BGM 30mm / Imola set up advice / tips

[10 inch Terror]

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.

[soosh]

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

[Philipp]

@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

[10 inch Terror]

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.

[Philipp]

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

[corrado]

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

[Philipp]

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

[corrado]

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

[gadgetman]

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

[Philipp]

@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.