All 2st About the Mikuni/Keihin swap:

You damn enablers

Kelly has offered me a ride on his and I'm sure I'll be kicking myself in the ass for accepting. I've got the big bikes covered, so I'm kinda itching for something small and flickable.

I had to turn it in (clockwise) about 2 turns to get it to idle. But mine would start with the screw at the factory setting (I got mine from a Honda warehouse, so I have no idea where they set them from the factory). If 2 turns doesn't do it then try 2 more. Rinse and repeat.

Have you pulled the airbox boot and visually inspected the slide action? Can you confirm the slide completely closes when the throttle is at rest?

The only thing I can consider is the floats are way off and not allowing the bowl to fill with fuel or you have a clogged pilot jet. There's really not much to go wrong with a brand new carb as far as o-rings and viton plungers deteriorating. Or so I would think

Edit: if you remove the carb drain from the bottom are you seeing a decent amount of fuel dump out?

I loved that bike!
Smack pusher....

Well....I had my first chance to try out the Keihin on my 09 WR125...
the bike has roughly 1000kms on it..Maxima K2 3%

I headed out to a familiar spot and the wind was cold and blowing very hard....8 deg C(50F)...2500ft elevation(I normally ride at 4500 to 6500 ft)

Although I brought a full compliment of jets and one extra needle......I forgot my tool kit...and first time I ever did that...

So...fingers crossed...I was committed to run what I had in there....blue needle in the middle....45 pilot...airscrew 2 turns....and a 170 main that I installed at home...and also I moved the PV bolt close to the top just enough for the bolthead to cover the gap/slot in the arm....I found a 14mm wrench works wonders to hold the arm without ODing the linkage while you loosen those 8mm screws.....

First off....I did have my TMX dialed in perfectly..but practically wore out all the threads in the carb having to take it apart so many times...and it had a fluffy low end response that I never could get rid of....so on went the PWK

With the PWK it always starts on the first kick hot or cold ... right from the moment I installed it at home.....and a rock steady and clean idle too....the low speed response and driveability are amazing and dare I say very 4 stroke like....

Top end rush was noticeably stronger and more aggressive as well.....

BUT...although the middle was clean and without a hiccup pulling through.....there WAS an annoying flat spot that would appear suddenly on fast whooped out straights on and off throttle..but mostly during a downhill as the suspension compresses fully as you hit the bottom and the throttle is opened......I would brace for the power hit....and get nothing....I did the COBRA a few times ...and rode more tentatively after that....

I'm going to lower the fuel level a smidgen and retry it.....


MattR.......when I get this sorted.....I'll put it in the jetting thread.....

Today, i have finally start the bike ! The trouble was the idle screw way off by about 5 turn !!!

Now the bike start always in one kick.
My current jetting is 178 main, 42 pilot, DDJ needle in 2nd (from top) and air screw at 1 1/2 turn..

The bike have no trottle response... and the low end is very sluggish...
The mid is really strong and the top end pull like a champ with the front wheel goes up in 5th !!!

My trouble is really the off idle and trottle response in the lower range, totally off.

Do you think i can go lower than 42 on the pilot ??? I have absolutly no response and power in the bottom. ???

With the Mikuni, the bike pull like a tractor and have instant response in the lower rpm range.

What temp do you have? How is your idle and how far out is your airscrew? Have you tried to raise the needle?

Thank you for your help !!!

The temp outdoor is about 65-70f.
My air screw is 1 1/2 turn out.
The idle is fine.


Raise the needle ????
I have the impression that my off idle and trottle response are way too rich. I can try, but i really doubt.

Anyone know what is the equivalent of the N3VE in the regular Kehin needle part # ????

Rode on Sat. between 1500-2300' (I'm guessing) and temps starting around 50f in the morning and getting to 63f by the end of the day. Jetting was 45/175/N3EJ #2 clip. At the beginning of the day it was perfect, but the bottom end began to really feel fat as it warmed up throughout the day. Mid and top were not quite as crisp as there were in the morning, but were acceptable. I think a 172 will be required now since its warming up.

With temps in the 60's and riding anywhere under 3k' I'm going to run a 42/172/N3EJ #2. This is an 09' WR300, Keihin PWK 38 and Pro Circuit Plat. 2 pipe/type 296 silencer

Is that the needle that came with the carb? If so, what bike did the carb come from?

I ordered my carb as a replacement carb for a 2000 Honda CR250. Whatever needle it came with from the factory was very rich and my WR did not like it.

I'm now using the N3EJ needle (came stock in my 06' yz250) in the #2 clip and its a huge improvement.

Well, it depends on how it behaves. if it´s like Bvoooaaah when you twist the throttle that´s usually lean, but i guess youknow quite well what you´re doing. It´s obvious if it smokes a lot too.

Thanks.
The DDJ needle came stock when you buy an aftermarket PWK AS. Its not for a specific bike.

Do you think my problem can be caused only by the needle...?
The bike is close to unridable in lower rpm range. No trottle response.

I dont want to go back with the Mikuni but im close to that

Oh yeah. Look at this tuning guide:

Its nice to have a visual aid.

At the very least try a leaner needle and see what happens. I wouldn't put the Mikuni back in my 300 if it was the last carb left on earth! Well... that might be a slight exaggeration

If it´s that bad and doesn`t bludder or smoke very much when you open the throttle it sounds like it´s too lean. Make a test. Raise the needle two clips and see what happens. have you checked that the needle isn´t for emission legal jetting? I´m not so familiar with those needlenumbers.

Johnny

Do you have de spec of the blue JD needle ?

The JD specs are a close guarded secret. How else can he sell 2 needles and a few mains for $80

How much slack do you have in your throttle cable? When I installed the PWK I could not get the stock cable tight and my slide was not opening until about 1/4 throttle. I had a real lack of low end response! And no top end since the slide wasn't getting high enough to flow fuel through the main. Once I rerouted the cable to take up the slack it's been a pleasure.