Another vm34 tuning thread

[ZayneE30]

Looking for some suggestions on what to change next.

Current setup:
Vm34
Slide #2
PJ: 17.5
Needle: 6f9 on clip 4 (1 up from bottom)
NJ: P6
MJ: 185
Mix screw: 3/4 turn out

Stock exhaust and 2 stage uni filters (red ones)

Current issue: 1/8 - 1/4 throttle from a stop is a little weak. Main problem is on the freeway at 60ish mph 4200 rpm the bike fails to hold speed. I have to go past 1/2 throttle but by then I start accelerating. I want to hold at that 60ish mph.

WOT feels strong.

It’s a set from niche cycle, came pretty lean. I went up from a 15 PJ to the 17.5, it was popping really bad on decel with the 15. I went from 175 MJ to 185 MJ. So far this is what I’ve done.

I’ve been following the Vm34-36 pdf guide that’s been sent around here and read that I should avoid setting the needle clip on position 1 or 5. That’s why I stepped up MJs to try and help 1/2 throttle. Should I get a step richer needle or needle jet? If so which would you recommend?

Thanks

 

[Wagner73]

Here are MMM's (and others) recommendations:

Mains - 190
Pilots - 25
Needles - 6F9
Needle jets - P6
Slides - 2.5 (2.0's will generally be ok as well)

You may need to go up on the PJ. And if you bump the mains, you could drop the needle as well. Then start from there.

 

[ZayneE30]

Thanks! I have some more jets on the way, the largest PJ that came with the kit was the 17.5. If i’m still having trouble I think I’ll get a 2.5 slide and follow that list closely.

 

[Wagner73]

Yes. And if you have surging in the mid range you need to raise needles. If not, and you have a stumble, you need to drop needles. @5twins has posted his mid range / main jet tutorial and I think it is good!

 

[Kevin Werner]

I have a stockish 81, pods, commandos, 1.5 headpipes that likes 180 mains, 117.5 pilots, needles at #3. Each bike is a little different. This winter I went to a 32t and a spring ride may show me I need a new tune.