Hitchcocks Forum

I'm putting together a 570 Bullet, hopefully have it running on the weekend and I'm wondering if anybody has any carby setting tips. Thinking of using a 30mm PWK flat slide, or maybe the Micarb initially with big jets. Any thoughts?

I would open the ports up to 32mm , my 535cc classic engine had the valve guide humps flattened down with no problems and after many years of the rattley old Amal MK 1 I have moved on to the Amal concentric MK 2 with the adapter manifold . The first problem I found was the 50mm stud width meant I had to file some metal away so the nuts could turn and I had to remove the rear r/h fuel tank lug and 10mm off the frame lug just so the carb would fit , the MK2 has no tickler just a cold start leaver wich was not anough so I flood it with my hand over the carb for a stroke or 2 , this means the air filter has to be off for starting . My main jet size is 220 with a 45 pilot jet , I'm still tweeking my needle hight and I have a number 3 slide cutaway . there is a smooth bore version of this carb and a bought the compleat alcohol conversion kit for when I find a way if importing a distiller from the states which could make 2 gallons a day if an oil crisis rears it's head but it's a very well made carb and more practical than the Amal T3GP2 that has no tick over screw

Phil,
Headworks have already done extensive work on the head so no problems there and I have a 32mm Concentric I could try and also have 32mm flatslide and was just tossing around ideas as to what might be best. After fitting that beautifull longstroke crank I don't want to mess things up

Hi Norm,
If it helps, I tuned a 500 with a MIKUNI 28 mm carb and opened the main jet out to approx 135 and that worked ok. I put a 34mm MK II Amal on another tuned up 500 job and fitted a 270 main jet in that. I dodged the head steady / tank bracket by angling the manifold face slightly, by putting it in the lathe on the skew. I have never tried any flat slide carbs, though, so I have no info on them, but dare say you should be pretty generous with the jet sizes to begin with at least.
Regards, Paul.

Thanks Paul, big jets to start with was my plan

Hi Norm, I have run a Bullet 570 for around 4 years and in the last year with a 32mm Amal Mk1 concentric running jets sizes 106 needle, 220 main, 3 slide and top notch on the needle. In the last two weeks I have run a 230 main jet which made running at 65mph over long distances much smoother and the plug colour much to my surprise is almost a dark chocolate brown. Throttling back from high speed I noticed a slight step change in the fueling so I shall try a 2 1/2 slide. Tickover is fine so I plan to leave the needle jet at 106.

Are you building an AVL570cc? I think heard similar stuff about it but never saw any of these bikes. If that is the case then how are you getting the parts required for it?

Carl,
Thanks for that, exactly what I needed,
Dampking,
Not an AVL this one is a cast engine.The crossbred motor is going to 535 shortly, if my mate ever returns it, worried he is liking it too much