A Bit Up The Creek With Delly 28mm

[rog60]

I've fitted a Dellorto PHBH 28mm carb and MB mainifold to my Casa 210 kit and am struugling with the jetting........

Thought I knew enough etc to do the job but..............

Running through remote foam filter, changed throttle cable, converted to cable choke using existing choke cable and using a KBA clubman type exhaust.

Started with X13 needle (2nd clip down),122 main jet, AV266 atomiser, 52 idle, 40 slide, mixture screw 11/2 turns out. Plug a sooty black but dry

Engine starts easily and revs to about half throttle before 'bogging down'.....so reduced main jet to 120 still bogging down so reduced main to 118, plug still black but engine reving more freely. I have an AV264 atomiser and an X2 needle. Should I change either of these to try and lean the mixture off or am I really too low on main jet already. OR do I have another problem in that I suspect the choke plunger may be slightly raised causing a rich mix (the choke cable has sufficient slack to appear to 'off'.

Also just done about 50 miles to over 5 litres

Any suggestions appreciated

[eibargum]

rog60, its not exactly the same as yours but close enough to be of use, Muggy 210 [60mm crank used to get the 210cc] clubman, 28mm phbh & MB manifold, this was dyno,d, 14.6bhp - main 112, needle X13 p1.5, atomiser AV266, pilot55, slide 45, it was a 40 slide but i took .5mm off the cutout. Before it was dyno,d i try,d a 118 main and it ran shite, 60miles to a tank. If i were you i,d start with a 115 main and X13 p2 and come down if need,d, I did 1,000s of miles on this setup without problems, in fact its still going strong with a 58mm crank in .

[RinB]

What about trying

AV264 X13 and up main to 122 ish

[mikeallen]

I am running the 28PHBH on a Rapido 200, remote filter, 42mm AF Clubman:

AV264 Atomiser
X13 needle at 2nd clip from top
50 pilot
40 slide
115 main (may go down to 112)
Mixture screw approx 2 turns out

Hope the above is some help to you

[rog60]

Thanks guys. Loads of stuff here to try out over the next few days. I'll have to get some main jets below 118, have got 105 but that'll be TOO weak and acouple of pilot jets below 52.

[Daggs]

First job. Ensure the choke is seating correctly.
Then address the half-throttle issue by altering needle/clip position and if necessary the atomiser. The main jet has more influence after half-throttle.

[rog60]

Checked choke seating today.......OK
Can only weaken the mix via needle by dropping one clip, which is all I have left as I'm on the 2nd clip down at the moment............
Looking to weaken mix by changing to weaker needle X2 OR change to weaker atomiser AV264.

I'll post results when I've achieved a reasonable mix (judged by plug colour)

[Daggs]

All good, but judge it on splutter or not at mid-throttle, rather than plug colour.

[Dimitrios_231]

I am running the 30PHBH on a Rapido 225,Tino's remote filter, Sito Ancillotti:

AV264 Atomiser
X13 needle at 2nd clip from top
53 pilot
40 slide
120 main
Mixture screw approx 2 turns out.

Main is a little rich,but I preffer it this way.

[rog60]

[quote="Dimitrios_231"]I am running the 30PHBH on a Rapido 225,Tino's remote filter, Sito Ancillotti:

AV264 Atomiser
X13 needle at 2nd clip from top
53 pilot
40 slide
120 main
Mixture screw approx 2 turns out.

Main is a little rich,but I preffer it this way.[/quote

Thanks,
That's so close to mine, just change the atomiser.........got to try it :bouncing: :bouncing: