Engine cranking and jumping to 2000 RPM

[Sarcvicious]

After months and finally giving up chasing electrical ghosts, we rewired the bike, added some carb cleaner and the bike is now cranking and turning over. Something isn't set right on the carb because the throttle seems to be wide open the second the bike starts and the bike is trying to run at 2000 RPM and shooting white smoke from the stock exhaust. We played with the adjustor screw, the idle jet adjustors and we had the idle running well for about 20 seconds, but then the RPM revs up and its shooting white smoke by itself again.

The bike hasn't run since the 90s so this is awesome progress on the GS650.

Unfortunately it looks like the carb assembly tutorial (linked below) is no longer available. Does anyone have a tutorial? Im not sure how to connect the choke cable, throttle cable & im not sure how to set the adjustment screw that sets how far the butterfly screws can close. Obviously I can't sync the carbs correctly until we can get the idle correct.


http://zeus.mtsac.edu/~cliff/storage...d_Tutorial.pdf

Also of note, I have the dyna S ignition (timing is not set), green dyna coils, carbuerator is already jetted using dynajet pilots etc. Carb has been properly cleaned, and installed new float screws/ checked levels. New diagphram boots on all carbs. Brand new spark plugs and brand new spark plug wires. Engine compression good. (4: 150, 3: 150, 2:142, 1:155)

Petcock is not connected since we dont have a tank on yet. We're funneling gas into the carbs through the fuel line. Have not checked valve clearance yet.

 

[tom203]

Did you replace the o- rings at carb boot/ cylinder head interface ?
Send a PM to member Nessism…..he might have a working link to his carb rebuild .

don’t put off valve checking and adjustment…this is critical.

 

[93Bandit]

Nessism's CV carb rebuild tutorial https://gsarchive.bwringer.com/mtsac/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf

 

[Guest]

If you haven't checked valve clearances, don't even think of trying to sync the carbs.

 

[Lou]

After months and finally giving up chasing electrical ghosts, we rewired the bike, added some carb cleaner and the bike is now cranking and turning over. Something isn't set right on the carb because the throttle seems to be wide open the second the bike starts and the bike is trying to run at 2000 RPM and shooting white smoke from the stock exhaust. We played with the adjuster screw, and the idle jet adjustors and we had the idle running well for about 20 seconds, but then the RPM revs up and it's shooting white smoke by itself again.

The bike hasn't run since the 90s so this is awesome progress on the GS650.

Unfortunately, it looks like the carb assembly tutorial (linked below) is no longer available. Does anyone have a tutorial? Im not sure how to connect the choke cable, throttle cable & im not sure how to set the adjustment screw that sets how far the butterfly screws can close. Obviously I can't sync the carbs correctly until we can get the idle correct.


http://zeus.mtsac.edu/~cliff/storage...d_Tutorial.pdf

Also of note, I have the dyna S ignition (timing is not set), green dyna coils, carbuerator is already jetted using dynajet pilots etc. Carb has been properly cleaned, and installed new float screws/ checked levels. New diagphram boots on all carbs. Brand new spark plugs and brand new spark plug wires. Engine compression good. (4: 150, 3: 150, 2:142, 1:155)

Petcock is not connected since we dont have a tank on yet. We're funneling gas into the carbs through the fuel line. Have not checked valve clearance yet.

I am new here and to this stuff as well but here is a little suggestion please correct me if I am wrong. By the white smoke, I guess your fuel adjustment is out as well or your head gasket is gone too. check for the leaking around the head seal or open the engine oil cap and look for any smoke.

To start it, here is a quick vid, https://www.youtube.com/watch?v=7DgpMHp7XEo all basic but would be helpful https://www.youtube.com/watch?v=k5bVh_MKGRk. if the RPM is shooting at 2000 then you can try closing the idle screw to the end until the bike starts dying without the race and then open it by half cycle until the RPM gets stable. then I think there should petrol adjusting screw somewhere, close it down and open it 1 and a half cycles later, and adjust it as per the MPG reading. It should take care of the white smoke from the tail if not then you need a new gasket or the valves may have leakage. I hope it will help.

 

[Sarcvicious]

Thank yall for the back up. Ive been debating with my partner telling him that we need to check the valve clearance and he was determined that we needed to sync the carbs first. (No need trying to win a fight with a woman. We're always armed with information to be right. Even if we're not right HA)

 

[Nessism]

If the valves are tight, it will invalidate the sync.

 

[Sarcvicious]

I checked the valves. They're all tight. Glad I didn't waste time trying to sync the carbs prematurely

 

[rphillips]

Ain't listening handy, can save lots of time & effort.

 

[Sarcvicious]

Nessism's CV carb rebuild tutorial https://gsarchive.bwringer.com/mtsac/~cliff/storage/gs/Mikuni_BS-CV_Carburetor_Rebuild_Tutorial.pdf

Alright, now im having issues getting that PDF to download. Anyone able to download this? I need to save it to my computer.

 

[Grimly]

Alright, now im having issues getting that PDF to download. Anyone able to download this? I need to save it to my computer.

It's downloading flawlessly here.

 

[Rich82GS750TZ]

I dowloaded Ed’sCV carb tutorial and put it on my Google drive. Try this link. https://drive.google.com/file/d/1NJYGqj4K0d-1J4oCu0cMLmNcvL5Q1Is5/view?usp=drivesdk

 

[Sarcvicious]

Thanks guys. Its working well and now I have the document saved/

So I checked the clearances, changed shims, rechecked clearances, installed a new gasket on the generator cover, and a new gasket on the cylinder cover and the breather cover.

The bike isnt starting up now, and instead just cranking and making a few pops. With the throttle wide open carb 3 is smoking, and using carb start all 4 will pop, but the bike wont start up. I saw that someone had actually cut a breather cover gasket and added a filter to it... his bike must have been a 750 or 850 based on what the stock gasket looks like. My breather cover gasket is a solid gasket. This wouldnt be restricting the airflow so much that the bike wont start would it? The previous owner did not have a gasket on this at all. Still getting good spark and the battery is fully charged.

reference-
gs 650 gasket- https://www.ebay.com/itm/2912304458...WonvJQnX_1U36FPiU7caXxZqqUD71HMxoCbzMQAvD_BwE

gs 750/850 gasket- https://www.ebay.com/itm/391955939707?chn=ps&mkevt=1&mkcid=28