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Please help ASAP guys

  • Thread starter Thread starter Corvetteman115
  • Start date Start date
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Corvetteman115

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Hey guys this is my first post I've had many GS bikes and I'm an ex suzuki tech and I'm completely stumped.ill make this as short as possible! I have a 1982 gs550l that I cut the mufflers off of and installed baffles I also removed factory airbox and put on homemade foam pods. I went from a 40 to a 44 pilot jet and from a 92.5 to a 127.5 main. Started bike ran and idled great all the way through the power band, got on it and drove it about a mile all the sudden it started falling on it's face at 4k rpm and bogging down running on 3 cylinders (no smoke no backfiring) I limped home to find all the plugs black and fouled. I assumed i over jetted it, I jumped down to a 115 main and changed plugs to one degree hotter, same problem. I then went back to stock mains and it's still fouling plugs and still falling on it's face now at 5k rpm, just no power at all above that point and bogging and again running only on cylinders 123. Yet if the bike Is idling it will run great and run all the way to redline on all 4 cylinders with no problems AT ALL. I'm stumped why is my bike falling on it's face at 4k and why does it keep fouling plugs?! All cylinders are getting spark, bike has good compression. Is it possible the stock mains are too rich?!
 
Corvetteman115 said:
I'm stumped why is my bike falling on it's face at 4k and why does it keep fouling plugs?! All cylinders are getting spark, bike has good compression. Is it possible the stock mains are too rich?
Click to expand...

You answered your own question in your post. I highlighted the answer below...

Hey guys this is my first post I've had many GS bikes and I'm an ex suzuki tech and I'm completely stumped.ill make this as short as possible! I have a 1982 gs550l that I cut the mufflers off of and installed baffles I also removed factory airbox and put on homemade foam pods.
Click to expand...
It will always run like ass with "homemade pods".
 
I put the stock air box on problem slighty better but still breaks up at 4k underload after checking with a timing light the timing is off (advanced) is there a way to adjust electronic ignition? Or should I pull valve cover and check cam position?
 
Doesn't the 82 have a electronic advancer, none mechanical. Ignition timing is factory set and none adjustable unless it has an after market ignition. Your problem is your exhaust and air intake system. You also need to install your stock pilot jet,as unless you made major changes inside the motor you shouldn't have to change it. Also what has been the maintenance on this bike? Carbs stripped and dipped with new o-rings and floats set correctly? When was the last valve adjustment? If you are truely a EX Suzuki tech this should all be basic knowledge. Sorry
 
copy that^... are the carbs properly cleaned and rebuilt? we're not kidding when we say ya gotta do that.
 
Carbs were cleaned and rebuilt correctly floats are adjusted I find it very hard to believe that going up 2 sizes on pilot jet would have this effect in mid range power, pilots are for idle and low end, my low end is fine, bike does have electronic ignition however after removing cover and checking the air gap is severely off center as well as the nut being only hand right, after checking timing with light the timing is too far advanced tomorrow I'm going to pull the valve cover and check the cam posisition I have a feeling it's going to be a tooth off. As for being a suzuki tech I am however I went to MMI in the mid 2000s marjority of the bikes I've worked on have computers lol. I have had a few Gs's before but never had this problem with any of them, I don't know the history of the bike as it has been sitting for a few years and wasn't running when I got it
 
I thought maybe your Suzuki training might have happened after the heyday of carburetors had passed. Welcome to the forum.

Generally it doesn't take any pilot jet increase to tune one of these GSes for pipes and pods, I have tried one size up a couple times when I hadn't figured out what was going on yet, but when all was said and done took them out again.

Like you said, the pilot jets only control fuel in the smallest throttle openings, at these small openings there isn't any increased airflow over the stock intake anyway, in fact with a 4-1 pipe there is usually less airflow at the tiny throttle openings.
 
Hello CorvetteMan and welcome. I have an 82 550 as well. They have electronic ignitions but still run mechanical advance as you can quickly tell after you pulled the cover. They can be advanced and retarded just like any other non-computerized unit. Just loosen the screws holding the timing plate and have at it. Make sure and mark the current position first.

I just went through a rebuild of my engine and I run K&N open twin filters and a 4:1 pipe (but with a straight through baffle). Anyway, I thought I would need to go much richer as well and had the exact same problem you described. The bike just refused to make any power above 6K. I used a richer needle and main. I ended up going back to stock needle and one size larger main. Bingo! She rain sweet as could be after that.

Oh, and I also played with the pilot jet. I ended up going back to stock there as well.

I would go back to all stock jets and then increase one step at a time on the main until it runs best.

Good luck.
 
Sci85 said:
Oh, and I also played with the pilot jet. I ended up going back to stock there as well.

I would go back to all stock jets and then increase one step at a time on the main until it runs best.

Good luck.
Click to expand...

You usually do have to raise the jet needle, sometimes pretty far. I'm at 1 1/2 clip postitions now on my 550, looks like it may take a bit more. Mine has diferent carburetors, but the principle is a little bit similar.
 
Thanks guys I will let you know how I make out tomorrow after timing I REALLY don't feel like pulling these carbs AGAIN lol but if adjusting timing doesn't work I may have to, I'm already back to stock mains, I started at 92.5 when I got the bike then jumped to 127.5 then I droped it down to 115 (stock mains out of an 850 I had) then now I'm back to the 92.5 mains. I'll keep u guys updated an thanks for the fast help. I'm one of the few 27 year olds who likes these old bikes more then the new gsxr's lol
 
Your carbs may allow it tkent but my '82 had non-adjustable needles. I went to an adjustable needle with the 650 dynojet kit and tried in vain to get it to work fiddling with all different needle settings but it just did not want to run as clean with the dynojet needle, even leaned out. I'm a little lean now back on the stock needle but it runs super crisp so I am very hesitant to mess with it anymore.

I'll bet that if he goes way back down on that main it will run right as rain.
 
I'm back at stock mains and it still falling on it's face at 4-5k every time without fail. Revs in neutral all through redline and launches fine till u get on it and go then when u hit 4-5 there's nothing at all, it almost throws you forward with how quickly the power curve drops. There was no change in this with any of the mains from stock to 127.5 that combined with the timing being too advanced leads me to believe it is timing, my dad had a gs750 a few years ago and it was doin the same thing sure enough the timing was off a tooth at the cam (and topend had just been rebuilt by a kawasaki dealer that he got the bike from) anyway I will keep u guys updated after I adjust timing
 
Sorry to burst the bubble of the re-hashed/ misguided information that seems to abound around here but, the pilot jet actually has an effect on the fuel system through MOST of the rpm range.
Of course, it diminishes as more air flow enters the carburetor bores but it still is supplying fuel. This chart is for a 28mm slide carb in a 1000 cc engine...

 
Sci85 said:
Your carbs may allow it tkent but my '82 had non-adjustable needles.
Click to expand...

Non adjustable needles can be adjusted just fine, you just have to think about it a little bit more. Stacking washers, making your own clip grooves and buying a jet kit with good needles are all well within the abilities of the average GS owner.
 
HMMMM...lot of questions for having owned "many" GSs and being a "tech". Seems everyone knows better than the factory engineers and INSIST on hacking the pipes and using their brand of "home made" pods.....then come on and beg for help...hillarious.
 
Actually "chuck" I'm back at the stock air box. And if every one listened to what the engineers said then no one would do any mods ever, have fun with boring factory stock stuff if that's what your into, furthermore I came on here seeking 2nd opinions from old timers who have more experience with these bikes then me, my bad for asking for opinions? I'll get the bike running right chuckie. As for everyone else thanks for your opinions there much appreciated
 
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