125-200cc 2011 WR150 OWNER Keeping Mikuni 38mm Carb

Has any 2011 WR150 owners kept the stock carb?
I picked up my WR150 last week and need your knowledge to start working on reducing the bogging? At this time, I don't have money for a new carb plus a larger IMS gas tank.
I am hoping someone would share their hard work in figuring out the jetting on the Mikuni 38mm for the WR150.

I have a CR150 and ran the heck out of the bike today with the Mik.... had the Keihin and tried the Mik... well, I liked the Mik just fine. I have the RM 17 series needle with the stock slide. Check the jetting section for Mik jetting, slim pickens tho. Most have swapped out for the Keihin, get the tank now and carby later. good luck.

Look for some older posts that talk about using the Suzuki RM needle. That and adjusting the power valve will cure the bog. I would post up a link but it's a bit difficult on my iPhone.

Double check float level. Seems to be a major cause of bogging.

The Mikuni works fine on my 2011 CR 150 now that I got it dialed in properly. No bog. No issues. Seems like the WR 150 is the "problem child" when it comes to carb and bog issues. That, and the fact that many (if not most) WR owners seem to spend an inordinate amount of time and money trying to get their WR 150's to perform like CR 150's.

The Mikuni is still on my wife's WR125 (soon to be 144 thanks to Walt). I was lucky and able to get it dialed-in pretty good from the start. The biggest improvement was adjusting the PV linkage and Walt's springs. I do not have any plans to change it out, but have not ridden a WR150 with the Keihin carb.

JS

Thanks for the info. I have started rereading the jetting posts.

My '11 150 has:
460 main.
37.5 pilot.
Air-screw 2.0 turns out.
Stock needle (sorry, forget the number) on fourth clip.
4.0 slide.
Motul 800 at 40:1.

It feels fine to ride - very clean off the bottom and pulls strongly all the way through.
There's a dip in the curve between 6,000 & 8,000rpm on the dyno chart, but I'd struggle to call it a flat-spot. The dip was totally unresponsive to jetting changes - my gut feeling is that its power valve.
There's another dip around peak power. Again, not related to jetting - the dyno operator suggested it was a pipe related issue. This would seem likely, considering its the same pipe as the 125 uses.

Also worth noting that a 470 main made no difference to the AFR curve - presumably the flow up the "needle jet" tube is less than the flow of the main jet.

I'll get right into it after the new pipe turns up. This will include an RM needle and having a 35 pilot jet (couldn't get a 35 when I tried last Friday).

I have been re-tuning my TMXX on my 167. Runs awsome from 4000-8000' can't go higher still too much snow. 480 main, RM-17-62 needle in the middle slot, 27.5 pilot, and 2 turns out on the air speed screw. I didn't think I would ever have a new generation mikuni run this crisp over such a large elevation change. The bottom end was virtually as clean as the PWK and the TMXX has a little advantage from half to full throttle. Now the 167 is developing a little more vacuum pulse so those settings will probably change when I remount my 144.

Ok Walt! Where the heck can I get a 27.5!? I thought the smallest was 30. You always manage to find the uncommon jetting stuff!

I got mine, and a 25, at my local Suzuki dealer.

The TMX has pilots available down to 15. I know because that is where I was at trying to get the TMX on my WR 250 to idle at 8000' to 9000'. When you have an auto clutch idling is important. Try what Mark sudgested and if you can't find it local try Pat's small engine plus. They are fast and cheap. I still have all the numbers down to a 15. Now I don't rev the guts out on long straights alot and chop the throttle. I think that is where you can get in trouble with a small pilot and little vacuum pressure.

I think Jets R Us has them down to a 10. That is getting into bifocal territory!

A lot of information to use. I have been taking it slow because its been so humid in Southcentral PA. I believe the high humidity effects the performance of the bike.

I would keep the stock carb! On both my 144's a cr and wr the stock carb works great! Not even sure of my jetting! Both bikes from Halls, and have both run perfect (the CR, I had to lean the needle 1 clip to get rid of a slight bog, and real pipey feel.) My theory is if the other carb set up was so good, then WHY doen't ANYONE from Halls run it or suggest it for a performance increase or whatever it is supposed to do?? Both of my bikes ROCK!! And never run funny or give ANY problems at all with the stock setup. Call Hall's for jetting specs, and I'm sure they have ALL in stock to fix you up. Good luck!

we run Halls jetting on both our bikes, it works! after saying that i would still like to try the RM needle, as the stock needle is too big a jump between middle and one slot down with the clip. if i had a PWK i would try it also, but our bikes perform well now.

I love the RM needle on my CR 150. Works great.

I must say the keihin with jd jetting works perfectly on my '08 cr144

Stop Sunday and might let you borrow one to try to take back with you.

Glad it is working out for you.