125-200cc 09 Wr 125 Bog/Performance Solved?

I purchase my 09 WR125 spring of 2010. Seemed to be perfectly jetted from Hall's. Raced my first race and the bike bogged terrible. Got disgusted with it and put it in the barn. Later, i jumped on my son's RM125 and it way outperformed my Husky. I almost sold it and bought a YZ125. Could never get the carb to keep from bogging from one day to next without needle or airscrew adjustments.

One day, I took the carb off the Husky and put it on the RM (Same TMXX carbs). RM bogged and ran terrible like the Husky. Took the needle and 5.0 slide from the RM and put it in the Husky. Bike started ripping like it never has before and I knew I was on to something.

Even bought the PWK 38 AS and this was a big improvement, but I lost top end.

I purchased all of the 04 Suzuki RM 125 needles/5.0 slide, After 3mos of work with all the 04 Suzuki RM125 needles, the RM 5.0 slide, pilot jets and main combos. The bike finally rips the best it ever has and has a great top end. Seems, you only need to do some clip moves when the weather gets colder.

I also used Walt's stock and silver spring combo from his kit. That was a big improvement as well.

Here are the settings that got rid of the bog and woke the bike up!

I ordered these parts from an 04 Suzuki RM 125

5.0 Slide (Kawasaki sells the 5.0 slide a little cheaper off KX125)

6CHY-16-62 Needle (Middle Position and was best needle)

45 Pilot

460 Main

40:1 Amsoil Dominator

65 Degrees +

Elevation 900 ft

Powervalve spring kit, used stock/silver spring, adjusted 3/4 way up.

Update: Guys running the CR ignition, usually need a 35-37.5 pilot.

Thanks for your tipp, Great info.

But i wonder if you changed your powervalves, before you changed the carb? It was a fix from Husqvarna (factory) on that model.


Best regards Klas

Sounds like what I am going through with my wr125(09) My 05 yz125 will tear it a new one. I have tried the carb parts swapping as well and also feel that a richer tapper is the answer to part or the problem. What about ignition? Cr vs. Wr? Is the WR dated? No variable timing via. CDI box? I have a dyno at my shop and just got a street tire to start getting real answers that nobody seems to have. I also think port velocity is an issue as well. The wr needs more fuel to still be slower than the yz!= not burning the fuel as good and all spoog wr; yz no spoog. Reed cage on wr big, yz small and better velocity.

The '09 came with a 5.0 slide stock and then the power up kit had the 4.0 slide. Between the stock Husky carb set up (5.0 slide) and the power up kit (which has 460 main jet and 45 pilot), all you should need to buy is the Suzuki needle.

Typpt
Thanks for sharing - I am sure there are a few users who will find this very useful information
Do you know if the slide suits the older Mikuni as well ?

As Norman said the lack of needle alternatives was always the majority of the problem. Great find with the RM needle. YZ's all run with 70's series needles. I think the PWK will still have a slight advantage on the bottom end as I have not experienced the bog with that carb you have. Different elevations and humidities make a difference though. Being a slow old fat guy the bottom/mid is where I live alot.

Walt

Because the YZ and RM work fine with this carb I thought a Keihin replacement should not be needed. But by the time I bougth my WR people still could not get it to work so I put a PWK on. I thought the problem was needle selection. But now I guess people did not find all the needles that are available for this carb? If there are some needles that work with the Mikuni I wouild not mind trying them since it fits a lot better then the Keihin.

Did you try to jet your Keihin? You will certainly lose some top end if you run the main that came in it.

Oh I pray your on to something here! It makes sense to me, for now.

Thanks for the info.

Perfect! the '10 came with all the goods required, except the needle. I have another not sure what it is. I'm on it:cripple::canada:

So would this work on my 2008 cr125 with oem 144 kit on it with stock carb with 30 pilot, 400 main and I believe stock slide is 3.0 with a 60 needle . My bike is better with 144 kit but still not as quick a throttle response like boys yz 125. Thanks for doing all the work to figure it out

I just found out my tmx38 carb is not the same as 09 newer bikes. I should have looked in jetting fourm first.

I have a 5 slide that came with my 09. I bet there are plenty of them out there gathering dust so if anyone is looking for one I would suggest putting an add in the classifieds before spending $114.

I already have a PWK but I am curious if I could get the TMX to work. The PWK is really hard to install and it makes my airboot rub the shock. But it works and I know it so I am not going to spend a whole lot of time with the TMX.

There must be a reason the YZ and RM come with the Mikuni. I believe both of these use a Keihin on the 250 so why did the factory choose the TMX for the 125? Is it because it works better on a 125, because it works better on the dyno (high rpm), or for cost?

So my next question does anybody want to sell me there newer tmx carb with 5 slide and I will try it on my 2008 cr 144 it should be as easy switch. If I could get my bike jetted like my son 2010 yz125 with the 144 kit on the cr it would great out on the track. Like I said before it still better than before when it was a 125 but just needs better response from start to high.

Pedec,

The older TMX is the same dimmension as the PWK which is about 1/2 inch longer than the TMXX. You will have a hard time getting your intake boots to stretch enough to give you a solid connection.

Walt

Thanks for the help. I guess I will just keep trying different jetting

Great, come buy mine so I can get something else. It's only a month old and yours for 3300.

I want to agree on paper with what you found and I'm gonna try pulling my PWK off and try your recommendations on my TMX. I really liked how my TMX ripped on top and how it fits better. Thanks for the info! It should work as I'm at the same elevation here in NC!

This matches with my findings, it needs more fuel off the bottom, although I know some of the bikes work well with the leaner settings. Don't really understand why some bikes work so well lean but others like mine won't get away from the truck until you richen it up. talked to a guy that raced cagivas back in the 80's, and he mentioned that no two engines were alike! I had my mikuni working well with a 45 pilot and a 480 main then used the #5 slide to lean it out through the mid range. I am sure with the suzuki needle it will work even better.
I am running the pwk now with a NOZF needle which is richer than the JD blue. I think if Darin spent as much time working with the pwk, he would get it working very well also. Just got a ktm pwk 36mm that I am about to try.
To answer one of the other questions, I believe the mikunis are very good on the top end, and most 125's are mx bikes where you are mostly concerned with top end. Also, mikunis are cheaper which lowers the cost of a new bike.
GP

Just to be clear, you said the RM uses a .64 needle but you also said to order the following:2004 RM125 needle 6CHY16-62 Suzuki Part Number 13383-36FQ0 $11

Is the .62 an optional RM needle?

Also did you get the bottom end as good as the PWK? The Keihin seems really good for running clean on the bottom. I put a DCL in mine last weekend and it is really crisp. But since I have the TMX anyway I might experiment if it just cost me a needle. I have the rest of the stuff from the power up kit.

Oh, has anyone tried the JD needles for this carb?