Blackjack Tuning help

[flyin Hawaiian]

I’ll try and make this short. I recently finish re-building my motor. Setup is ada head with 180psi, surf port by Paul at lehr, lightened flywheel, msd enhancer and a Factory TNT chamber and a 44mm Blackjack carb.

Well I have read the Mikuni book a zillion times and think I understand what I’m doing but am having a problem getting this thing tuned during break in. I’ve spoke with Art at Jetworks a bunch of times but still can’t figure this thing out.

I am currently running a 155 main, 130 pilot, 2.5 needle and seat with an 80gram spring.
To achieve the best idle the low speed screw has to be set at about half a turn. I have read that if you are less than a turn out you should go down a jet size. With the ski set like this at ¼ throttle if I grab it the ski will hesitate. If I open the low speed screw it starts to clear up. Dose this make sense?

On the other hand when cruising at ¼ or a bit more the ski will surge a little so I tried squirting a bit of gas with my primer and the ski would want to die from flooding.

IM SOOOO CONFUSED……… HELP

 

[crammit442]

I’ll try and make this short. I recently finish re-building my motor. Setup is ada head with 180psi, surf port by Paul at lehr, lightened flywheel, msd enhancer and a Factory TNT chamber and a 44mm Blackjack carb.

Well I have read the Mikuni book a zillion times and think I understand what I’m doing but am having a problem getting this thing tuned during break in. I’ve spoke with Art at Jetworks a bunch of times but still can’t figure this thing out.

I am currently running a 155 main, 130 pilot, 2.5 needle and seat with an 80gram spring.
To achieve the best idle the low speed screw has to be set at about half a turn. I have read that if you are less than a turn out you should go down a jet size. With the ski set like this at ¼ throttle if I grab it the ski will hesitate. If I open the low speed screw it starts to clear up. Dose this make sense?

On the other hand when cruising at ¼ or a bit more the ski will surge a little so I tried squirting a bit of gas with my primer and the ski would want to die from flooding.

IM SOOOO CONFUSED……… HELP

N/S seems a bit big. I'd run 2.0 or 2.3 w/80 g spring. If opening the screw makes it run better, open the screw. The manual is a good basic starting point, but don't hesitate to use the screws to actually tune. If you find that opening the screw fixes the problem but runs rich farther up the power band, go down a jet or up a spring. Stick with what Art tells you. He's the MAN!!!:veryhappy:

 

[flyin Hawaiian]

N/S seems a bit big. I'd run 2.0 or 2.3 w/80 g spring. If opening the screw makes it run better, open the screw. The manual is a good basic starting point, but don't hesitate to use the screws to actually tune. If you find that opening the screw fixes the problem but runs rich farther up the power band, go down a jet or up a spring. Stick with what Art tells you. He's the MAN!!!:veryhappy:

Thanks for the reply. Opening the ajuster makes it run better off idle but the idle is then very rough.
I here these are the only carbs you run. What is your set up and carb specs?

Thanks