single VM36 tuning question.

[shark1979]

i have read some threads on here about this issue. i have had my 2 into 1 setup on my bike for a couple months now , still tuning this set up. i have changed the needle jet, needle. i am running a 30pj and 190 mj. the air screw is 2 turns out. the bike starts first kick. runs fine pulls hard all the way through. but i still have surge at low speed /low rpm. which means lean. Right? but if you read the plugs they are black. if i try to lean it out any it starts to pop and act funny. can you all offer any info to my problem?

 

[TampaSVT]

I have the same setup, but haven't gotten to the point of tuning it yet.

Joe (WiseGuy) says a 22.5 to 25 Pilot is about right. And, 190-200 main.

Have you tried the smaller pilot? And, what type of air cleaner are you running?


Rich

 

[shark1979]

I have the same setup, but haven't gotten to the point of tuning it yet.

Joe (WiseGuy) says a 22.5 to 25 Pilot is about right. And, 190-200 main.

Have you tried the smaller pilot? And, what type of air cleaner are you running?


Rich

i started out with a 22pj like Joe(wiseguy) said . i have worked my way up to a 30pj. i am running a uni foam pod filter. i have tried the needle all the way up and all the way down. still have surge. and plugs still end up black. the bike runs really god the way it is set up. On the down side the plugs read RICH, the surge tells me LEAN, and the really bad MPG tells me rich. the bike get 35-40 around town and maybe 45-50 on the highway.

 

[TampaSVT]

I'd trust the plugs and mileage more than just the "surge"...

You sure there's no cable binding or something else going on there?


Rich

 

[grizld1]

In a 2009 study sponsored by the American Association of Thumbusters, only 5% of carburetor problems identified were found to originate in a carburetor. 70% were caused by ignition defects, 8% were caused by worn cylinders, 10% were caused by incorrect valve adjustment. The remaining issues were nonmechanical in origin, traced to the actions of gremlins and poltergeists.

Inspect the above and have a look at the float level. You did get a copy of the Sudco Mikuni Tuning Manual so you'd know how to do that, right?

 

[xjwmx]

If what you're doing to the carb doesn't show results something like what you'd expect then there's another problem. Could be a bad coil, for example. I had the weirdest situation recently where there was a real carb problem with a bad float needle, but fixing it didn't fix my problem. I went through a process that told me it had to be a bad coil, which it was. Although the coil measured ok.... Obviously it was an insulation breakdown in the secondary winding causing a weak spark. No amount of leaning would not make dark plugs.

 

[shark1979]

I just replaced the piston , rings , had the head done, new pamco, new coil, plugs and wire. I checked the valves, and the timing . I will check the coil with a meter tonight. And I will pick up a couple new sets of plugs. And start this tuning process over from scratch

 

[5twins]

What type of UNI do you have? If it's the black foam pod and you used the normal foam filter oil, it may be clogged up and restricting air flow.