All 2st About the Mikuni/Keihin swap:

Thanx guys. This has been a learning process for me. I like the bike and I am enjoying off road riding, but there have certainly been some dues to pay!

I have been reading everything here about the carb swap on the 300 and now I have finally ordered a PWK 38 from Motosportz.

Whats been bothering me is the amount of smoke coming out regardless of oilmix and jetting, I really hope that will improve with the change of the carb and I really looking forward to see the result.

Will be back with a report later on

Trying to fit the PWK - fitted on Ok
a bit close to shock spring
having trouble with the nipple ! the cable nipple seems to be too big to fit down the side of the spring and into the recess
a real bugger to get in.
the plastic cap on the spring is also getting in the way do I have to take it off ? It has a knob on it which slides in to the needle bolt
nipple cant go down far enough down to the little recess

I cant believe it I bought a Keihin for my WR125. My pride as a tuner made me want to get the Mikuni right, some days it actually worked OK.
I talked to our local pro last week, sponsered Husky rider, and he told me to spoil myself. Both his 144 and 300 have a Keihin. Got my carb today
and will be installing it this week. Cant wait to try it. back later

You will need the NOZF needle if you got the 38mm. NOZI if you get the 36mm. Check the jetting forum for the lastest jetting specs.

I have a PWK and just took it off I like the TMX better seems to over rev better , I know it go,s against everybody here but mine cranks better with it and runs better with , and I dont fool with the jetting anymore then with the keihin but I,ve got a weird 09 WR250 super strong and fast other WR 250,s I,ve rode don,t run has hard , but mine run,s flat quicker then others but thats just the nature of beast , I guess , works for me .

My '09 WR 300 ran like a scalded dog with the stock Mikuni. Never had any issues getting it dialed in.

I did the jetting on my 08 WR250 and it has the TMX. It flat out rips as well. The only Issue is that the powervalve wasn't adjusted at the specs from the factory.

I think the biggest issue with the Mikuni is my lack of knowlege on there needle # system. I think they could be made to run well. The keihin seems to work better in drastic elevation changes (3000 ft) in the same ride.

What Troffer88 said!!!

hey gang. I'm having an issue getting my main circuit dialed in. I have a sputter that hits up top, then it revs out like it should. My current setting is an 09 300, pwk, jd red on #2, 40 pilot 1.5 turns and a 168 main.(175 was way to rich 170 did the same, talked to JD and he suggested 168) My recent rides have been 4000-7000ft and between 40-70deg F. It starts 1st or 2nd kick every time. Idles great and runs amazing up until just shy of revving out. It sputters and then gets on with the biz. Any other High elevation 300''s, what are you running? I don't want to lean it too far and fry a piston on a fast section through a sandy wash.
Now with the JD blue #2(how carb came set up), I didn't have that problem up top, but it was way too rich down low. I know the red is richer up top than the blue, but don't feel like a 168 would sputter. Thanks.

try lowering the needle height - that will fix it to 3/4 throttle
I had the same thing with my PWK

so, are you saying to go to clip #1 on the red needle? Where is your location?

Worth a try to see how it goes - easy to do change
I think a lot of people have one away from the JD needles - refer to jetting database
I do think the needle is the trick with tuning these PWK carbs
I am in Qld -

I think the CEL works alot better than JD needles for the 300

Where can we get the CEL? Motosportz?

Pat's small engine plus has the best price jets and needles that are standard Keihin parts. The CEL was the best needle for both my WR250 and WR360.

Any idea where I can get the CEL or EEL needle in queensland? Currently using the red JD needle in the top slot which is great but I would like to try CEL/EEL if I can get them.

no mate sorry - I got my carb from Kelly and used the red needle - Pats small engines - as Walt said

Might be the biggest variable, more than elevation is the rider. Plenty of guys rip with the Mikuni. Did Husky not add a thermostat to the 2T? Maybe to try and keep the operating temp., range more consistant, make it easier for those riding off the pipe? Would like to see a straight up fuel consumption comparison though.