Had GS for 1 week.
Problem: After a few minutes of riding a conditioned of what I would call "over revving" happens. That is when I changed gears up or down the rev needle would climb a bit before starting to drop(this is while the clutch is in).
I took bike to get fixed, mechanic said he could smeel lots of petrol and could hear that air was being sucked in somewhere, also he noticed the choke was engaged, all be it the choke itself was seized and did not move at all.
He serviced the carbs and retuned them. Fixed the choke. All seemed well. He told me i would hear a popping sound from the exaust this is because the tappets need doing on the exaust side of the engine.
Anyway... I rode the bike home and it went well, I only live 3km away. the next day when I went for a ride after a few minutes of riding i came to a set of lights and was in neutral and for no reason the bike just starting revving at 4k and stayed there. Luckily the lights went green, The next set of lights the same thing.
I pulled into a side street, againg 4k revving. I turned bike on and off a few times and it went back to idleing at 1.3k so I adjusted the idle screw about 8 turns and it went to about 1.1k
I basically spent the next 15 mins riding around caining the ass of it trying to reproduce the 4k revving at idle but it didn't return, i dunno if the problem was with the idle screw or not???
Today I went for a ride(was going to beach) it was 39c or 102F. After a few minutes of riding the bike blurted & spurted then promptly died. The only way i could get it going again was to put petrol knob on prime (not reserve or fuel, the other position) once riding i would put it on fuel. After a few minutes of riding it would splutter and blurt then die... I did the same thing to get it going but put it on Reserve. same thing after a few minutes it would blurt and die.
I limped the piece of crap back to mechanic he checked all the hoses to carb, something about vacuum hoses being ok. Could only guess that it was due to hot weather, or something in hoses from the tank to carb, or when i get tappets done he said it would be work ok....
I don't think this fella knows what he's doing.
Even after he serviced the carbs the bike still revved wrong. When I first start bike up it rev ok, the rev drops back at a normal speed. After a few minutes of riding though if I rev bike say to 8k it takes about 2-3 seconds for the revs to drop. Also changing down gears doesn't seem to slow me down much, the bike just seems to want to stay revving to about 3k while in gear.
What could be the problem, and would fixing the tappets likely to solve the problem?
cable routing could be part of the issue, i know for some time my choke cable would pull tight just alittle makeing the choke come on alittle bit, and it would either stall,or rev up alittle. Vacume leaks(sucking air) could also cause some of this. Find someone you know who rides, and see who they use as a mechanic.
Note...
Iv'e been scowering the net for answers and may have come onto something.
1st a bit more on my problem... This over reving I get when changing gears appears to happen at low rev, say below 7k. That is if I change gears up or down below 6-7k the rev needle will bounce up and then take a while to come down.
I have noticed that if I accelerate hard, above 7k the rev acts normal, that is when I go to change up the rev needle will drop instantly a bit thus allowing me to change gears normally without that over reving feeling.
I have been reading on carb theory and from 1st glance it seems there are 3 jet systems in a carb.
Pilot jet = supplies fuel from idel to 1/4 throttle
jet needle and needle jet = affects carburetion from 1/4 thru 3/4
throttle.
Main Jet = 3/4 to full
Damn! I think I have a pilot jet problem??? As this over reving is very noticable at below 6k when i change gears making me sound like a novice when changing gears, but above 6k i change gears like a pro :)
But would this pilot jet problem be what was behind the problem i had when at set of lights all of a sudden the bike roared to a rev of 4k and stayed there? Maybe pilto jet is stuck open???
Also could this be behind not helping me to slow down when i use gears, example the bike wants to stay at 3-4k when i am in 3rd gear going down a slight hill but i am trying to get engine to slow me down rather than use brakes all the time?
Could this needle jet be causing my bike to stall when i was riding today?
Note...
Iv'e been scowering the net for answers and may have come onto something.
1st a bit more on my problem... This over reving I get when changing gears appears to happen at low rev, say below 7k. That is if I change gears up or down below 6-7k the rev needle will bounce up and then take a while to come down.
I have noticed that if I accelerate hard, above 7k the rev acts normal, that is when I go to change up the rev needle will drop instantly a bit thus allowing me to change gears normally without that over reving feeling.
I have been reading on carb theory and from 1st glance it seems there are 3 jet systems in a carb.
Pilot jet = supplies fuel from idel to 1/4 throttle
jet needle and needle jet = affects carburetion from 1/4 thru 3/4
throttle.
