125-200cc Bone Stock 06 CR125 - No low end power

I recently purchased a 06 CR125 for my son. Bike is in very good condition and completely stock. Bike starts great and runs cleanly at high rpms. Problem is it has very little low end grunt. This is our first Husky 125 - previously had a 05 KTM SX125 that had lots of low end power. From those who know...is this a characteristic of the engine? If not, where do I need to start looking? Haven't had the carb apart yet so I don't know what jetting is installed. I'm in Missouri (about 900' elevation). I have swapped out the original rear sprocket for a 52T steely. That's the only change. Any advice on carb settings would be great.

Thanks,
David

My 2006 CR 125 is bone stock except i have a FMF pipe with a Turbine core spark arrestor on it .Tons of low end this bike has been race for 4 years and has won 2 different AMA National #1 plates in both 125 a class and 50 a class My carb is set as delivered from the factory there are people on here way more smarter then me as to how to addjust carb and maybe power valves. Try looking at the
pipe to see if all is flowing no carbon build up
Like the name of your town same as my last name john

David,
There are several topics in here regarding jetting/carb/power valve springs that I have found very helpful. You can do a forum search or just look on the first page. I had a 2006 with similar issues compared to the 2005 yz125 I was riding. You will have to play with the jetting as the mikuni carb is finicky to say the least. Just when you think you get it dialed in it will change on you! Another great topic is the power valve position and springs. Take the time to research these topics and you will be thrilled what the Husky 125 can do when tuned properly. Good luck and enjoy your new ride!

As Ajax had mentioned.....I dont believe there to be issues with low end power on an 06 CR125.....perhaps the transition from the bottom to the very healthy midrange and top end makes the bottom seem weak...it might be a bit weaker than the KTM on the bottom...but not a world of difference..IMO

make sure the air filter is clean...pilot should be somewhere around a 30(35 is stock)....needle might have to go up a notch if you have a flat spot....

Lots of folks feel the 06 and previous years might be the best engine spec to date....

Make sure the silencer is fresh with good packing and all the holes in the core wire brushed open

Check the operation of the power valve - if it is stuck open you will loose the bottom end power.

On my 2008 cr 125 I went down one size on pilot jet from 35 to 30 which helped alot also adjusting air screw depending on temp helps also a 1/4 to 1/2 turn make big differents ( screw in on cold days to richen and out on hot days to lean out) mine is set between 1 1/2 to 2 turn out most times . There is still a small flat spot off bottom to mid but very small. Just keep motor in mid to upper range seems best. I have just got use to it I guess and love the way motor rips on top lots fun and very durable so far. I did put a smaller front spocket on which made it alot easier to keep revs up which you already did.

Our 04 requires odd jetting compared to our others, had weak bottom and would bog when opening the throttle for a moment and then take off like a scalded dog. I ended up at 25 pilot needle raised all the way to bottom notch, 380 main power vale just a touch down from top. 44:1 silkolene. pulls smooth all the way through with a good hit on top no hesitations burbleing.

MY 06 WR 125 WAS week down low. I think its just the way they are. My 08 is better. But no YZ 125. I recommend leaning pilot jet too. And leaner needle setting.

My sons 2010 yz 125 has no hestaition of bottom, perfect jetting and very good low end right from new. The funny thing is they have the same carb.

In essence your correct.... but Husqvarna used an older version of the TMX up till 09 and its different mostly in terms of the slide shape....also a few other small details

for eg some of the Japanese 125s have a TPS sensor used for igniton timing advance curve...and other uses in the ECM

the YZ125 i rode had alot smoother pull on bottom but not nearthbe pull on top as the husky.

the husky has a better bottom end (crank bearings) then the YZ's IMHO.

is you power valve linkage hooked up?

Lots of mention regarding the power valve. I'll have to check the forums and figure out if our is functioning correctly. It's also interesting that there are several references to YZ125's. I sold his 03 YZ125 to get the Husky. The YZ also had a healthy low end. I think I'll check the main jet and the needle first. If that doesn't help, I'll look into the power valve.

Thanks,
David

pv link is easier to get at then checking your jets.

Any tricks to determining if the powervalve is operating correctly?

peel the cover off behind the expansion chamber...pop the linkage rod off and move the lever attached to the cylinder head it should slide smoothly without sticking

if it feels smooth..pop the linkage rod back on and start up the bike.....

rev the bike through the mid and upper ranges...it takes a bit of RPM to get it there...but you will see the PV change position.....it will move quickly so watch it closely

I think its probably OK..not usually a problem unless the bike has been incorrectly assembled...or is coked up from running wrong type of oil

also on the 06 there is a drain hose that comes off the PV housing that needs to be drained after every few rides....its the hose on the left side that has the cap on it..pull it off and let it leak out....but watch out the goo doesnt get on anything.....its messy and also blacker than Loon dung.....