Jetting question when switching from stock 26mm carbs to 28mm Keihin PWK

[Tobynblevins]

I'm  buying 28mm Keihin PWK carbs and replacing my stock 26 carbs with them.. my stock carbs call for 280 main jets 30 pilots with my pipes in the stocks . But I'm going to a 28mm keihin carb and they don't make 280 jets for those  they start at main jet #155 end at 178  question Is what would be a 280 main  jet in the keihin carburetors.. for example would a #160 keihin jet be a 280 stock carb jet  I know there different from what I read. I just want to start somewhere and working my way up because I am putting ported cylinders on my banshee that's bored 1 over with vitos piston. Not sure what port is on this cylinder 

[Tobynblevins]

Anyone 

[trickedcarbine]

Mikuni and Keihin carbs are totally different Jets.  There are some charts out there that show a corresponding jet from Mikuni to Keihin. However it will probably only get you in the ball park as there are other variables. So going up in carb size changes the pulse signal at the bell of the carb so that changes jetting. Then I believe you mentioned you have some sort of porting on your cylinders, that’ll mean more fuel as well even if you keep your stock carbs. Those jet numbers from DMC are for an otherwise stock machine, so if you have pod filters and some kind of porting those jets will leave your machine wanting more fuel. Not enough fuel melts pistons and then some. 

[trickedcarbine]

This would probably be worth a look. It’s basically a whole bunch of different set ups with sorted out jetting figures. So take a look and see where guys with your same set up have ended up. 

 

[Tobynblevins]

14 hours ago, trickedcarbine said:

This would probably be worth a look. It’s basically a whole bunch of different set ups with sorted out jetting figures. So take a look and see where guys with your same set up have ended up. 

 

I was not able to find any one using 28mm carbs.. but it's good to check out ty