Main Jet = 3/4 to full
Damn! I think I have a pilot jet problem??? As this over reving is very noticable at below 6k when i change gears making me sound like a novice when changing gears, but above 6k i change gears like a pro :)
But would this pilot jet problem be what was behind the problem i had when at set of lights all of a sudden the bike roared to a rev of 4k and stayed there? Maybe pilto jet is stuck open???
Also could this be behind not helping me to slow down when i use gears, example the bike wants to stay at 3-4k when i am in 3rd gear going down a slight hill but i am trying to get engine to slow me down rather than use brakes all the time?
Could this needle jet be causing my bike to stall when i was riding today?
My bet is the valve tappets. Mine had the exact same behavier and was finally cured when I replaced all four shims.
See this thread to see how I did it.
http://www.gstwins.com/forum/viewtopic.php?t=6379&highlight=valves+carbs+emmisions
Along with JohNLA's info, I wonder if the recent thread GS Revs down real slow (http://www.gstwins.com/forum/viewtopic.php?t=6815) would be of any help to you.
The
sudden revving at the stop light makes me think that a particle of some kind lodged in a jet or in a float needle orifice, limiting the flow of fuel and causing an abrupt
lean condition. I know it sounds backwards, but somehow having LESS fuel in the mixture can cause the engine to overrev.
Do you know if the mechanic actually
cleaned the carburetors? If he did, I would suspect dirt or rust somewhere else in your fuel system (fuel tank, fuel hoses, ON / RES / PRI fuel selector). Use a good flashlight to inspect the (inside) bottom of your fuel tank. If it's been rusting it will be fairly obvious.
Also, you said you've had the GS for a week. Have you run through a tank of gas yet, or are you still burning through the stuff that was in it when you bought it?
If you're up to pulling the side panels and the fuel tank, you can check the throttle cable adjustment yourself. You
could do the following steps "blind" as well (without removing anything) just by monitoring the RPMS. You want to:
1) Get the engine warmed up.
2) Turn the idle screw out so it's not restricting the cable movement when the throttle is OFF. (If the tank is out of the way you can SEE what's going on at the throttle linkage, rather than guessing.)
3) Adjust the cable length (either at the carb or the handlebar) so the idle is a little
below 1200 RPM.
4) Turn the idle screw back in until it brings the idle up to 1200.[/list:u]I think I was going to write more, but I've forgotten what I was going to say.
Bike again today(Sunday) started to die after a few minutes of riding. Took bike back to mechanic, he blew in some petrol hoses and checked vacuum hoses, all ok.
took petcock apart and the diafram had black gunk covering the wire mesh filter part of it.
Unfortuneatly problem not solved. He used compressed air to clean the diafram and petcock. Blew into the petcock but air was being obstructed somewhere when vlave was in fuel or reserve position.
At any rate he cut the whole petcock out of the system now, put some kind of inline valve (looks like a garden hose valve). It has an on or off. He pluged up 1 of the petrol hoses (i hope the main fuel line) with a screw and clamped it off. completely removed a vacuum hose.
It fixed the dieing problem.
When I get some money i'll have to chase up a new petcock or at least the diafram for it. How hard would getting a diafram be, just a matter of going into a Suzuki bike shop and getting 1?
John - Yep he cleaned the carbs, I don't know if he did anything else like replace rubber parts or not?
Inside the petcock i noticed a rust stain :(
Now that the petcock is completely removed I will clean it up.
Damn! I hope riding around without a petcock or vacuum system won't screw the engine????
won't hurt a thing...of course if you run out of gas, there is no reserve. A lot of people on the board get petcocks very similar to what was put on your bike to solve some fuel starvation problems with the original suzuki equipment. You might want to look at replacing it permanently with a simple mechanical switch. Some people buy the Pingel one, or steal a mechanical petcock off of another bike. Just remember to turn it off when you park the bike. The fancy vacuum switched suzuki petcock evidently has problems with fuel delivery, although mine has been fine even on extended trips at high rates of speed.
Did you ever get your higher revving problem fixed? I think I am experiencing this also. After awhile the bike decides to stay at about 4k RPM like it is idling there. Occaisionally it will come down on it's own. Othertimes, I need to drop the clutch in 1st gear.
What was your fix?
ASLAM.
That 4k thing happened to me once over a few minute period. I turned the idle screw down and havn't had that problem of idleing at 4k again...
It still over revs during gear changes below 6k :(