KR-1S.co.uk Forum

Question what difference do RD jets make? Got 137.5 mains which are marked up RD, do they equate to a different size for Keihin's? Standard KR carbs by the way. Any answers greatly appreciated.

Rd jets have been tested to flow less than keihin jets. 137.5 rd jets will flow less than keihin 135, probably nearer 132 or even 130. Is it kr1 or a kr-1s?
If you need more jets, Allens performance have genuine keihin jets for about £3 each, worth it for peace of mind- you really don't want to be running too lean.

Throw them in the bin

Thanks for the answer, its a KR1-S and they are they jets that came in the bike. Bin it is then

Your quite a bit leaner than stock with what you have at the moment.
RD142.5 flow LESS than 135 genuine (stock)
RD150's flow slightly more than a genuine 140.