Hey guys, forum noobie here. Nice to see a great community for a great bike. 

So...I recently bought a 1994 Suzuki GS500E.

When I first bought my bike I was faced with a high idle issue. The choke cable was broken but I bought a new one and replaced it. That didn't fix the problem. It would hover around 4000rpm when it was warmed up so I would turn the idle screw on the carburetors down to let it idle normally, but even then if I revved it up it would drop back to normal rpm somewhat slowly. Otherwise it ran fine. I'm thinking this may or may not be due to a gummed up throttle cable, so I ordered one and am waiting for it to arrive in the mail.

By this point I had already put over 100 miles on the bike, so everything from here on was a new issue. I left my bike outside with an old cover on, which was worn and had some holes. It rained overnight and the bike wouldn't run the next morning, so I was under the assumption that some of the rain water got into the tank through the gas cap and made its way into the carbs. I purged the tank and carbs of fuel. When I put the carbs back on the bike and started it up, the bike had some other issues that I'd never experienced before. There was afterfire (the exhaust would pop loudly) when I'd get around 7000rpm, and the right exhaust pipe which emerged from the right exhaust manifold started to turn red hot. Also, the bike wouldn't go past 8000rpm even though the redline is around 11-12k. I had no problem getting it to redline before. So the carbs were taken off and fully disassembled and cleaned, and put back on. I turned it on once again and while it wasn't giving me nearly as much afterfire, the bike still wouldn't go past 8000rpm.

So far I've been advised to look at the wiring and the coils. I also changed the fuel lines and air filter. Can anyone please shed some light on what's going on? Thanks a lot!

Yea air filter may be getting wet, and or dirty. As can the fuel tank take in water ...
You may be running on 1 cyl, the right one ... maybe the vacuum line - the left carb only on a 94 has come loose.
Or you may have a general dirty carb ... you throttle cable likely not the issue ...

After all that ... even if its all perfect ...

You may just be lean ... idle hovering is sometimes that.

Cool.
Buddha.

Quote from: The Buddha on August 04, 2014, 12:49:35 PM
Yea air filter may be getting wet, and or dirty. As can the fuel tank take in water ...
You may be running on 1 cyl, the right one ... maybe the vacuum line - the left carb only on a 94 has come loose.
Or you may have a general dirty carb ... you throttle cable likely not the issue ...

After all that ... even if its all perfect ...

You may just be lean ... idle hovering is sometimes that.

Cool.
Buddha.

Is it a common issue for water to get in through the fuel cap? Are there options to fix that kind of issue?

The air filter is brand new though. And the carbs have been thoroughly disassembled and cleaned.

What do I do if it's lean?

Thanks for the replies.

I don't even own a cover for mine and its been rained on and ridden in the rain several times without any issues.


Does the bike have an aftermarket exhaust and/or air filter?  Either of those mods would make the bike run lean and require a rejet.

Carb boots split ..... Anyone? .. 

Carb boots splitting may cause that issue, but it will also be louder - a lot more raspy and rattly.
The lean mix, really wont keep it form revving past 8k either.
You may be super rich, with a float drifting high ... make that very high ...

Water in the gas can cause issues with general running, nit neccesarily @ high rpm. It will be more @ mid rpm ...

So - you may have a rip in 1 diaphragm.

Now remember carburetion is related to throttle position, not rpm. So if you only get to the same throttle position and encounter the same issue that = carburetion.

You may have a clogged jet - maybe a main (though pilots clog easier ... anyway maybe mains are clogged)
Cool.
Buddha.

Quote from: Watcher on August 04, 2014, 04:04:23 PM
I don't even own a cover for mine and its been rained on and ridden in the rain several times without any issues.


Does the bike have an aftermarket exhaust and/or air filter?  Either of those mods would make the bike run lean and require a rejet.

The exhaust is stock. Air filter is aftermarket but I put like 60 miles on it and it hasn't given me a problem.

Quote from: Janx101 on August 04, 2014, 04:21:10 PM
Carb boots split ..... Anyone? .. 

Carb boots have been replaced with new ones, but I'll check them by spraying starter fluid when the engine is running, and seeing if the rpm changes.

Quote from: The Buddha on August 04, 2014, 06:19:01 PM
Carb boots splitting may cause that issue, but it will also be louder - a lot more raspy and rattly.
The lean mix, really wont keep it form revving past 8k either.
You may be super rich, with a float drifting high ... make that very high ...

Water in the gas can cause issues with general running, nit neccesarily @ high rpm. It will be more @ mid rpm ...

So - you may have a rip in 1 diaphragm.

Now remember carburetion is related to throttle position, not rpm. So if you only get to the same throttle position and encounter the same issue that = carburetion.

You may have a clogged jet - maybe a main (though pilots clog easier ... anyway maybe mains are clogged)
Cool.
Buddha.

Both diaphragms have been checked, and no rips have been found. They look to be in great shape.

I'm not sure what you mean by that, but if I give it full throttle, it rises up normally but stops at 8000rpm.

The carbs have been cleaned quite thoroughly. I may give them a look again after I figure out if the coils are outputting the correct voltage and whatnot.


Thanks for all the replies so far, guys.