Great site - 1st post! I pulled my 72 t500 out and got her running after sitting for many years. I flushed the tank, new fuel lines, new 2stoke oil, rebuilt both carbs, new intake boots, new plugs and regapped the points.
It stared 3rd kick! it leaks fuel from one cylinder at idle. When I took it for a ride it doesn't have much for power until the rpms come up. Although it idles well on both cylinders, it seems to be flooding on one. I removed the carb and the float was perfect at 27mm. I raised it to 29mm to see if that improved it but it did not change anything. the needle seats are new and not leaking.
Where do I go from here? thanks.
Last edited by Rocket350 on Sun Sep 13, 2015 12:50 pm, edited 1 time in total.
Last time this happened to me, a float had a pin hole in it and gas was pouring out of the header. Even if you're setting the proper float height this could be the case and the needle won't seat... Good luck!
I pulled the plugs and both were very wet so I think it's running super rich on both cylinders. I did a compression test and both cylinders are a 130psi. It smokes a lot. I can fill my garage with smoke in one or two revs.
It must be something with he carbs. I don't know how they can be assembled wrong... air screws are backed out 1.25 turns and does not seem to make much of a difference however much I adjust them.
Nope. I purchased two kits off the internet for 30 bucks, so I'd have to say they are knockoffs. It seems like its doing what it did 14 years ago when I knew the seats were leaking. I'd go though plugs like crazy. I guess I'll have to look for OEM needle and seats. Dang...
You are the man! I just ordered them. I've owned this bike since 1994 and has not ran since 2001. Hopefully these seats cures my flooding problem. thanks.
ConnerVT, I was reading a previous post about a guy having problems starting his flooded t500 and you said "Combine that with a leaky petcock and worn float needles, you can put quite a large amount of fuel in the crankcase."
My petcock is leaking. My seal with the 4 holes comes in on thurs so I thew in an O-ring to seal it for now. Fuel constantly runs no matter what the petcock is switched to (because of the O-ing). I clamp the fuel lines when the engine is off. Will the petcock really cause flooding while running?
Let's assume you (likely) have two failures. One being a leaking petcock, the second being a leaking float valve. How they behave would depend on how badly each one leaks.
First, with engine not running. If only one of the two were working properly, you would have no overflow. Either the petcock would stop flow to the carb, preventing supply of fuel to leak past the float valve.
Next, with the engine running. The petcock would be open anyway, so the only thing preventing the carb bowl overflow is the float valve. So, with the engine running, the petcock is not the cause of overflow.
However, you need to remember that the 1972 carbs are internally vented. So when the bowl overflows, it drains to the intake side of the carb. I have drained a significant amount of fuel out of my crankcase when I had my float valve issue. You could smell the gas with the bike in the garage, but no visible sign of leaks. The gas in the crankcase would (eventually) be forced out through the exhaust. Or (if bad enough) could hydrolock (trying to compress the liquid in the crankcase during the piston's downstroke).
