KR-1S.co.uk Forum

I have a set of boyesen dual stage reeds [not sure what to do with them]

has anyone used them. are they any good,

Yes ive used them,
They required the mixture altering to work well,provided a bit more driveability "off the pipe" which was handy as the engine was/is highly tuned for mid to top power.
Worth a shot for a road bike,but dont expect massive gains.
Pretty sure they dont work as intended with stock stops,should have come with the rev plates,if not quite easy to make them,they just cover the lower edge.

thanks dave. I may try them out.
they did,nt have the thinmetal plate on the bottom of the bottom reeds,
surly they would be ok with the standard reed metal stop [that's how they were when I took them out of the bike I stripped

No problem
you can try them with the stock setup,it wont hurt,but they were developed to be used without them.
TBH ive tried different reed setups on my Onda RS 125 race bike and there is never a BIG difference when swapping just the petals,ive used those designed to work with or without the standard stopper (on the RS) and it is never a noticeable gain or loss,maybe this is cause it spends its time above 10,000rpm unlike a roadbike.
Fitting a V force did make a noticeable difference though,and a boyesen rad valve on my KX125 made a HUGE difference when pulling out of slow corners.
Reed changes alter the fuelling,sometimes this can be right for your engine/use sometimes not,its just something you've gotta try and then decide.
HTH
Atb
Dave

good advise as usual dave, thanks.

maybe I can cut down some original reed stops

Yes if you have some spare ones its possible,i will have a look at my boyesen rad valve thats on the bench,im pretty sure the rev plates are just are quite thin compared to the stock stopper material.
ATB

the so called "boyesen rev plates" and the HRC part for late year RS125's GP's are 1.5mm in thickness.