Jetting SF2 new Dellorto's

[Krausy]

Evening all , hoping someone could give me a base setting on jetting for new type 36mm phf's ( rubber inlet tubes ) I've fitted to my rebuilt SF2 , been a challenge.
I have it running better but not satisfied still annoyingly hunting around 2,500 to 3000 rpm and showing rich plugs on 140 mains , 60 pilots , 265 atomisers , K2 needles middle setting , 50/2 slides , balanced , chokes balanced and closing properly . Motor new so good compression .

 

[MarnixSFC]

I’d go for 50 pilots.

Marnix

 

[piranha-bro2]

Agree with Marnix - give the 50s the go. And tune your idle mixture a tiny bit richer (1/8th turn) than where you get highest idle.

 

[Krausy]

Thanks for tip gents 50 pilots definitely made a difference , idle mixture wants 2 plus turns for sweet spot so it is rich on idle.

 

[MarnixSFC]

2 turns open sounds about right.

Marnix

 

[Laverda SF]

I use to carry a pocket full of main jets for my Dellorto's. Lots depends on the Exhaust System, Air breathers or Velocity stacks (Neither preferred for me - I liked straight Open Mouth). Ensure that stupid Hose Crossover intake manifold isn't leaking or collapsing. If you can't maintain full throttle in 5th under load and it's licking you are sure to hole a piston. Put in a bigger Main Jet (Only takes 5 minutes on a road side) - Best to run a SF rich rather then lean.

 

[peerfleuren]

Main jetting is only determing mixture @ Full throttle I think?

 

[Rob]

Main jetting is only determing mixture @ Full throttle I think?

Correct. Or, more accurately, three quarters full throttle to full throttle

 

[Tippie]

I run 45 pilots, around one and three quarters turns out on the screws, you could give them a go.