Hitchcocks Forum

Having problems with carb on my 1961 re 350 bullet engine was running lean so I put on choke a bit next time I then increased main jet from 180 to 200 took it out same problems with choke partly on Where would I get wear on carb is it possibly choked vents can I measure any parts to carb is a 626 amal concentric any help appreciated

Hi Purple, I can see a couple of problems with your attempts to fix your problems.

1. "Putting the choke on a bit" - when the choke is off it is lifted right to the top so it is still covered bt the slide at full throttle so "Putting the choke on a bit" will have no effect at all until you've opened the throttle enough for it to show - so no effect at all at low/mid throttle openings. Obviously this is a bit of a guess since I don't know what a "bit" is.

2. Changing your main jet will only effect when the throttle is more that 3/4 open - ie nearly flat out.

Pilot jet and neddle will probably be more usefull to you.

This is all said assuming that you've no air leaks in the induction and all else is well like float hight, no blocked jets in the idle system, fuel flow OK, no blocked filters etc etc. Tech notes should help.

Set up the idle first and don't just assume that 1.5 turns out is the right setting - it's only a starting point.

Good luck, Paul.

Hi paulk
I lifted the needle a notch screwed the pilot jet in half a turn renewed the gasket checked the flange took the bike out after about half a street lenghth had to remove choke and bike went Iam going to try this on my matchless as Ihad similar problems thanks for your help
purplefox

Glad things seem better but just turning the air screw half a turn does seem a bit random. I would get the motor fully warm then turn the air screw in or out untill you have the quickest tickover then drop it down with the throttle stop - then do it again. Having to take the choke off too soon can (I emphasise can) imply a rich setting but they'll all different/ambient temp etc - have you read the tuning notes in the tech section? Then again it could of been an air leak all the time. Happy fiddling.

Mr Purple, you changed 3 variables at the same time. This is a cardinal sin. Only ever adjust one item at a time and then check the change. Always adjust with a warm engine, and always in the precise sequence set out by AMAL. I am assuming AMAL as you say you intend to do the same mods on a Matchless. Unless you proceed in single stages and measure the change each time you may never ever find out what was wrong or how you cured it. HTH.