Tuning vm38

[geeessfore]

Since I got some time im trying to get the carb tuned right. Its ran good on these settings but its slightly rich according to my plug. Other issue is if I quick rev I get a pop out the exhaust. My jetting is 35/230

 

[Gen1Pat]

On what circuit is the plug looking rich? Idle? Midrange? Full throttle?

 

[geeessfore]

Full. Just dropped in a 220 today but still getting a pop at quick rev. Gonna mess with air screw a bit

 

[geeessfore]

Just hard getting a starting point on these carbs since noone really posts the jets and mixture they use

 

[fknboss]

Are you getting the pop when is revving up fast or while it's on the decel? If it's when you let off the pilot needs to go up or adjust the fuel screw to richen it up.

 

[geeessfore]

Reving not decal.

 

[Gen1Pat]

does it do it before you reach WOT? Could be that your needle has to go down a notch.

 

[hobbyguy2013]

Any updates?

 

[geeessfore]

No I need to grab plugs n go make some passes

 

[hobbyguy2013]

this just mite help http://www.mikuni.com/pdf/vmmanual.pdf

 

[geeessfore]

Well I ran it all last season 35/230 but could tell it was alittle rich. I think the 220 will help me out. Then just have to dial in air^fuel

 

[hobbyguy2013]

i did learn that you should use a bleed type pilot in a 4 stoke with the vm

 

[geeessfore]

Ya I have one

 

[hobbyguy2013]

what needle are you running?

 

[geeessfore]

Idk whatever came in

 

[fknboss]

Changing needles is for a minimal fine tuning. Rarely ever needed. But there's been a few times I had to.

 

[hobbyguy2013]

yeah i had a mid range studder once had to change needle.