Scooterotica

Is anyone running an RB 250 with a Dellorto 34mm fitted.
I have jetted it as per AF's spec sheet but it is really boggy up to 1/2 throttle.
Setings are
K21 needle
DP267 atomiser
Main 198 ( but have not actually got to this so far)
Pilot 55
Choke 60

Have tried a DQ266, it is slightly better, but still very boggy.

The gearing is SX200 with 16x46 sprockets ( 4.5)
Exhaust is franspeed tourer.

Due to runnig it in I cant go above 55 mph for a while, and with the gearing the throttle is only about 1/3 open.
Any help would be appreciated

I agree that you should not have hit the main jet circuit yet, but that main jet seems huge. Why not just try a 160 just to see.

What have you got to lose for the sake of a quick blatt up the road.

Also, check that the choke is closing properly, as it might be open all the time. Have a look down the mouth of the carb and you should be able to see the plunger.

Finally, have you adjusted the air screw?

Why not fit the 15x46 while you run it in, then switch back later......Got to agree with Knowledge the main jet does seem big...

The main is what is recomended by AF.
I thought it maight have been the choke, so disconected it, but it was still the same.
I dont think that there are many about a the moment, if a few people have them you can compare jetting and generally get it a bit nearer.
Might go down the Mikuni route, had one last year on my RB225 and it was fantastic.

hi my rb25 runs
40-slide
k24-needle 2nd clip
dp267-atomiser
195-main jet
45-pilot
60-choke
300-float valve
gp 200 gears/19-46 sprockets
varitronic 25 degrees initial advance
runs clean thru all the gears
hope this helps

I think I have sorted it now. It was probably a combination of thgings.
I cut and remade the choke cable so that I am sure it isnt open when running.
There is an inlet on the side othe carb, which I think is for an oil injection, this wasn't blocked, it is now, have dropped the pilot to 45.
I now need to try a DQ267 atomiser as I have a DQ266 on it at the moment and I think that it will be lean in the mid range.
Thanks for posting your findings
I think I maight change the gear ratio aswell, it pulls 4.5 but it struggles a bit if I am not revving it up hill

How are you getting on with this?

I've the same set initial set up as you and boggy as f@@k up to half. After that it's too lean.

Struggling to find an answer