Bike has strange lurching and low on power, please help troubleshoot

[Neon01]

I'll try to give all the details: its a 93 GS500E and it was in tip top condition (just a bit over 4k miles) before this happened.  I left the bike without riding it for about 3 weeks.  When I get back on it it doesn't want to start right away.  After a trickle charge on the battery (its only 1 year old) it starts right up.  I let it warm up for 5 minutes and start to ride.  The bike doesn't respond to throttle very well, as in when I increase the thottle past about 1/8th, it'll stutter and lurch.  Then if I back off a bit, it seems to like that and it'll surge forward.  It's also VERY low on power, and the problem seems worse in higher gears and on hills. 

I've pulled the plugs and they are fine.  It really feels like one of my cylinders just isn't firing most of the time, then when I back off a bit (or give a lot of throttle) the bad one will kind of "kick in" and I'll shoot off.  Could this be a carb issue? 

Should I try seafoam (do people seafoam bikes)?

Thanks, I'd like to ride one more time before putting her away for the year. 

[tussey]

I'll try to give all the details: its a 93 GS500E and it was in tip top condition (just a bit over 4k miles) before this happened.  I left the bike without riding it for about 3 weeks.  When I get back on it it doesn't want to start right away.  After a trickle charge on the battery (its only 1 year old) it starts right up.  I let it warm up for 5 minutes and start to ride.  The bike doesn't respond to throttle very well, as in when I increase the thottle past about 1/8th, it'll stutter and lurch.  Then if I back off a bit, it seems to like that and it'll surge forward.  It's also VERY low on power, and the problem seems worse in higher gears and on hills. 

I've pulled the plugs and they are fine.  It really feels like one of my cylinders just isn't firing most of the time, then when I back off a bit (or give a lot of throttle) the bad one will kind of "kick in" and I'll shoot off.  Could this be a carb issue? 

Should I try seafoam (do people seafoam bikes)?

Thanks, I'd like to ride one more time before putting her away for the year. 

my bike was doing this and the float height level was off. Make sure your floats are correctly set using the clear tube method.

[scratch]

I'm guessing that even in just those 3 weeks, the jets gummed up.  Otherwise, check for a strong spark from both spark plugs.  Pull one plug, ground the threads to the head (fins), and push the start button.

[Neon01]

I'm guessing that even in just those 3 weeks, the jets gummed up.  Otherwise, check for a strong spark from both spark plugs.  Pull one plug, ground the threads to the head (fins), and push the start button.

Supposing it was gummed jets; how would I fix that?  Would I have to take out the carb and clean the whole thing?  Or is there some chemical I can run through it to clear it out?  I've actually tried a small amount of the STP carb cleaner fluid that they sell for cars in the gas tank because I suspected it was my carbs too.  This didn't do anything.   

[scratch]

Fuel injector cleaner might be better.  Carb cleaner isn't good for rubber.  Or, find something that will clean the carbs that can be mixed and burned with the gas.  Otherwise, yes, you will need to bite the bullet and remove the carbs and clean 'em.

Make sure the spark plugs are seated.

4k miles on the clock means it might be a good time to check those valve clearances, too.

[NiceGuysFinishLast]

SEAFOAM!

[makenzie71]

seafoam is a horrible substance...

Use some Barryman's EFI cleaner, or pour in a can of B12 Chemtool...don't get your hopes up, though.  Fuel is one of the best cleaners out there.  You'll most likely have to pull the carburetors and clean the passages out, but it's not hard.  Pulling the carbs is straight foward and all you'll have to do is take one float bowl off, blow the jet passges out with air or using a long, stiff, nylon bristle, and then put that bowl back together.  Repeat with the other.

[94suzuki500]

SEAFOAM it, not cause it will help but the smoke looks really neato!! no but really it might help.  But then again, taking the carbs off is not that hard and youll know that they are clean and it just feels good to do work on the bike.  Carbs are easy, just dont force anything and youll be good.

[MarkusN]

Dunno why, but my gut says electrical. The ignition system draws quite a bit of current, and if the electrical system can not keep up with the demand ignition starts to behave all whacky.

[Jarrett]

seafoam is a horrible substance...

Why do you think Seafoam is bad?

[Jeff P]

This is not unlike my own recent experience.  I've been unable to do much riding in the past two months ( I know, I know), but each time after sitting for 3-4 weeks I have similar symptoms.  It's been mostly cured by getting some fresh gas in the tank.  I hadn't been using Sta-bil since I wasn't planning on having the bike sit for months, but for some reason or another it looks like I need it. 

Drain your tank and carbs and fill 'er up with fresh fuel.  Get some fuel system cleaner - Chevron Techron Concentrate is a good one.  The small bottle.  Use half of it in two consecutive fill ups.  Then on the next tank use Sta-bil and see how it goes.

jeff

[94suzuki500]

I had an electrical problem that made the bike lurch.  It was a plug that had come partially apart.  Possibly be your problem but it kinda sounds like the carbs though.