125-200cc Keihin vs. Mikuni for 150

NWRider, that's the main thing i'm worried about with the Mikuni, random performance

how do i know if i have the TMX or TMXX? carb came stock on '09 WR125, is it the XX?

anyone have a manual for that carb? i'm digging around right now for one...

http://www.startinglineproducts.com/catalog.cfm?pageID=detail&catalogID=3&catID=21&productID=355

I usually set all my carbs (PWK, TMXX, etc...) with the pilots and mains. From there you can dial a carb in from the top with a 1/2 clip .020 needle shim. I am going to be using one in the PWK as well. Saturday we went up in temps and I had to change my pilot. Next time the temp drops, I will slide the shim in. I usually use them in 10 degree weather increments so the bike always runs the strongest. When not in use, you store them up on top of the clip so you don't lose it. Call these guys, they have them and are close to you. If they are out of them, let me know cause I might have an extra, I can send.

I ran the bike this weekend at the Cajun Classic Nat'l Enduro. I got 5th after a weak showing in the first section but the rest of the day went pretty good. Im running the Keihin PWK 36mm Air Striker from the 2011 KTM 150XC. I am running the 170 main jet (Stock), 6.0 slide / throttle valve ( stock is 7.0), NOZI needle in the #3 position (Stock), and a 35 pilot jet. I had to adjust the Air Screw out to 3 turns. ( I plan on dropping it to a 32 pilot. IF I CAN FIND ONE).
Carburetion was very very good. Bike ran better than ever. Little to NO sooge at pipe connection.

After adjusting my float level AGAIN, my milage has now gone from 14.3 mpg to over 18 mpg. At first gas stop I figured I was getting about 20 mpg. Next two gas stops I was getting a bit over 18 mpg.

Does anyone know how the Mikuni "RM" needle codes work? I have a 61 now. Is there one made that is half a clip richer, or do I have to use shims?

Vinduro - The milage is one of the main reasons I have thought about the 36. My old 06 125 with a 36 used way less gas then my 09 144. I am not sure if it is the 144, the different ports on the newer cylinders, or the carb size that is to blame. From your results I think it is the large carb.

not sure if this info translates to the 61 codes as well but...

in my discussions with Walt, i mentioned i have the 6CHY16-62 to try out... he said the 6CHY17-62 needle is half a clip richer

So why does one motor work well with XYZ carb and not the next guy with exact same motor, etc...? Why does one motor outperform the other one?

You take two exact 09 Cylinders. One has the transfer ports ground better to a point, the other looks flat 1/8" wide, like they forgot to detail them? Has to affect fuel transfer to the ports?

One cylinder has terrible casting marks. protruding in the intake transfer ports. That has to affect fuel transfer, the other is smooth?

One stock powervalve spring, I can change out with one hand and use the other hand to slide the pin in. The other takes me two hands to push down plus someone extra to slide the pin in? Same part number as 2006? Was the spring tension changed? Are their bad springs out there?

One set of cases, I had to take alot off to gasket match it to the cylinder. Other one I have to trim some of the gasket material with a razor knife and it is almost perfect?

Why does one exact engine with WR ignition have more torque than the other with the WR ignition? Same carbs tested, same pipes, same silencers, same timing spot? One of the carbs won't run on the other engine, as good as the other?

Why does one carb work on the WR Ignition motor and you use the exact same carb/settings on the CR ignition motor, now all the settings have to change?

Alot of assembly line mass production affects things.

The best motor going is the one I spent alot of time, grinding/polishing/matching.

Some of this is just in your motor. The other one, I basically left alone till my 144 Cylinder gets back.

I'm a bit confused on the RM needle codes. If you search a Suzuki OEM parts fiche for the RM 125, It shows a range of needle options like this:
6CHY17-64
6CHY17-63
6CHY17-62
6CHY17-61
6CHY17-60
6CHY16-64
6CHY16-63
6CHY16-62
6CHY16-61
6CHY16-60
Intuitively, it would seem like the next richer or leaner needle from the 17-62 would be a 17-61 or 63? I'm always bumfuzzled by needle numbering codes.

PM me your fax number and I'll fax the RM manual pages to you for tuning.

You can use any 16 needle and if you want a 17 needle, you just put a 1/2 clip shim under it.

Mark, your bike was running great!
It seriously felt like it had double the low end of my 125.
It felt like it has less flywheel effect and was much more eager to spool up the RPM's quickly as where my bike would labor until it finally got on the pipe and then it would rip. Our bikes aren't too dissimilar except for the 144 cylinder and Ron's tightened up your head. And I dont think those would make THAT much of a difference.

Not sure if I went too far on the PV adjustment, the jetting was way off (I was super fat on the pilot as it was spooging & fouling plugs) or my timing is not properly set. It almost felt like you had advanced timing and my bike felt like it was retarded a bit. Your bike flat ripped on the bottom and mid compared to mine.

Can you list your mods and jetting for that day?

Brandon – I think your bike just needs some jetting. I’ve been on small bore Huskyies for a few years and believe me, jetting makes a HUGE difference in how they run. Especially on the bottom.
I think with your power valve adjusted all the way up it might hurt the top end but I don’t think it makes any other difference. I would get the bottom sorted then adjust it again to where it just puts some tension on the spring to keep the valves slammed shut. As for the timing yours is a CR so you should have a mark to check.

