vm34 carb jets

[Triplecrown421]

motors pretty much stock has pipe intake mild port job ports matched from bottem to top im just wondering what a good starting point for jets at this set up??? carb came from old sled the jets must be close cuz the bike will start and idel amazing and the throttle response is awsome im waitin on a cable for it to ride but the engine revs fine. it had a 350 main for the machine before i just swapped out that for the blasters stock 240 jet but havvent tryed wide open. anyone know which way i should jet? or if this will be a decent for the job it was a freebee so keep that in mind. i plan on gettin it close here then using it for my dt200 stroker swap later.

 

[Braaaptor]

The VM's run well on a Blaster in my experiece, but the jetting will be a little leaner than with the stock 26mm Mikuni. That 240 main is about right. Id see what pilot is in there, but a #30 is close. Do some plug chops to see where you're at and go from there.

 

[Triplecrown421]

The VM's run well on a Blaster in my experiece, but the jetting will be a little leaner than with the stock 26mm Mikuni. That 240 main is about right. Id see what pilot is in there, but a #30 is close. Do some plug chops to see where you're at and go from there.

i just checked it i have a #35 pilot jet? ( do these go up an down by 1's or 5's? ) the main is actually a #250 jet. i got a magivered throttle cable on and tryed it out. got it up in the band acouple times and she sounds pretty torquie. cold after choke the motor idles awsome but after a couple minutes of idle it dies down some (kinda a surging idle) and if its givin a full throttle shock it bogs out till it can be winded up again to givein a good zing. if i pull the chock at idle it seems for a sec it runs more crisp but then gos too rich. sound to be too lean of pilot? what about the needle? what setup did you have?

 

[Braaaptor]

Personally, I'm running a 34mm Mikuni TM flatslide carb on my white Blaster (in my sig pic), but I had an orange 1999 Blaster with a VM carb on it. The carb I had on the orange Blasty came off of a Polaris Trailboss 250.

This bike was jetted WAY lean on the main when I got it, but after playing with the jetting and checking the plug, I was happy with a 240 main and a 30 pilot in it. IDK what needle was in there; I ended up trading the Blaster away before I got the carburetor tuned 100%. The engine liked whatever needle was in there well enough that I just ran it and made sure that it wasn't running lean by doing plug chops.

Mikuni pilots go up in increments of 2.5. For example, you can get a 30, 32.5, 35, 37.5, etc...

The Blaster I had with the VM carb had a stock jug with a 3mil Vito's stroker crank (w/spacer plate), Bill's pipe, and a lidless airbox with a UNI filter, if that helps you any.

It sounds like your Blaster is rich on the bottom end and/or not transitioning off of idle very well due to the needle currently in the carburetor. What needle are you running now?

 

[Triplecrown421]

the needle it has now is a 6f9 ? only numbers on it. im waitin atm for a cable an after that comes in ill be able to really test it. tryed it today again and the same thing motor ran beauteful at cold, after warming up the idle and start of throttle movement got foggy maybe to rich ill order a 30 pilot an give that a shot

 

[Braaaptor]

Sounds good! Get a proper throttle cable in there, try the re-jetting, and see how it runs. You've got a 6-series needle in there. The "6F9" needle description is all you need.That's how Mikuni labels their needles. Its somewhat confusing, so should you need to swap in a richer or leaner needle, here's the chart to help you pick out the one you'll need:

http://www.sudco.com/vol33/56-59.pdf

You can install any 6-series needle in your VM carburetor without a problem. You just can't install a shorter (5-series) or longer (7-series) needle. Hope that makes sense!

 

[Triplecrown421]

right on that site will defiantly help, i was lookin around and found a " 6dh4 " needle aswell which will work abit different. im lookin forwaard to how this works.