Dellorto Phbh Carb On A Cota 349

[roberto]

I was wondering if there was anyone out there with some experience with these carba. I wanted to know about slide number or type, needle number and low speed, high speed, and starter jet sizes??? Thanks.

[christoff]

Hi

I put one straight off a Fantic 249 (212cc) straight onto my Mont 242. Ran a treat with no re jetting.

Maybe wort starting wit an old carb straight off a trials bike. Probably wont be too far off.

[jse]

I was wondering if there was anyone out there with some experience with these carba. I wanted to know about slide number or type, needle number and low speed, high speed, and starter jet sizes??? Thanks.

Believe it or not, I did this swap on a friends Cota and it ran quite well. The oval port PHBH26CS (air screw model, known as the "large body" Dellorto) was off a 96 GasGas 338cc (JTR370) and worked essentially with the GG jetting (at sea level).

MAIN: 115

PILOT: 45

NEEDLE: X18 (2nd CLIP POSITION DOWN FROM TOP)

SLIDE: 55

AIR SCREW: 1.5 TURNS OUT TO START

Jon

ps. Forgot to add: These carbs often work well on the early bikes due to their throat bore design, which is oval (like the early four-stroke Keihin models) rather than round. This makes them act like a smaller than 26mm carb at low slide openings and maintains a higher velocity of air over the needle jet tower promoting better atomization of fuel and aiding the "idle circuit-to-pilot jet-to-needle jet" transition of the fuel/air mix. As for the starter jet, they often come with #60 or #70 and seem to work better with a #80 starter jet, or you can drill out the jet with a .8mm or .031" pin drill (best to do in a lathe if you have one).

Edited November 23, 2008 by JSE