125-200cc Walt's WR-144 Mikuni TMXX Jetting Revealed!

Good stuff there Thanks for clearing that up!! Now i have another brain teaser.. We all know that larger slide numbers equal a larger cut out of the slide bottom for more air flow, larger slide number=leaner. What i have never been able to track down with the Mikuni's is what that number represents exactly.

I am pretty sure that with Keihins, the number represents the angle of the cut, larger angle cuts further into the slide. But the cuts start at the same point. The number has nothing to do with millimeters.

I was told that Mikuni numbers represent the millimeters of material removed, but that would mean a fixed angle constant through all slide sizes. WHat i did to my 4.0 was machine the stock cut out 1mm larger based on the diameter of the circle.

Does anyone know what mikuni slide numbers mean exactly??

When I was at RB Designs I think he told me that it is actually a fraction of an inch. I think he said 5 is 5/8" 4 is 4/8", etc. I could be remembering wrong though but if you give him a call I am sure he can tell you.

I will measure up tonight on a spare 4.0 i have.

It is the opening size in MM, I Think

I have both slides here and there is a lot of difference. The 5.0 slide cutaway taper is wider and a bit taller. I just received my RB Designs modified carb and pulled the slide. Very close to a 5.0 except the taper goes a bit deeper. 5.0 on the left.

Celtic, quit playing with those Binoculars! Get that carb on and let's hear how she runs!

Wait, Celtic, so the left slide is a 5.0, and the right slide is a RB design modified slide? What did the RB slide start out as???

No the 4.0 is on the right. The RB Designs started out as a 4.0.

The RB looks about like the one i cut on the mill. I guess im surprised you have a 4.0 stock in your WR. According to the little usb thingy that came with my 11 the WR's got the 5.0 slide? Might be bad info. Hey Celticdude, can you post up some pics of the RB carb??

Yeah, the stock slide was a 4.0 plus Husky gave me a spare 4.0 as well. What's interesting is that the RB Designs shipping invoice description states: WR125 Husqvarna 2012 "Experimental Carb Mod"!

Celt,life is just one big experiment!dan

That Ron is funny

Iam running my RB Tmxx jetting like this

30 pj
16-62 - #2
470 main
1 1/2 AS
5.0 slide

This is with the carb bore to a 39mm on a 144

Thanks! I didn't go for the 39mm bore because I'm going for a big midrange hit.

Well Celtic,
We know there are at least 2 of them out there. I never really looked at my slip to see if mine was an "expirement" too. I received mine back from RB last Monday but have not had the time to ride the bike, I'm waiting for my needle anyway.
My WR came with a 4.0 installed and an extra 4.0 slide also. I did opt for the bore on my carb.

I've had my RB carb for a while now. I think it was the first one he did but I am not positive.

I measured the cutouts in my slides last night. The #4 is about 6.5mm and the #5 is about 9mm.

Is that an rb #5 or mikuni 5?

Both my slides are stock mikuni ones.

Is that height or width ? We need both.

that is the height. That was just a quck measurement just for comparison. I put my carb back together so I can not really take a closer look.

If you really want to cut one I would call RB and get the exact dimensions. He is a super friendly guy and likes to talk to people.