Mikuni vm carb

[raydhd]

Another note I am using the Holley Mighty Mite electric fuel pump that is listed @ 1.5 - 4 PSI so the carb is under constant and steady pressure. I am routinely @ 5500 rpms so it certainly keeps up the flow. When I put the VM 38 on my HD ironhead which is gravity fed it poured fuel out of the overflows out of the box and the float height had to be adjusted.

[KRAZYMATT]

Flipped the carb over and opened the bowl to check float height. They were low around 20.5-21mm both. Adjusted both to right at 24. Put together and tried it. Couldn’t get anything. Opened it up and lowered them both to about 22.5. Tried again started right up and seems pretty good it I still have fuel running out of the overflow fitting the whole time it runs. Going to mess with it a little more over next few days if I don’t figure out I will just break down and put bypass/relief line back to tank. I’d rather not though if I can get this adjusted good

[Low-Tec]

Originally Posted by KRAZYMATT

Is it a whole different needle and seat or can it be achieved just by adjusting float height?

http://https://www.denniskirk.com/mi...prd/170459.sku

These are generally available in 1.5, 2.0, and 2.5 gallon per hour.
Remove your seat from the carb and look at the back end, it's probably stamped 2.5. Snowmobiles generally use the 1.5, the lower flow prevents the the needle from being forced off the seat by the pressurized fuel.
Makes any solution costing more than $18 seem pretty silly.

[KRAZYMATT]

Originally Posted by Low-Tec

http://https://www.denniskirk.com/mi...prd/170459.sku

These are generally available in 1.5, 2.0, and 2.5 gallon per hour.
Remove your seat from the carb and look at the back end, it's probably stamped 2.5. Snowmobiles generally use the 1.5, the lower flow prevents the the needle from being forced off the seat by the pressurized fuel.
Makes any solution costing more than $18 seem pretty silly.

Thank you! I think this maybe what I need. The carb I purchased - vm32-193 looks like it has a 3.3 gallon needle and seat according to the specs online. Will open again tommorow am to verify then I guess order the need and seat!

[raydhd]

Originally Posted by Low-Tec

http://https://www.denniskirk.com/mi...prd/170459.sku

These are generally available in 1.5, 2.0, and 2.5 gallon per hour.
Remove your seat from the carb and look at the back end, it's probably stamped 2.5. Snowmobiles generally use the 1.5, the lower flow prevents the the needle from being forced off the seat by the pressurized fuel.
Makes any solution costing more than $18 seem pretty silly.

Great info. I was not aware of these options for the seat. Makes sense why the sleds use pumps without overflow issues. Great thing about BGW you can always get more ideas on how to solve issues.

[slonomo]

I had heard about those parts being available, I've just never come across them. Good post!

[KRAZYMATT]

Ordered the 1.5 gph needle n seat. It shows already shipped and being delivered Monday! Hope that does the trick. Part number says for vm28 but was told it also fits vm30-44. Mikuni part # VM28/511-1.5

[KRAZYMATT]

Got the new 1.5 lb needle n seat and installed it- THAT DID THE TRICK! The needle and seat that came in the carb was 3.3lb. Thank you. Good to know!

[raydhd]

WOW Great follow thru. Found the solution that has troubled some swaps.

[KRAZYMATT]

Originally Posted by slonomo

I had heard about those parts being available, I've just never come across them. Good post!

I got the needle n seat from niche cycles. They sell genuine mikuni parts. I bought the rubber sleeve/carb adapter, & choke cable adapter from them prior to this. They ship fast!