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Has anyone fitted a mikuni to a 612 bullet?
Posted: Sun Nov 15, 2020 10:03 am
by stinkwheel
I'm getting increasingly fed up with the idiosyncracies of the Amal concentric on this bike and I'm just about ready to hoy it in the naughty corner and fit a mikuni.
Trouble is setup, where do you start? Not even sure which one. A VM32 would seem to make sense but equally, the guy who does the ACE fireball kits uses a TM32 flatslide.
If I can find out a rough start point, the rest can be tweaked but at the moment I'm not even sure where to start with regard to slide, needle profile, and jet sizes.
Re: Has anyone fitted a mikuni to a 612 bullet?
Posted: Sun Nov 15, 2020 11:13 am
by mart
No, but I have bought Mikunis for other bikes from Allens Performance and they will supply a carb with base settings, based on your engine type. very helpfull chaps.
Re: Has anyone fitted a mikuni to a 612 bullet?
Posted: Sun Nov 15, 2020 11:32 am
by stinkwheel
mart wrote: ↑Sun Nov 15, 2020 11:13 am
No, but I have bought Mikunis for other bikes from Allens Performance and they will supply a carb with base settings, based on your engine type. very helpfull chaps.
Cheers, yes, they were going to be my go-to in the absence of any more specific advice.
Re: Has anyone fitted a mikuni to a 612 bullet?
Posted: Sun Nov 15, 2020 12:31 pm
by mart
they supplied a Mikuni for my '66 Triumph TR6R and it ran perfectly out of the box.
Re: Has anyone fitted a mikuni to a 612 bullet?
Posted: Sun Nov 15, 2020 2:06 pm
by Adrian
Bullet Whisperer is our champion Amal tweaker, though he might steer you in the direction of a Mk2 Concentric.
That said I had a VM32 from Allens' years ago jetted for a 350 Goldstar, it worked superbly on my tuned BSA B40. Our hosts sell Mikunis too, of course.
Meanwhile I reckon a PHF36 Dell'Orto would do a splendid job on a 612. Think outside the box, guys...
A.
Re: Has anyone fitted a mikuni to a 612 bullet?
Posted: Sun Nov 15, 2020 2:51 pm
by stinkwheel
I'm working on the principal that the mikuni VM series are known to work so well on bullets, people don't notice they are there and so replace them with amals so they can have something to constantly fiddle with.
Outside the box would be a Wahl-Phillips.
Re: Has anyone fitted a mikuni to a 612 bullet?
Posted: Sun Nov 15, 2020 3:19 pm
by Adrian
If you haven't already seen this, here's the thread off the US forum with various successful carb settings, from a mix of TM and VM Mikuni users. Can't remember if there are any 612 owners among them.
https://forum.classicmotorworks.com/ind ... ic=16053.0
A.
Re: Has anyone fitted a mikuni to a 612 bullet?
Posted: Sun Nov 15, 2020 3:38 pm
by stinkwheel
Cheers, bookmarked that one!
Re: Has anyone fitted a mikuni to a 612 bullet?
Posted: Sun Nov 15, 2020 9:38 pm
by Bullet Whisperer
The 612 Engine I built for 'Slo Poke' for Count Johnny, initially ran with an Amal MK 1, then MK 2 [in order to have a larger size] and finally, a Mikuni. I am not sure why this last change was made and it wasn't done by me, but I have ridden this machine with all three carbs fitted at different times and it ran pretty well on all of them. Perhaps C.J. will see this and offer his opinions and reasons.
Re: Has anyone fitted a mikuni to a 612 bullet?
Posted: Mon Nov 16, 2020 9:09 am
by Presto
Surely it is the case that an engine with the correct size carb jetted correctly for that engine will run equally well whatever name or make or type number is stamped on the size of the carb. All that matters is size and jetting. Which is why I do not understand the constant whinging against the Concentric Mk1. Set-up correctly for the engine it is fitted to – especially one as basic as a Bullet engine – it will run as well as any other carb – and does.