Thank you to all who posted problems and responses and links regarding poor running and fuel starvation. 

I'm doing a favor for a friend who let his '97 GS500E - totally stock - sit for the last 2 years.

I spent several hours pouring over the problems and responses posted on this site and came to 1 conclusion;  THE CARBS HAD TO BE CLEANED!!!!  No amount of fresh fuel or carb cleaner was going to stop gas from running out the airbox or carb overflow tube, make the idle return from stratospheric heights or make it just stop dying in mid flight. 

I must say that having to make corners at 35 to 40 mph to keep the R's up, was somewhat entertaining.

Having campained an RD350 in the "street wars" of the 70's, it made no sense to me to have to remove the carbs and all that linkage from the machine.

I knew I could remove the carb tops and rubber booties, so I decided to clean them.  The right diaphram was covered in gas.

I still didn't want to take all that junk OFF the bike so I made an offset screw driver from a 1/4 drive ratchet, a 1/4" socket and a phillips bit.  For extra clearance I removed the starter cover.

Float needle was stuck in the valve in the OPEN position.  Took it apart and cleaned it up, along with the pilot jet and other various orifices and put it back together.

So, I should check the left carb, no?  YES!!  (Besides I had to see how the little wire clip held the needle in the groove, so to speak...)

The LEFT float needle was also stuck - IN THE CLOSED POSITION.  Hence the massive hesitation and sudden high speed histrionics - the left cylinder was only getting fuel from the overflow tube from the right carb.  Also explains why the fuel leakage quit at highway speeds.

Bike now starts and modulates with the choke.  Idles at 1000-1100 when warm.  Starts with no throttle, goes, stops, all that stuff.

BTW:  Local Suzuki wanted $185 if you brought the carbs to them for the same job.

FUEL STARVATION AT SPEED:  The valve on the back side of the tank mounted petcock MUST BE ABSOLUTELY VERTICAL!!!!    I needed some gas for the lawn mower so I drained some from the tank sitting by.  While I was waiting for a suitable amount I screwed with the valve to see how far it turned.

Moving the valve only a few degrees off vertical in either direction DRASTICALLY REDUCED FUEL FLOW.  (Tank and fuel screen had been cleaned first).

MY CONCLUSION:  Before fitting new petcocks - make sure those tank on/off valves are vertical

Watch the valve adjustment video that Kerry made, it shows the fuel tap very clearly. 

h7

Welcome!

Glad you found the site useful!

Carb cleaner is really bad for rubber, better to remove the carbs (actually 2 10mm bolts (rear plastics), 2 12mm bolts (tank), 2 size 3 philips screws (airbox), and 4 #2 philips(airboots), plus the choke and throttle linkage (10mm)), and dissasemble them completely.

Quote from: gpage4130 on May 26, 2006, 10:03:00 AMWatch the valve adjustment video that Kerry made, it shows the fuel tap very clearly.

Thanks for the mention!    For anyone who doesn't have access to the video, here are a couple pictures of the fuel tap:


Camera on the left side of the bike, next to the engine, pointing rearwards:

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Camera on the right side of the bike, peeking between the frame and the top rear of the engine:

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Quote from: Kerry on May 26, 2006, 02:18:56 PM
For anyone who doesn't have access to the video, here are a couple pictures of the fuel tap:

Oh, man I was hoping they'd be panoramas!