125-200cc Increasing bottom end grunt/165 kit

Hey everyone, so i'd like some more grunt on my 125. I've read that the 165 really increases the bottom end power, but i'm guessing its going to be really pricey. I was just wondering if anyone can point me into the direction where i can price and enquire about the kit's?

In case that is too pricey, what mods can be done to increase the bottom end torque?

Cheers,
~ELias

speak to wallybean he does the 165 kits, i have one on mine & its transformed the bike, a cheap place to start would be to put a flywheel weight on it this will spread the low down power out depending on what sort of riding you are doing

Yeah i have spoken to him about it. Did the fly wheel weight kill your top end? And what weight wheel would you recommend?

Yeah, i've yet to use it yet (need to put the larger chain on, as the stock chain is too short) and i think it's a 54... Just hope the top speed hasn't been destroyed.

A lot depends on what type of riding you are doing, I tend to do a lot of tight shitty trails with lots of rocks & hill climbs My bike started life as a cr125 but was converted to wr spec by the NZ distributor from new so im not sure what weight it is but it wont kill your top end, i have a 52 rear and kept the std cr front, if you go to wr speck it tends to be very low due to the 19"rear wheel (WR's have 18" rear).

Jus buy a 12t front sprocket then no new chain needed

safe up and go for the 165kit and moded exhaust

safe a bit more money and get a lectron on top of that

when considering you will ride this for the next 3 a 4 years or longer its not that much and for the smiles it gives you its cheap

I have a SM 165 and a WR 165 and tuned differently by gearing and for a purpose

the SM is a full out hooligan bike in town (as intended) the WR is a mountain goat

Robert-Jan

The Lectron alone will clean up the bottom quite a bit, G2 throttle helps too, 165 kit with pipe is still the killa' I run all the above and pull 13:49 gears easily

I run wr165 with lectron ,fmf 200 pipe and silencer,12/50 gears will still do 50mph and in 1 gear without gas just idling will not quit. Great tight single track weapon. Leave bike a gear higher than you think you should most of times and let bottom end just pull you through corners. Amazing bottom end grunt for small bore.

Hi, I am based in the uk and I am looking to buy a 165kit for my 2009 Wr 125 where can I get one please?
Thanks Steve

PM wallybean on this forum

Robert-Jan

Hey everyone the 53 rear sprocket worked a treat. Yet to go somewhere wide open to see if i can max it out. But i'll leave it at the fact that i almost flipped it 4 times. Next is to buy an FMF and find a 144 kit from somewhere, but i would love to hear people's thoughts on the 144's vs 125's.

I didn't ride mine as a 125, it came as a 144, so can't compare. I have ridden stock yz125 vs yz144 with modded pipe, carb, gears and that was a dramatic difference.
I really liked my wr144, but I did add a Lectron as soon as I got it and I'm sure that made a difference. It was mostly worn out, but still pulled well off the bottom into a strong mid range and was a blast to ride.
From my memory of 125s, I don't want one except to maybe twist it's tail on an MX track, but a 150 is a great small off road bike.
With the Lectron I tried a bunch of pipes and preferred the stock pipe with FMF TC2. Without the Lectron an FMF Gnarly may be better. With the 165 kit, Lectron, G2 throttle Walt's modded 200sx pipe is a must.
A cheap mod that should help is to adjust PV valve and springs. Walt sells a kit with 3 different set of springs. I went for more top, sooner, but you can also install springs to cause the PV to open later, so more linear power.
Also a thinner base gasket may add a little more grunt, but will cost you on top.