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Posted

so heres the update on my engine situation. im polishing both my cub cylinders and prodesign coolheads atm so all other work has came to a stand still untill im satisfied. ive been working like a mad man to remove the casting bubbles and am about 75% complete.

 

so heres what my motors at and i need advice about how i should run this engine.

421cub with a 4 mill

vf2 reeds

paul turner high revs

trinity 2 into 1 with a 35mm

shaved flywheel

dynatek cdi

and the domes were labeled 19

 

what im looking to find out, what type of fuel should i run? and what timing also should i have? i was told to set it at +6 and turn the cdi on stock curve but i wasnt sure. for the time being im stuck with a 2 into 1 untill i can afford a dual carb setup agian. any suggestions on what size carbs i should be running? for the time being though what should my current jetting be? is there even a jet big enough?

 

Posted

when i got my 421 cub from jeff at fast i had already been running a single 35pwk but when i fired up the cub it would only run on one cylinder.

so i shut it off as not to burn up a piston, ordered a carb and pingel valve from jeff at fast which instantly solved the problem

Posted
when i got my 421 cub from jeff at fast i had already been running a single 35pwk but when i fired up the cub it would only run on one cylinder.

so i shut it off as not to burn up a piston, ordered a carb and pingel valve from jeff at fast which instantly solved the problem

definately get a pingle valve and drill your gas cap for a better gravity feed,also maybe a set of oversize bowls.Did you get your lockout and welded ball situation taken care of?

Posted

I would say that your bike is being restricted greatly with that single, but im no Pro.

What is your elevation?

Have you done a compression test? If not i recommend one, so you kno what kind of compression your cylinders are pushing, also that will help these guys out so they kno what octane you should be running.

 

 

I have 19cc domes in my 4mil, with about 185psi at sea level running 110 octane

Posted

compression is going to be awefully high with 19cc domes. My 421 cub kicks 185 psi with 20cc domes. Do no even think about running less than 110. Also, a single carb and a cub should not even be in the same sentence together let alone the same bike. Most guys run dual 35s or 39s on that motor.

Posted
dont you worry about the carbs i got it covered

 

LMAO :laugh:

Posted

your concerns are no longer :).

 

Keihin 38mm PWK Air Striker Carburetor

Billet Intakes Crossover

Chariot Billet Bowls

v force 3 reeds

 

its like the intake we drool over

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