Getting the most out of the 125

I have a 06 WR125 and after some tuning it really has all the power I need. That being said it is always fun to get a bit more. I might do a big bore but I am also interested in getting the most out of 125cc. This is mostly for fun without spending too much money. I do not want a top end screamer. Low end is nice but what really matters is that the power is smooth and linear.

Currently I have the head cut for 1mm squish, a Keihin 36mm PWK, turbine core II silencer, and timing slightly advanced. The bike pulls 200 pounds around real nicely as long as I have the jetting perfect.

Is there much room for improvement with porting only? Has anyone had eric gore port work or a FBF ported 125 cylinder? What about case mods? Is there a bad mismatch between the case and cylinder ports or gasket overlap that gets in the way?

Reviews of pipes are mixed. It looks like they helped on the older ones but I don’t know about on a 06. Someone here stated that the 07 stock pipe is real good. Does anyone know if the 06 pipe is the same as 07? Husqvarnausa seems to say the pipe changes every year but I doubt that. I need to get a spare anyway so I might experiment.

I’ve thought about trying a Rad Valve since I can get a Honda CR125 one on ebay cheap anytime I want. People with YZ125’s seem to favor them over the V-Force.

I would really like to try the CR ignition if I can find one cheap. I suspect the WR is better in the woods though so unless I see a CR being parted really cheap I probably won’t. I do think my bike would be better with a bit less fly wheel weight though. I could have the stock one lightened but that is irreversible. It seems that guys who ride 125’s in the woods either love FWW or hate it. I never stall my bike so maybe being able to get it spinning faster would be an advantage. I will probably go to the Husky demo day so if they have a CR I’ll take it for a spin and decide if I like it better.

I would really like to try a 38mm PWK but not enough to spend $200 at this time. My bike is really picky on jetting. In theory a smaller carb should be less picky but the KTM guys seem to agree that the 38mm is easier to jet then the 36, at least on a KTM. I think I lost a little top end with the 36 also. I get excellent range now though which is one reason I picked the smaller carb. Bottom end pull is also much improved over the stock carb.

Well those are the things I was thinking of experimenting with. Who has tried any of them?

Maybe you should try the CR .I have a stock 2006 CR 125 like i have stated in other posts it is stock .I do not even know what jets or where the needle is set.I did take the carb apart but my eyes must be so bad because i could not see the # on the jets.What i do know is my son use to race it and won some expert Dist 37 races and 1 National on it.This year i am racing it in the Dist 37 Desert,Enduros and AMA Nationals.I am having the best finishes ever

at the AMA Nationals i have to race against the open class bikes.After

3 National so far this year the little 125 is leading in the points expert class.

My over all finishes are better then last year on a open bike.The little bikes just works at the Nationals we have been in all types of terrian from rocks to sand dunes and even high speed sand washes where the 125 is holding it own against 450 .What else can i say the 125 just works and hopefully i can

just keep the winning streek going .I do not know what i would want to do to make it better it works that good for me I do know a 2009 is on order so i can keep getting those Husky bucks

NWet, i hear ya man, we all want more. You seem to be leading the way for us, but I think you'll like to hear this...I picked up a 38 PWK off ebay for a hundo, will let you know how it goes. I've also seen some in less than pristine condition go in the 60-80 dollar range. I plan on taking all three carbs out and running them back to back to see which is the best. I couldn't resist as all the euro 125's are running it, minus the KTM which according to the Motocross digital comparison had less punch than the stock Husky which didn't seem to be dialed in.

It's to bad all us tiddlers are so far away from each other, but between you, me ajax, joe/norm we got the four corners covered, haha.

I’ll be very interested in your 36 vs 38 pwk comparison. I debated which one to buy originally but went with the 36 for low end throttle response and mileage. I would really like to try a 38 though to see the difference. I found a couple cheap a while back but one turned out to be the wrong dimensions (from a KTM) and one had electronics I did not want (from an RM). I know the 99 and 00 CR250 has the carb I want but I am not sure what else. I can also get mine bored to 37mm. RB Designs is right next door for me and this work is cheap. It would still not be an airstriker though.

