pulse adernaline 125 photo guide to main jet swap

[offtheclockuk]

hi guys, dont know if this should be here or in maintenance?
im sure a mod could move it if needs be.

just a basic photo set to show the simple points involved in changing a main jet on a mikuni vm22 carb

ive not included the pull the carb off the bike and chuck the carb back on the bike as its a bit of a no brainer once everything is disconnected,

tools used and a reference as to what the jets look like are included,

please feel free to comment, or add your own info as required.

thanks, james


fuel pipe clip by offtheclockuk, on Flickr


carb/ airbox joint by offtheclockuk, on Flickr


undo nuts securing carb by offtheclockuk, on Flickr


unscrew piston cap by offtheclockuk, on Flickr


remove piston by offtheclockuk, on Flickr


dont damage piston or needle by offtheclockuk, on Flickr


remove screws from bowl by offtheclockuk, on Flickr


remove bowl by offtheclockuk, on Flickr


secure jet body and remove jet by offtheclockuk, on Flickr


screw in larger jet by offtheclockuk, on Flickr


check for obstruction/damage before closing up by offtheclockuk, on Flickr


refit and check connections by offtheclockuk, on Flickr


tools used by offtheclockuk, on Flickr


112.5 left - 115 right by offtheclockuk, on Flickr

[superfamous]

Hi
what Main Jet size are you using?
cheers

[offtheclockuk]

Hi
what Main Jet size are you using?
cheers

At the moment 115, not had a chance to run it properly yet to see how it pulls, need to find a performance cdi really.

[superfamous]

thank you for your quick reply!
Did you already check your plug? 115 isn't too rich?

[offtheclockuk]

thank you for your quick reply!
Did you already check your plug? 115 isn't too rich?

I checked the plug right after I did the swap, not done a chop at wot yet, the bike pulls hard to the rev limit, but before the swap on the #112.5 jet, it went flat around 6k and didn't want to rev further, when you snap the throttle open then shut again, there's a flash of bright blue flame, that's meant to indicate complete burn so mix must be close to right.

[relentless addict]

hey man me and u have the same carb im looking changing the jet myself where can i get one and how can i find out what size i need
cheers
guy

[offtheclockuk]

hey man me and u have the same carb im looking changing the jet myself where can i get one and how can i find out what size i need
cheers
guy

They can be found on eBay for about £3, just search mikuni vm22 jet, as for size 97.5 was the standard jet in mine, but it's not as straight forward as pick a number, you probably need to try 2 or 3, starting at 100-105 then going up if it's not enough.

[relentless addict]

kool ive gt a race cdi and full custom stainless steel exhaust system also making a custom ram air filter for it so may need a fair bit of fuel going in what u think if i go straight to 105 then higher if i need?

[offtheclockuk]

I'm up as far as 115, just trying each one for a few days till I'm happy, with all that you have done to yours 105 may not be enough!

Out of interest do you know where your cdi came from as I'm looking at getting one, there is a slight miss at high revs and full throttle, also is the cdi just a rev limit raise or does it increase power/timing etc?

Thanks, james

[relentless addict]

jsut to let you know i actually have a superbyke RSR 125 same engine as yours so same general tuning i have a kamakazi cdi gives me a power band over 8 thousand revs only problem is 3rd 4th n 5th i have trouble geting over 8 thousand revs so more air/fule is needed if u can find a kamakazi one ace but there hard to get also bigger spark