Hitchcocks Forum

Does anybody have any starting advice on what main jet to fit in a 32mm Concentric on a 535 Bullet using the Accralite piston

Main jet 220 - possibly 240.

Norm
My 535 Accralite piston and 32mm Mk2 (and Mr.H’s performance cams set to match Ace Café specs, Ace Café air cleaner, twin plugged etc) needed a 2.5 slide to eliminate a dead spot at half throttle and as a result I am dead happy with a 105 needle jet (clip at #3) and still testingh between 220-230 main jet. With the standard #3 slide, I started at 106 needle at position #3 and a main of 240 and the ¾ throttle plug chops were not too lean (tried it also with jets from 220-260 and needles from 105-107 with little evident change on plug chops - perhaps due to our high ethanol petrol).
With that (2.5 slide) setting it was OK for a GPS 115kph at exactly half throttle (measured at the slide) on a flat road with no wind. Didn’t test higher because I don’t trust the steering (bit of a wander at speed to be fixed) but there was lots more to come. Haven’t got any further with testing as I am still repairing the damage ensuing from the broken circlip (yes, it was new when installed some 2000km ago).
ChrisD

Welcome back Norm!

Norm, Tom Lyons (ACE products USA) wrote a detailed piece on fitting the 535 kit with forged piston. You can probably find it by searching the Message Board but if not I kept a copy. He has some very important things to say about adding compression plates and ring gaps and re-setting ignition advance. You may well know what he has to say but just in case I recommend you read it!

REgards, Mark

Thanks everyone, gives me something to work with

Ok so I will see if anybody has any guesses on this one. Model G fitted with a 22mm Amal with a 140 main, does this sound about right. This motor was fitted with an A65 high comp piston and whilst I was riding beside it , big puff of smoke and a holed piston. I'm pretty sure he was running wide open at the time. I have now fitted a lower comp Toyota Corolla piston and I'm wondering if anybody thinks this main jet would be about right, big guess I know

Hi Norm - try a 160, or 170 main jet for starters, should be somewhere near. Cheers,
Paul.

Thanks Paul, I'll give that a try, it is a 24mm carby not a 22mm, my bad.

And Paul while I have your attention, is there any way to stop this motor without pulling the plug wire off, there appears to be no way of earthing this mag out