I am wondering if your 36 has the same behavior as mine. I have experimented with lots of main trying to get some top end. By seat of the pants testing I am using a 155 now (with avgas, probably a couple sizes too lean for pump). I later used my odometer to measure the top speed in 3rd with different mains. This confirms I have the right one. The weird thing is that, while the 155 has a slight bit more pull and rev, any other size is almost as good and the difference is really subtle. Every size from 158 to 175 feels exactly the same. The odometer test showed 45mph for the 155, 44mph for 158 – 172, and 43mph for a 175. I am not sure if this is normal or if something is weird with my setup. I would thing the 175 would sputter like crazy.

If you test both carbs maybe you could measure the top speed in 4th between them to figure out if it really revs higher with the 3.

I think I mentioned this before but the Turbine Core II is a nice mod. I wasn’t expecting any difference in power but I can pull a full gear taller in many situations. I was really shocked that it did this much. After the carb I think it is the best mod for the money. I had to lean the needle one clip for it.

Ajaxauto – I’ll try a CR if I get a chance. Others who have ridden both like the WR better for technical woods but it will be fun to test. I think the motors are identical between the WR and CR, the ignition is the only difference. If I like the way less mass makes the CR rev but don’t like what the timing difference does I will just lighten my flywheel. I have the service manual for the 250 which includes a graph of the ignition timing for the CR and WR. They are way different and I am sure they are for the 125 too. I would like to see the graph if anyone has it.

My cr125 has no bottom end to speak of. The wr125's I've ridden will pull better down low but even they are not tractors. Keep your piston /rings fresh to help the bottom end.

The CR does haul on the pipe though. The only 125 I've ridden that is better is a YZ125. the Husky is way better than a late model Honda or Kawasaki.

My cr125 has no bottom end to speak of. The wr125's I've ridden will pull better down low but even they are not tractors. Keep your piston /rings fresh to help the bottom end.

The CR does haul on the pipe though. The only 125 I've ridden that is better is a YZ125. the Husky is way better than a late model Honda or Kawasaki.

I need to ride a Wr because my 2006 CR loves the tight single track and pulls hard from the bottom up and seens to never sign off .It does riv quick must be the lighter fly wheel also the 19 inch rear wheel is lighter to get spinning

The Wr would be nice to try Cant wait to see the new 09 models


It's aways off, but you can ride my '02 WR125 at the NE Husky Gathering.

1) You're a little bit big, but you'll be suprised at how well they will drag you around, just be prepared to shift a bit. With stock 13/50 gearing it will go 70mph and still plonk in first. I've never really checked my mileage, but with the stock '02 2.9 gal tank I can do a 50 mile enduro loop, that includes everything from tapped out road sections to tight trail with gas to spare.

2)Steady tweaking of 125 through the years(no '05 in US) has improved power. '07 CR got a lower second gear, which I think would help in more technical riding('08 WR125 got it, but we didn't get it). 125's are more finicky to jet, but for your riding I think you'll be fine. They are still a little pipey, but powervalves make the transition nicer.

Search '04 CR125 and a couple of large threads should pop up from when Husky was selling these real cheap in '05. I always recommend the WR over the CR, as they are a little more tractable. Riding an '06 CR125 convinced me I could ride a 125, but a WR has been a better choice for me, also because I need the lights to ride Eastern enduros.

Go to Taskys and ride the any 125 you can find!:thumbsup:


Thanks Norm.:thumbsup:

I am 6 ft tall weight is 195 with all my gear including fanny pack and camel for mpg i am getting 20 mpg at race speed.Every race so far gets me about 20 mpg.I use stock gearing 13 50 and have not gound a hill i could not climb or do i want to go any faster in 6 th.For Baga aroung Tecate it would be great for faster stuff like up and over mikes it would be less fun.

As for the hieght of a CR 125 it is about half of a inch taller then a YZ 450 so

you will not feel as you are on a small bike.The wr 125 or 250 would be fun to try.As for a YZ 125 my son also had one before we got the Husky and i could not ride it as it was to pippy.As for plugs never fouled one at about 500

miles i do change them but they always still look good.My bike is a 2006

which just seems to work in 2 and half years of racing have change 1 piston

which still looked good and have also installed one ring .Still on the stock clutch ,as for jetting my bike works great stock i must have gotten lucky

If you come out to Luceren you can try it John

Does any one make a larger tank for the 2008 cr125?

IMS.... '05-'07 4 stroke tank fits '06-'08 125.


keep it pinned


i have the bfb cylinder kit and eric gorr ported it extra

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