ON MY GS500E (1996) AT 6,000 RPM AND HIGHER IT SEEMS LIKE A GREAT LOSS OF POWER LIKE THE ENGINE JUST SHUTS OFF. I TRIED DRAINING THE CARBURETORS AND IT DIDN,T DO ANYTHING. PLEASE HELP ME OUT.
Sounds like fuel supply is poor. More details may help...does it do it all the time, if you accelerate fast does it do but not when slow, in all gears say its 6K in 6th, but 7K in 5th, and 8K in 4th..., rpm dependent or throttle position dependent dies at 6K or at 1/2 throttle independedn of rpm, Fuel level...Does it do it when tank is empty or all the time, petcock position - does it in on or res but not prime, ...Load dependent - does it do it in neutral when at a stand still and you rev it....
Cool.
Srinath.
Help!! Im having this problem and im 140 miles from home!!! I was searhing the site and found this!!! I seem to be having a power loss at higher sutaned rpm...........not when accelerating it seems like!!! But over all power loss!! When the tank is about a quater left or below the hbike just dies!!!!! I have it a WOT to do 80 in 6th also!! Help!! What could this be lack of fuel?? Has anyone had this problem??
Yes, Newbie, this is a common older GS500 problem.
It is likely fuel starvation, caused by a defective vacuum fuel petcock mounted on the frame under your left leg.
That petcock has a rubber diaphragm inside that gets old and leaks, and when that happens, the vacuum line won't hold the diaphragm open so the fuel will flow properly. Instead, the fuel is slowed or shut down and YOUR ENGINE DIES or acts like it can't get enough fuel. That's because it's not getting enough fuel.
For now, you can try putting the petcock lever into the PRI or prime position so fuel flows (though it is a smaller pipe so reduced flow) so you can make it home.
You will have to:
Replace the petcock with a new GS500 parts, about $60.
Replace the petcock with one from a Honda CR250F (about $30 and requires only slight modifications -- it won't have the vacuum operation anymore, which is a good thing)
Modify your existing petcock to get rid of its vacuum function, and it will work just fine. Again, requires slight modifications.
For the second two options, search here on the board for fuel starvation and you will find links to the previous postings.
All of these are easy fixes.
Here's a link to an earlier post:
http://gstwins.com/gsboard/index.php?topic=37129.0
Here's a photo of what the modified parts look like (see the post above)
http://www.bbburma.net/Temp/Jenya_petcock_plugged.jpg
Another related link:
http://gstwins.com/gsboard/index.php?topic=19363.0
Here's a link to the CR250F/CR450F Honda petcock replacement trick:
http://gstwins.com/gsboard/index.php?topic=34286.0
My 1991 GS500E did the same thing to me in 2004 on my home on a 600 mile trip from Boston. Not fun on the side of I-95 with trucks flying by.
I hope you made it home safely by now.
Let me know if you need more info or help.
Best wishes,
Yours,
Trwhouse :)
96 GS, start with the easy stuff. A battery that needs replacement will get to the point where it can't supply enough ignition current and it will act like a rev limiter. Do you have plenty of cranking power? If not, it's battery time.
If it's a fuel problem it won't happen at the same rpm every time. Put the petcock on PRI (prime) and see if that clears it up. If it does, your vacuum operated fuel valve isn't opening properly. Good luck!
Well guys made it home!!! YEA!!!..........Anyways did not die once on the way home, but seems like its way under power........im almost at wot to do 75 on the highway and the bike got like 30 mpg or less on the trip down, a tad better on the way home, the bike is a 07 so shouldnt i not have petcock problems??? I had the bike in to have the carbs gone thru and the orings replaced so there synched and i should be good there. I seem to have good cranking power but the head light does get brighter when the bike is reved but so does my other bikes so i geuss i thought it would be good.......ever since i got the carbs done it seemed like for the first 70 miles it was zippy but has just gotten slower and slower since??? So were should i start?????
BUMP!! Im at a loss??
A shop did the carbs and it lasted 70 miles - you think they didn't set the tank petcock open perfectly ?Cool.
Maybe you're vacuum locking the tank.
Also check for intake air leaks.
Check for extraneouos things the shop can screw up.
Betting its in the hoses and vents and petcock etc etc.
Cool.
Buddha.
The tank hose's and vents can cause the much of a power loss and poor millage??..................well i will take the tank off after work and reassemble and see what happens
I guess newbie gave up? What ever became of this? Did you fix this problem?