That being said here is what I have done:
.2mm removed from head by RB Designs.
Power valve adjusted to where there is some tension on the spring (about ¾ up)
Burning straight Avgas with Lucas premix, 32:1
Fatty pipe, TC II silencer
CR Ignition from an 06. Advanced about one degree.
Stock carb: 35 pilot, “-61” RM needle in third slot, 470 main. I am not sure if I have the 6CHY17-61 or the 6CHY16-61, I need to check tonight.
12:50 gearing (because it came with the bike), I will go 13:52 soon.

It pulled even harder when I had Walts power valves in it. I also had the PWK on that day so I will test that carb one more time to make sure that is not the difference. With the cut power valves I found it worked best on slick hills with the timing retarded a couple degrees. It was just smoooooth all the way up. With the timing advanced as I have it now it was a fun but a real handful. I have some even better power valves on my bench so it will be interesting to see what they do. I will probably do the carb divider(or a 36mm) next so it should really have a lot of low end for a small bore.

Darin,

I actually enjoy that these aren't cookie cutter bikes. Each one has its own personality and takes its own set of adjustments. Not fun if you don't like mucking around in the guts of your scooter but for an old fat B*stard like me it is heaven. Of course if you asked me what I thought in the first few months of ownership of the WR125 my answer would have been unprintable.

I can attest to jetting having a huge impact as I believe the stock needle was too lean and causing the massive bog I was experiencing. Even switching the RM needle from clip #2 to clip #3 had a profound effect... much more so than I've noticed on the bigger smokers.

Riding your bike was a bittersweet thing. It was bitter cause it made my bike feel like a lethargic pain in the ass, but sweet cause I know what the motor is capable of now.
I'm going to bring a PWK 38 next time and try that out. The Mikuni just does not like elevation or temp changes and is a freaking hassle! It ran great at Eddieville, but that was all WOT riding. The forest with its big elevation and weather changes was not so much fun with the Mikuni. I may bite the bullet and get the PWK 36 for this bike. I forgot how much hassle the damn Mikuni's were.....

Here's an example of the little stuff that makes them so addorable. I was ripping around for about 30 miles on Saturday in the Owyhee's before the race on Sunday. I had just installed a carb vent line filter that was new to me. I layed the bike down at the end of the riding(stop and flop with full kick stand intrusion). Loaded up the bike and headed up to the staging area to see if I could hook up with Ajaxauto and any of the Boise Husky crowd. Found Ajax and got to talking with him about all things husky and riding. Walked back down to look at my 167 that had ripped it up all day giving nothing away to a nice running KTM 250 2t(I have video). John wanted to ride it so we unloaded and I met him back up at his van. I rode the bike up there after trying to get it to clean out??? John rode it and complained about it being really rich and all the spooge that was coming out. Changed plugs, no help...scratching head wondering if the main jet had fallen off. I limp it back to the truck and pull the carb. Nothing is obviously wrong. Buddy looks at my vent line filter and says to pull it and check for a plug. I pull the cap and about 2 ounces of gas run out. Clean it out, wick out the filters, re-install a single filter and start it up. After clearing out what seemed like a cup of extra gas from the crank it is back to ripping. John still has no idea what a 167 runs like. I also still had the flywheel weight on it from trying it out in the rocks around Bullhead City and that wasn't an advantage in the great traction and sand in Boise.

I'm going to resistant messing with a good thing. Had the bike at friends place this weekend and it was still ripping throughout the entire range. Although! It has been about the same temp/humidity since we got it right.

I do have the Mikuni on it and have the 38 PWK Quad and the powernow insert for the filter side sitting on the shelf. I have been thinking about selling it and dealing with what I have when weather changes.

It was actually nice to move on to other issues like suspension tuning for different tracks. I think if I did switch to the pwk I'd look at the 36mm. Anyone interested in the 38 pwk setup I have on the shelf? It came from motosportz with the jd jetting. Might be a mistake to get rid of...?? Just was not the silver bullet I was looking for...that was the cr ignition.

Dwight,
Why when I go to the KTM site and pull specs for a 2011 150XC, it shows Keihin PWK 38 S AG as the carb?
Norman

I see the 36 here...
http://173.74.246.25/munnracing/cat...=652745&year=2011&model=&component=CARBURETOR

Quit looking a the specs for the 2011 150SX.

Seems there is no such thing as a 32 pilot for the PWK . 35 is the smallest. I really don't want to hurt the 1/4 - 1/2 throttle range as it seems good. I want to lean out the 0 - 1/4 range. Should I be thinking about a 6.5 slide ? I keep finding that the bike wants more air screw and it is so far turned out 3 turns. It seems to like 4 better. I want it in the 1.5 to 2.5 range. I am looking for a jet or situation that will give me highest idle in that range. Suggestions ? I don't have a 6.5 slide and really don't want to pay KTMs price for one.

Yes, thats for sure but I am also glad that what I found inside and fixed made a 150% difference in the 06 engine. Actually, I am putting a CR ignition on his 06 because it has way to much torque on the bottom and all it wants to do is wheelie in 1st-3rd. I know that when you send the 144 Cyl back, I am going to pull an allnighter getting mine dialed in pretty quick.

Dwight,

I think most of these KTM's came with the 6.5 stock so you might check fleabay for the 6.5 slide