new problem

[streetfighter]

this is frustrating, after i bought my bike and did a shim job and a valve adjustment on it it seems to run fine now a new problem occurred especially on lower revs!!!!
it seems to idle fine but if u leave it for a while it kinda dies and sometimes when u rev it and take ur hand off the throttle it kinda keeps revving and slowly goes down its weird, me and my brother who is a bike technician tore the bike down yesterday cleaned the carbs again and again checked the tank for any rust or any dirt that might have went threw the carbs we drained it checked the filter in it, everything seemed clean, put it back all together and problem is still there, we noticed that when the bike is a bit warm, we let it cool down and strated it again, the problem was still there we played with the idle needle and the throttle cable but it still was there!!!!!! helpppppp any ideas any reasons???

[lawman]

Sounds like a gas issue to me...

you checked the carbs - what do the plugs look like?

Did you look at the fuel lines (odd I know), or more importantly, the petcock?  does it do this if you're in prime, or just "on?"

have you checked your carb float heights?

[streetfighter]

Sounds like a gas issue to me...

you checked the carbs - what do the plugs look like?

Did you look at the fuel lines (odd I know), or more importantly, the petcock?  does it do this if you're in prime, or just "on?"

have you checked your carb float heights?

can somebody post a picture that shows the correct wiring of the hoses that go from the tank to the petcock?? it doesnt hurt to be sure
spark plugs are brand new i dont think they are the problem nor the carbs, float height is good

[lawman]

can somebody post a picture that shows the correct wiring of the hoses that go from the tank to the petcock?? it doesnt hurt to be sure
spark plugs are brand new i dont think they are the problem nor the carbs, float height is good

There's a picture here somewhere... http://www.gstwin.com/fuel_hose_routing.htm

look at the color and condition of the plugs.  Will tell you too rich, too lean, too hot, etc.  Not that there's a problem with the plugs, but with their environment...

[streetfighter]

can somebody post a picture that shows the correct wiring of the hoses that go from the tank to the petcock?? it doesnt hurt to be sure
spark plugs are brand new i dont think they are the problem nor the carbs, float height is good

There's a picture here somewhere... http://www.gstwin.com/fuel_hose_routing.htm

look at the color and condition of the plugs.  Will tell you too rich, too lean, too hot, etc.  Not that there's a problem with the plugs, but with their environment...

thank you will check it out

[fred]

That sounds like a vacuum leak to me. You are probably missing one of the tiny orings in the carbs. You might also have a cracked intake tube... My project bike had both of these problems at the same time and had huge idle floating problems...

[lawman]

That sounds like a vacuum leak to me. You are probably missing one of the tiny orings in the carbs. You might also have a cracked intake tube... My project bike had both of these problems at the same time and had huge idle floating problems...

I thought that, but in my experience vacuum issues cause racing rpms, not dropping rpms.  It's worth checking that with a can of wd40 or starting fluid, in any event.

[streetfighter]

we found which seems to be the problem, there's no vacuum leak but we think the air/fuel mixture screw must be adjusted because we see sometimes smoke coming out of the muffler and sometimes smell gas, we think its running lean, it gonna go on the dyno soon to get diagnosed and fixed up if anybody interested to see some dyno curves let me know ill post some pics

[Affschnozel]

........ if anybody interested to see some dyno curves let me know ill post some pics

Come on post them up , we all love dyno curves and others 

[ohgood]

we found which seems to be the problem, there's no vacuum leak but we think the air/fuel mixture screw must be adjusted because we see sometimes smoke coming out of the muffler and sometimes smell gas, we think its running lean, 1) it gonna go on the dyno soon to get diagnosed and fixed up if anybody interested to see some dyno curves let me know ill post some pics

1) oh no ! your gs will be destroyed in 3, 2 ,1 ... (no, really, dyno's are a terrible thing ! )
2) you might be quite rich, hence teh smell of gas and puffs of unburnt fuel. check out your float levels, and make sure your floats... float

there was a thread just a month ago about putting a gs on a dyno, and how the engine was destroyed. most dyno operators look for peak rpm/power instead of just tuning the mixture. looks real impressive to get another 10-15 HP for some people. you won't see this on a gs. well, unlesss you unplug a spark plug for the first run.

skip the dyno, check for vacuum leaks and float height, make sure you're getting fuel through the float bowls, and hey, the ignition system (coils stuff) usually is the hiding culprit for what seems to be fueling issues.

also, flush the tank/carbs with fresh gas from a normally good source. bad gas has sent plenty of carburated motorcycle owners to the poor house.