Need ideas? Project bike won't run....

[cbrfxr67]

Don't give up!  I hope you keep at it!  These are the best threads on the forum if you ask me.  Can't wait to see the outcome.  Good luck to you!  I'd comment but I don't know jack about GS carbs except mine are in a plastic bag next to a dismantled engine.

[craigs449]

Went to the Ace hardware store near me and found the closest o-ring size.  Before work I put them on the needle seats and pushed them little suckers in there....Boy they are tight with the new o-rings.  After a bit of wiggling and pushing, I was able to get them far enough in the carb that the plastic tab on the bowl does not hang up on it.  ran out of time and had to go to work, so I will have to get back around to it hopefully Wednesday. 

thanks for all the help so far 

[craigs449]

Kinda at a standpoint now........put the new o-rings in the needle jet seats and still having the same problem.  Bike will start and run initially, then stall out.  When I crank it, I am getting lots of gas coming out the intake side of the carbs into the airbox.  If I unplug the vacuum line from the carb and put the petcock on "prime", it will start after a bit and idle.  If I blip the throttle, the bike will stall.....also when it is idling, there is a "PSST" sound that seems to come from the right side carb and it seems to come out of the airjet hole in the intake side of the carb.  I do like project bikes, but this one seems to be a doozy!  The basics seem to be there, fuel, air, and also strong spark on both sides...........what am I missing at this point?  I would assume that a compression test for each cylinder would be the logical thing to do next?  Anybody know offhand what the proper compression range should be for a 2001 GS 500?

[Jared]

Compression should be 142-199 PSI according to the clymer manual.... That's with the bike warm.  114 PSI is the service limit and 28 PSI between cylinders.

Did you get new float needles/seats yet?

[craigs449]

Compression should be 142-199 PSI according to the clymer manual.... That's with the bike warm.  114 PSI is the service limit and 28 PSI between cylinders.

Did you get new float needles/seats yet?

Gotta order the needle valve/seats from OEM......Can't seem to find a rebuild kit for this model......There is no way I can get a compression reading with the bike warm, I can't seem to keep it running long enough to get warm !  That "PSST" sound is what really has me wondering..............

[Big Rich]

Even a cold compression test will be helpful. It would show any difference between the 2 cylinders and if it's really low on one side.

Craigs, any time there is a sound coming from the carb itself it is usually from a lean mixture. But you said that plug was wet with gas, correct? And just as a run-down:
Are the jets the stock sizes for the year you have?
Any intake/exhaust mods?
I'm guessing you have the carb intake exposed since you are messing with it?
Air/fuel mixture screw isn't drilled out or if it is, is the tip of it snapped off?

With all the info you've already given, I really don't think it's a carb issue (and you said you know your way around carbs, and I believe you). That's why I asked about the spark and the battery - a weak battery can cause havoc on tuning, and spark can be a hard thing to diagnose sometimes. So assuming the carbs are in top shape and the valves are within spec, I would try to switch the left and right coil AND spark plugs to see if the problem switches to the other side.

[craigs449]

Even a cold compression test will be helpful. It would show any difference between the 2 cylinders and if it's really low on one side.

Craigs, any time there is a sound coming from the carb itself it is usually from a lean mixture. But you said that plug was wet with gas, correct? And just as a run-down:
Are the jets the stock sizes for the year you have?
Any intake/exhaust mods?
I'm guessing you have the carb intake exposed since you are messing with it?
Air/fuel mixture screw isn't drilled out or if it is, is the tip of it snapped off?

With all the info you've already given, I really don't think it's a carb issue (and you said you know your way around carbs, and I believe you). That's why I asked about the spark and the battery - a weak battery can cause havoc on tuning, and spark can be a hard thing to diagnose sometimes. So assuming the carbs are in top shape and the valves are within spec, I would try to switch the left and right coil AND spark plugs to see if the problem switches to the other side.

Yup, the right side is the side that the sound comes from....almost like someone is blowing air back out of the air jet hole on the intake side of the carb.  the right side plug is also the one that is wet with fuel.  I have tried swapping the plugs to either side with the same results.  Eyeballing it, the spark looks equally as strong on both sides.

2001 GS 500
Bone stock, stock airbox/filter, stock exhaust, As far as I can tell, the jets are stock....(the ones that I can read are stock sizes, I can't read the others).  PO started to fool with the carbs when he couldn't get it started, so he drilled out the caps for the fuel screws.  Botht eh screws look good (is it possible that the o-rings for the fuel screws might be the issue?)  I have the tank propped up in its place and the air filter out of the airbox while I am trying all these things, so I can see the intake side of the carbs. 

I am using a jump box while cranking the bike so the power is there.  The battery is not great, but its easier to hook up the jumper box for steady cranking....

I am getting conflicting info on different websites........anyone know whether the needle valve/seats from a 2004-2006 carb will work with a 2001-2002 carb? The OEM parts fiche shows a different part # for them, but I see that some places have them listed as being used on both.

[craigs449]

Compression should be 142-199 PSI according to the clymer manual.... That's with the bike warm.  114 PSI is the service limit and 28 PSI between cylinders.

Did you get new float needles/seats yet?

Finally found needle valves / seats for this carb......Oldbikebarn said they cannot source these parts..

http://www.smebike.com/index.php?route=product/product&path=2_65_70&product_id=1070

[Big Rich]

Just fyi- oldbikebarn is a freaking rip off. It's one guy running a website out of his basement. You order something, then he orders it and gets it shipped to him, then ships it to you. Google "oldbikebarn reviews" and you'll see what I mean.

[craigs449]

Just fyi- oldbikebarn is a freaking rip off. It's one guy running a website out of his basement. You order something, then he orders it and gets it shipped to him, then ships it to you. Google "oldbikebarn reviews" and you'll see what I mean.

good to know.....i had one helluva time finding the seats/valve for this bike!  probably because they only used this carb on the 01 and 02 bikes.....i paid under $30 for both sets from the link i posted......oem was $45 per carb!  we will see when the parts get to my door...


-craig

[Jared]

I always use Partsnmore  but they don't have your  carb parts either.   Most places are resellers/middlemen- some stock some don't...Some Suck and some don't.

What's your schedule next week Craig?

[craigs449]

I always use Partsnmore  but they don't have your  carb parts either.   Most places are resellers/middlemen- some stock some don't...Some Suck and some don't.

What's your schedule next week Craig?

Going to visit my brother after Christmas for a few days, gonna take my 02 Honda CR 250 - smoker and do a little woods riding with my brother on his badass Can-Am Commander.  Also just picked up a Contour Roam camera that I have been itching to use