I thought I would pull this thread from the newbie section and continue it here. I got the bike home and finally got a chance to play with it, I pulled the tank and hooked up an auxiliary tank with a T fitting and got the same poor running -starts on choke but dies with any throttle opening or choke disengaged-. I applied vacuum to the petcock and fuel flowed well. After this I moved to another project for a while.
I did a number of trouble shooting tricks but wasn’t really keeping track, but here is the sequence I think I did.
I started it again with the aux tank on and this time plugged the vacuum line and it revved up like it should! WTF?? I put the tank back on and tried again, started it with the petcock on reserve with the vacuum line and it went back to original poor running condition. I pulled the vacuum line and as soon as I did it started running well again.
The problem is, now it started pouring fuel from somewhere on one of the crabs. I cut it off, dried the gas and for some reason decided to blow into the petcock vacuum line. I tried it again and it seems the fuel leak has stopped, but it still runs poorly if I attach the vacuum line on the petcock or don’t plug the vacuum line if it is unplugged.
It also started rattling from the rear cylinder at high RPM, I decided now might be a good time to add fresh oil and filter. As I feared, I think there was gas in the oil so it's definitely a good time to change the oil. I now know that it has a mechanical time chain tensioner as opposed to hydraulic so thinned out oil wouldn’t cause tensioner failure. I found the Grambo Trick write up and the Carb Blowback write-up.
My plan it to add fresh oil and filter, double check for vacuum leaks and do both of the tricks above. If the problems aren’t fixed by that, I will probably pull the carbs... I will also keep better track of my steps.
The tips I already received are appreciated and any more advice or tips are also appreciated
Originally Posted by Betteron2wheels
I'm picking up new-to-me '94 today. The previous owner(PO) did a lot of the fixes such as using the correct grease on the DS splines and a few electrical system mods. I checked it out last week, got it to start with the choke on but it dies if the choke is cut or any throttle is applied. He says he cleaned the carbs but the problem persisted. My 1st step will be to wrestle the carbs off, take them apart and ensure all of the parts are there, give them a complete cleaning including a sonic bath and hope that does the trick. Other than that it's pretty clean, the tank is rust free on the inside but has a couple of dings, it has a wind screen and saddle bags and he gave me an inch+ thick folder with new part receipts and maintenance history.
I haven’t had a chance to get through this forum to discover all of the easy mods but it already seems like there’s plenty. Looks like it’s going to be a fun bike, it might be just the right size for the fiancé.
Welcome to the forum !
As for your issue...check the idle screws on each carb. The might be turned in too much. Also check for vacuum leaks. The petcock is vacuum actuated, and may not be allowing enough fuel to flow...heck...check the flow first....disconnect the center thin hose from the carb (vacuum liine)..attach a longer one of same diam...remove the fuel lines one at a time and suck on the hose (you wont get gas in yer mouth)...this will show you the fuel flow. If its fine, search for a vacuum leak.
Also, there is a black, knurled plastic knob on the left side by the carb. Thats an idle speed adjustment.