Thanks for reply, Mmmm wonder weather to fit it or not now, i tryed looking for rep stacks etc but kinda hard to come by what kinda jetting you having to run with open box ?

i mean ive done basic mods like drilling slides out and shims etc, did you buy a modified brakcet or you drill etc yourself ?

eamer1989 wrote:Thanks for reply, Mmmm wonder weather to fit it or not now, i tryed looking for rep stacks etc but kinda hard to come by what kinda jetting you having to run with open box ?

i mean ive done basic mods like drilling slides out and shims etc, did you buy a modified brakcet or you drill etc yourself ?

I've seen 5 sets of velocity stacks for sale in 5 years (in Japan and UK), yes difficult to get hold of! My bro tried to reproduce some in fibreglass (and carbon fiber - they looked great!) but intricate, mounting options are limited and in the end deemed too difficult. The bike in the pic was brought like that, but have modded other carb brackets the same, dirty work with a grinder and not the easiest shape to drill in some spots.

To run an open airbox it's important to restrict the air jets in the carbs (the hrc stacks in the pic do this). You can do this in other ways like tapping the air jet to take pilot jets, which can then be drilled out to the required size (2-3mm).

If you don't restrict the air jets and just try and run without an airbox/filter you'll need to use about 160 size jets and the engine will have trouble pulling through a big midrange hole, if you restrict the air jets you'll probably end up using 140+ (depends on the air jet restriction size) jets and it will pull through the range nicely. Some dyno time will be needed if you don't use hrc stacks.

Interesting, this appears to be what the previous owner did to our NC35 trackbike as it has 160's in and does have a touch of boggyness midrange, if I wasn't selling it I'd have a play with the airjets but never mind.

Druid

There's no need to restrict the nc35 air jets, at least hrc didn't.

Do you run all of the kit carb parts? Kit emulsion tubes, springs and needles will help out the midrange.

Rite I got chance to get a bmc racing ram air system with themodified airbox lid etc what do I need to change etc to run it rite ?

Thanks Dave

eamer1989 wrote:Rite I got chance to get a bmc racing ram air system with themodified airbox lid etc what do I need to change etc to run it rite ?

Thanks Dave

This should help
http://www.400greybike.info/newforum/vi ... =23&t=1788" onclick="window.open(this.href);return false;