Carb problem

[downeaster]

Hey all, Im having a carb issue and was hoping some one could point me in the right direction. I have a 8 valve GS 750, stock exhaust and airbox with a KN filter. The valves are all within spec's on the loose side. Last fall I put new intake boots and o-rings. I just got a o-ring kit for the carbs and am planning on taking them off and dipping them next weekend. When I start it cold it wont stay running on the choke. I have to use it to get it to fire up but the it dies. then it will start but not with the choke, I have to keep it going with the throttle until its warm. when I was adjusting the air screws, seating them and turning them out to the highest idle the number one carb doesn't change anything. that exhaust pipe is slower to get hot also. I checked and the tip is not broken off the screw. All the fuel screws on the bottom are turned out 7/8 of a turn ( I read that that's a good starting point, but I really don't know). What should I be looking for when I get them off? I Know obviously something must be plugged. Any advise would be greatly appreciated. thanks

 

[hillsy]

You have blocked pilot circuits if the idle mixture screws don't change anything.


Dipping the carbs? Carb cleaner and compressed air to blow out the fuel circuits is your best option.


Go to GS Resources and check what your carb specs should be.

 

[downeaster]

Ok, thanks Hillsy. GSR is were I read that 7/8 of a turn out on the fuel screws to start. How can you tell when you have it right? Keep checking the spark plug?

 

[crazypj]

If the bike hasn't been run in a long time (or maybe even if it has?) you would be far better off stripping everything out of the carbs.
Just 'dipping' them is likely to make things work short term but long term it really screws up various seals and nylon washers.
You have to remove the slides and float bowls, floats and shut off valves even if you are just going ahead with a carb soak

 

[DohcBikes]

Are you positive that your ignition system is performing flawlessly?

You do have carb issues, but there's no need to chase them if you also have ignition issues. According to your symptoms, some tests are in order.

 

[downeaster]

Crazypj, I ran the bike all last summer and I was planning on stripping the carbs before i dipped them, and have new o rings to put in. and DOHC, I have spark on all cylinders but as for working flawlessly, i dont know. I put new points and condensers in last fall and timed it and it seemed to be ok. I put together a coil relay but haven't put it on yet.

 

[goldy]

Carburetor and ignition problems often exhibit the same symptoms...by all means thoroughly strip and clean your carbs. You may want to consider replacing the K&N with the stock filter, these things are remarkably sensitive to mods made to the intake tract. Dohc may be onto something..the ignition relay mod may make a huge difference in the way the bike starts...makes sure that you have full battery voltage going directly to the coils. It's also a good idea to remove and meter your spark plug boots, if they are not within the std OHM range, you will be doing yourself a big favour replacing them. I have always found these machines seemed to work better with about 2 turns on the idle mix screws.

 

[downeaster]

I have put on new spark plug boots. I think I will do the carbs and the relay and go from there. The three idle mixture screws that work ended up being 1 3/4 to 2 turns. Hopfully I will get a chance to work on it this weekend. I appreciate all the advice, thanks