Scooterotica

Hi all, i have just fitted a BGM 30mm powerjet ( blanked ) carb on my Imola engined scoot, and it is a great improvement over the 28mm Mikuni it's replaced. It has really improved the acceleration and low down grunt, but it is bogging down once past 3/4 throttle. Has anyone fitted this carb to an Imola that could give me some advice / tips, as to the correct set up? I'm running the engine on 16 / 47 sprockets, Ducati light flywheel and JL / Franspeed 3 pipe. The cylinder has been quite heavily tuned and is in the low 20's BHP wise. I know jetting is different on every engine, even with exactly the same set ups. I'm just looking at getting it in the right ball park, before i book a dyno session somewhere. Cheers all Pete.

MB should be able to help,they sell the bgm carbs.

@10 inch Terror: good to hear that you like the neat PWK carb.

these are some proven setups for the PWK range:

For the Lambretta the JJK needle should be fine for a start. JJL and JJM are used as well on setups on the Lambretta.

The pilot seems to be between 45-50.

130-140 seems fine for Stage4 , Honda205 and Rapidos with a expansion chamber.

140-155 seems to be used on TS1 setups.

Some proved Setups are:

· Mugello 200, Clubman: 125 main, 45 pilot, JJM needle
· Honda 205, Taffspeed Road, no filter, 28 mm carb: main 130, pilot 50, JJK needle (2nd clip from top)
· Rapido 225, JL3, 28 mm carb: 140 main, 45 pilot, JJK needle (2nd from top)
· dl 200 all original: PWK24, standard setup, only main jet changed

Cheers Philipp

Hi Philipp,
I did buy the carb from you, could you please tell me how these carbs come set up from you as standard? Thanks very much Peter.

Hi Peter!

Sure, they come with 140 main jet, 42 idle jet and a needle that is too rich for the use on a geared scooter.

Hope this helps!?

Cheers,

Philipp

Philipp, which needle would you suggest for a TS1 with a BGM30. I have one of the XL needle kits.

Hi Corrado!

Depends very much on the exhaust, for a start I would use the JJK. And see if you can get it rich enough to jet it down afterwards.

This is the needle chart for the bgm needle set:

Taper L1 (top groove to begin of taper) mm Diameter (above taper) mm
HKJ 2°45' 25,85 2,445
HLJ 2°45' 27,20 2,445
JJK 3°00' 25,40 2,455
JJL 3°00' 25,40 2,465
JJM 3°00' 25,40 2,475
JJN 3°00' 25,40 2,485
JJQ 3°00' 25,40 2,505
JJS 3°00' 25,40 2,525
JLJ 3°15' 27,20 2,445
KLK 3°15' 27,20 2,455

Thanks Philipp, I'll be using a JL3 exhaust.

Philip is a LJHP 3.5 needle about right? and are the power jets on these carbs worth leaving open?

@corrado: the jjk is fine for a start with the jl3 me thinks.

@gadgetman: on what setup?

the power jet does work if the engine sucks hard enough. found it working on the TS1, but on not very high revving bikes it hadn't an effect.