Rejetting of carbs

[nachtjaeger13]

Does anyone have either experience or knowledge of the size of jets the VTR carbs would need when fitting an aftermarket exhaust system and high flow air filter?.

[tony.mon]

Oh, dear.
I wonder if he'll want to know what pressure his tyres should be next?

Who want to start the argument this time round?
I can't be bothered.

[Stephan]

48 pilots, and I would buy 180, 182 and 185 jet, bigger is probably not needed.

Start with 2 turns out on front and 2.25 on pilot screws, 178f 180r jets, rear needle shimmed by 0.5mm. This should give you good baseline, you can try go one or two sizes up on mains then.

Other things you can change is to shim the needles by 0.5mm (leaving rear 0.5 more), and 2.25 2.5 turns out.

Leave stock springs and holes.

[jchesshyre]

Rear needle possibly doesn't need an extra shim if using stock needles, since the stock setup already has a slightly richer needle in the rear carb (assuming they're installed the right way round...).

Also, there are a tonne of threads on here and on the US site about carb set-up. Because of their size these are tricky carbs to get right especially when the intake tract is modified from stock, and don't always behave how you'd expect. If you don't have easy and repeated access to a dyno (or even if you do!) you could be in for a long journey to getting it right. Hopefully you're ready to get well practised at taking the carbs off and putting them back on again!

[fabiostar]

standard honda filter, standard honda jets, any exhaust you want, hit the starter and ride of into the distance and smile