ignition cover off and have a look. It's on the right hand side, under the Suzuki emblem if you still have yours. If you can't immediately tell the diff between points and electronic ignition, well lets just say we have bigger issues...

[egetron]

Such biting wit!

mine looks like this:


Can I adjust the timing on this?

[Sci85]

You can adjust the timing on points or electronic. You have electronic.

[egetron]

thanks for the help !

[duaneage]

You shouldn't adjust the timing any more than correct. Line up the F with the fixed mark using a light. You a can also static time to the T with the piston at TDC