Motorcycle Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
Purchased this bike on ebay without ever seeing the bike; a bad mistake. I have had it over a year and it will not run correctly on the LH cylinder. It runs rich on that side. It will idle smoothly on the left side with the pilot air screw out about 2 1/2 turns but loads up when given throttle off idle. If I pinch off the fuel tube for the LH side it will rev smoothly after 30 seconds or so. The pilot jet, needle and needle jet have the correct numbers on them and the jets do not appear to be drilled out. I have new OEM points and condensers (NOS) and I have mounted a set of DYNA coils. I have reset the float level several times; even setting it lower than spec with no change. I have checked to make sure float needle is shutting off by blowing air (by mouth) through the inlet. I have also replaced the LH outer crank seal with a new seal (also NOS); the old seal was brittle but not showing any leakage. I have not pulled the top end and am now suspicious that someone has been into the engine and either screwed up something or carved on the piston or cylinder. Is this worth doing or is my problem still with the LF carb. Thanks, Bob
 

·
Ghost in the machine
Joined
·
2,857 Posts
Is it possible that the intake boot (between carb and cylinder) has dry rot cracks? Easy test is to spray starting fluid or WD-40 on it while running. If the rpms change, it's leaking.

I agree with Hammer. Start with a compression test.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #6
Compression 127# LH cylinder 134# RH cylinder (manual said 114-128) no leaks on intake boots. Will go through LH carb one more time and try to determine if needle jet has been fooled with.
 

·
Ghost in the machine
Joined
·
2,857 Posts
What do the spark plugs look like? Does the needle have an adjustment c-clip, positioned the same as the carb on the right?
 

·
Registered
Joined
·
6 Posts
Discussion Starter #8
Can't ride it far enough to get a good plug reading....both needle clips in the center groove. Found some new info online on the VM34 Mikuni Will go through both carbs again before I do anything drastic
 

·
Registered
Joined
·
6 Posts
Discussion Starter #9
Problem solved! Thought I would share. Wrong main jets! The bike had 150s in it when I bought it. The KEYSTER rebuild kit I bought for it also had 150s. So I ASSUMED that 150s were correct. I just knew something was not right so before I tore into the top end I decided to do some more research. My T500 is a 1975, turns out it is supposed to use 97.5 mains. Picked up a pair at bike shop and put them in. Runs 100% better; now just some fine tuning (may raise needles one notch) and I will have it. Thanks all!
 
1 - 10 of 10 Posts
Top