Hitchcocks Forum

hi bw big thanks for the chat today and a bit of an update been out tonite for a bit of a tinker and a play in a mates field ,i adjusted the float as you said fitted 900 main jet and well i cant believe it,you are a legend just wish we spoke a couple of years ago ,will let you know how the weekend goes
thanks again steve

Hi Steve, great news and glad I could help! Don't be afraid to go bigger on the main jet if you want, you won't hurt it - our 350 racer has been up to 1500 in the past, but now uses a 1200. Have fun this weekend!
Cheers, Paul.

Sounds interesting, can the rest of us have a flavour of how going so big on the main jet helps? Is this on petrol?
REgards, Mark

Hi Mark, no black magic going on - the big jets are for running on methanol! Paul.

Hi guys--------- from my Grass-Tracking days (1970's) I seem to remember that, for approximation purposes-- Methanol fuel/air ratio is roughly twice that of petrol ?? ( ie if petrol is 15:1 approx. then Methanol is 7or8:1--or in that region).So as the air induced remains constant then the fuel must be approx. doubled in quantity to maintain the correct mixture ratios, hence the BIG sizes allied to a 10:1 compression ratio. My first and very experimental machine was the riders favourite of the day ---the BSA 250cc C15 with AMAL Mk1 Concentric. A 1/8" drill did for main jet with an induction tube of some 2.5" long made from Morris 1000 exhaust pipe and flanges cut (By chain drilling and hand filing )from 1/4" steel plate. There was a chemical stripping factory in the local Industrial Estate who supplied us lads with cheap Methanol and promised a sponsorship if we made the top grades-----alas, not to happen...I've still got my steel shoe with it's hardened bottom surface---what's the material used for that ?? BW--can you enlighten me ?? Lots of dosh spent up at ALF HAGON'S place in East London. The best I ever did was to win 1 qualifying round --- Oh well. Anyone ever heard of a chap called Bruce Carter from Tadley, Berkshire ??