Vforce 4 jetting

[maggdog]

I got a new v force 4 reeds,

 

Fmf golden series and powercore2, stock carbs (280 mains), stock pilots(25), stock airbox with lid (not snorkel), stock needle middle position, 1/2 turns on air screw

 

need to rejet some, mains? pilots? or keep setup

[Strm Trpr]

Word around the campfire is VF4's like a fat pilot.

 

I'd go to a 27.5 pilot, needles 4th groove from blunt end, and 300 mains.

 

If you're currently 1/2 turn out on your airscrews, you should be running 27.5 pilots.

 

Put the VF4's in with 1/2 a turn on the airscrews and 27.5 pilots and see if you can lean it out to at least 1 turn out and not have an off idle lean bog when you crack the throttle open.

 

If the carbs want 1/2 a turn or less step up to 30 pilots.

[Strm Trpr]

If you do go to 30's, set your airscrews to 2 turns out, needle clip middle groove and 300 mains.

Adjust airscrews to get a crisp off idle snap and do a proper plug chop to verify main jetting isn't too rich.

 

Of course non of this matters if your air filter isn't clean, carbs aren't sync'd.

With your finger, put some motor oil on your new reed gaskets to soften them up.

 

Use blue loctite on the reed cage screws and never use really sticky sealant that requires scraping or wire wheeling the shit off of soft aluminum like the reed cage sealing surfaces.

 

Ultimately you should also do a leakdown test to guarantee you do not have any air intake leaks.

[maggdog]

Word around the campfire is VF4's like a fat pilot.

 

I'd go to a 27.5 pilot, needles 4th groove from blunt end, and 300 mains.

 

If you're currently 1/2 turn out on your airscrews, you should be running 27.5 pilots.

 

Put the VF4's in with 1/2 a turn on the airscrews and 27.5 pilots and see if you can lean it out to at least 1 turn out and not have an off idle lean bog when you crack the throttle open.

 

If the carbs want 1/2 a turn or less step up to 30 pilots.

clarified, the airscrew is "1 1/2" turn out not 1/2, sorry

[maggdog]

but i got the idea thanks

[trickedcarbine]

30 pilot

Second from bottom needle clip

290/300 main

[Mrtaterman]

had fmf sst pipes, and vf4 reeds. 27.5 pilot and 300 main. 

now i have a lot more done to it

[maggdog]

i'm confused, with this pic maybe i understand

 

i know is a keihin chart but, is a correct number of needle position is same on mikuni?

[trickedcarbine]

Yes same adjustment principal applies, however the actual alpha/numerical identification marks will not be the same.

[maggdog]

Yes same adjustment principal applies, however the actual alpha/numerical identification marks will not be the same.

Only need the positions, nevermind alpha/num but thanks for the info also

[bigweav81]

It's common sense sir. Look at it, and ask yourself what lowering the needle vs raising the needle does.

 

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[edgehanger]

Why so big on the mains with the lid on? Are the golden series that much different from the sst and fatty? Is it the vf4's? Got some port work? 300 main sounds rich to me on a stock bike with the lid on

 

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[Strm Trpr]

^^^ very rich!!