Hitchcocks Forum

Hi guys after a lot of time spent in the shed and at the machine shops I have my 350 Bullett running really well. My bike is running 500 fly wheels, Boyer Electronic Ignition a hitchcocks high comp piston and has had the head ported and bigger valves installed. My initial plan was to run a VM28 Micarb as I have also had the intake from a 500 head grafted onto my 350 head. After playing around with jetting and slides I was unable to get the bike to run well with this set up so I cobbled together a manifold/gasket that would allow me to run the Paco VM24 that my bike was exported with.

The bike runs well but has flat spots and after doing multiple plug chops and playing with jets and needle position I am either getting Very Rich or Very Lean. I want to get the bike on a dyno for a good controlled tune but would like to turn up with a quality carby that will do the job. My preference would be Round slide Mikuni but only because they have been on just about every bike I have owned. Would like to hear from you guys with any suggestions.

Cheers in advance.

65, you don't make any mention of changing the throttle slide. The jetting and needle positions are really fine tuning aids, the coarse ones are carb size and throttle cutaway in that order. I suggest you try a different slide then adjust the other possibilities. Some parts are available from our Hosts (in the Accessory Catalogue) which may help but apart from that I'm not sure where Mikuni bits could be got? It would help if you gave an idea of the settings you've used so far and the results... REgards, Mark

Throttle cutaway only effects small throttle openings but can eliminate annoying flat spots. Larger cutaway = leaner mixture.
Have you checked the float height? It's something that is often missed.

Gav,
Try the 28mm Micarb on it now that the high comp piston is in, see how that goes and as I said I don't need a dyno printout to know how bad the performance is, save your money so we can work on longstroking it

Intrigued to know how it goes with 500 flywheels, relaxed, plenty of torque and a slow tickover?