03 RM125 Torque/Bottom End Mods

Cometic high performance top end gasket kit has a thinner base gasket
Try some VP ultimate 2
I don't think FMF makes gnarly pipes for 125's
Dyno port might make a torque pipe, "big volume"
Try adding spacers to the pipe, between cyl and pipe
Shorten the silencer
Torque reeds
Reed block spacer "should" help

No fmf does not make a gnarly for 125's. After upping the rear sprocket you might try differents reeds or a complete V force set up

Chilli- what you are wanting, is like asking a beautiful brunette to bleach her hair blonde!:)

for the sprokets, dont go too mad- ive tried it and it can make the bike real gutless- it just goes nowhere fast with the big back sproket.

as for v-force, steer clear the low end jetting will be so off you arsking for trouble. i am not sure reeds and spacers will help much- the stock settup and carb sounds good- Dean, Steve????

do you have good fuel? the stock base gasket is 0.5mm thick- you can run the cometic high comp kit- here the base is 0.3mm dropping the ports a bit and the extra comp should bump the low end throttle response a bit.

as for pipes, my 144 is on stock port timing so it should be similar, the fatty has more bottom than stock, but falls off a lot quicker than the stock on top. you can even add a few spacers to the front section of the pipe like ochster did on the SX bike- you know the little washer- 2-4 should help. you could also shorten the silencer a tad or even the fmf shorty, marcus D'ned the pipes so we will wait for his comments.

does the 03 have that PV adjuster spring??? i think messing with that can be trouble if you dont have a dyno though.

at the end of the day, i wouldnt go too far looking for low end since you will lose the best part of the motor- keep nagging the lads about that clutch, if they are racing i am sure they will get fed up with getting left in the corners and start using it- in 6 months you see him jerking the bike through the pits, you know its time for a billet basket and your work is done! :worship:

The bills pipe is good for the rms, dont think much to the v force-going to test a boyesen 3 rad valve soon on the 04-be careful increasing compression on the 03 as its high already, good jetting as the 03 comes very rich.

try backing out the pv adjuster half a turn and see if it pulls better-they appear to be too tight from new.

marcusgunby said:

try backing out the pv adjuster half a turn and see if it pulls better-they appear to be too tight from new.

Click to expand...

thats quite a lot actually mate- the PV spring has about half a turn of preload as stock- i think this setup needs only small adjustments- Deanfasty knows a bit more i think and i bet he knows about them reed spacers, Dean??????

Chilli:

i understand on the fuel, believe me i do! when i was a pro-practice rider, i ran straight C12- now i am racing, i have to mix it 50:50- ironic really!

on the next topend, take some measurements on the squish etc and see where we are- a small head mod along with that thinner gasket could help a bit.

talking of RMs, Travis just posted 3rd fastest time in practise at Daytona! :yeehaw:

bruce half a turn-well thats very different to the 250 guess i need to not assume so much? well then i would say only a eigth of a tun less then? you can always go back to std.

On the reed spacer-some bikes like it-it will make getting the carb back on hard and the boot may rub on the shock spring.

The 04 cr250 benifits from a huge reed spacer-something like 10mm. However it doesnt like the exhaust spacer(manifold) from the 03 cr250-you have to just try these things really.

its all coming back to be now- marcus makes good points, there is a bit of room though- my carb is about 12-15mm longer than stock and it just touches the spring, so with a 10mm spacer you should be OK.

now, as for the spacer, thats easy- the RM uses the same manifold bolt pattern as the yz125. there is a guy selling the reed spacers for the yz cheap on ebay