Attn: 2002/2003 CR250 Keihin PWK Converts

It's the porting more than anything. I'm running a 162 main in my EG-ported CR250 myself, compared to a 175ish main for a stock CR250 using the same carb I am (2000 CR250 stock; I'm running a PWK from a 2000 on a 2002 CR250). I just wanted to make sure it isn't a typo.

Most importantly, I thought Faded sold his CR265 for that infernal CRF450 he rides now.

Just say no to fart bikes!

His CR265 is still for sale :bang: :ahhh:

Looks like I'll be ordering some more brass since I only have down to a 162 at the moment. I might as well go all the way down to a 150 since a 265 kit is in the long-term plans.

As for selling the CR265R, I think it is Fate's way of telling you that the fart bike needs to go.... ;)

As for selling the CR265R, I think it is Fate's way of telling you that the fart bike needs to go

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Agreed

skipn8r said:

Elevation: 5,000 - 6,000 ft
Temps: 60's

Mods: Doma pipe, VF3, Uni Filter

Main Jet: 175
Needle: DEK
Clip: 1
Slow Jet: 42
Slide: 7.0 (stock)
Air Screw: 2 -2.5 turns

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Updated jetting for my PWK
Main jet: 165
Needle: DGL
Clip: 4
Slow jet: 38
Slide: 7.0
Air Screw: ~2

No spooge, no bog, still experimenting.

Thought I would bring this back to life. I've got a leftover new '04 cr250 with about 5 hours on it (all stock parts) Now I'm installing Platinum 2 pipe, 304 shorty, and Boyesen Rad Valve. Thinking of Keihin PWK to eliminate future headaches. Anyone done it to an '04 yet? Were you happy?

Faded said:

Or you can disconnect the TPS and run a standard PWK but there's no telling what kind of results you'll get going that route.

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wont disconecting the TPS affect the timing? TPS stands for Throttle Postion Sensor, which means it does not regulate anything in the carb, but only measures the throttle positon, so un-hooking it could cause problems with your timing advance and retard........correct? i would think you would have to also change your CDI if diconnecting the TPS.

I'm still waiting for the jetting headaches to begin. I've been riding the bike alot lately and the jetting seems to be spot on. I did drop the main one to eliminate some spooge I had on long straight aways but other than that I've been happy with it.

Faded,

I'm going to pull thig thread from the grave again. I had a change to pick up a stock 2000 CR carb cheap so I figured I give it a chance and offer a back to back comparison between a JD jetted Mikini and the PWK. Thats the plan anyway.

So as a recap today it was 65 and low humidity at around sea level. The bike is an 02 with a gnarly pipe, PC silencer, boyesen reedblock, Eric Gorr porting for low to mid with bumped compression running on 100% sunoco 100 (unleaded 2.7% oxy) and 40:1 MX2T.

The PWK was set up with the stock needle and I endd up with the clip in the middle, 162 main, and a 42 pilot. AS 1.75 out. After messing with the carb for the better part of two hours (at the track) the bike is still what I would call unridable but it has potential. Here's my problem, rolling along at low RPM in 2 or 3rd gear, if I crack the throttle fast the bike will bog before it comes on the pipe. It feels lazy coming on the pipe but when it does it hits violently and almost uncontrolably. Thinking it was a lean pilot I ran the pilot up to a 48 with no improvement - still flat and bogs. If I roll on the throttle slower it doesn't bog but still feels lazy. I started with the needle in #2, then 3, then 4 with only minor improvements but not enough considering changing 3 clip positions. I'm fairly certain the 42 pilot is correct as the air screw noticably adjusts the throttle responce on the stand. With the 40 or 45 the AS has less affect.

I'm looking for ideas as to what is causing the bog/lazy feeling and potentially a recommendation for a different needle.

I have to be honest, right now my JD jetted Mikuni would out pull the Keihin all day long from the low end through what little over rev I have (remember its ported for low-mid).

Any suggestions?

what is this popular auction site?

pace said:

I see there are several PWKs for sale on that popular auction site if anyone is looking for a used one for cheap..

Just search for 'cr250 carburetor'

-pace

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what is the link to the auction site?

ebay

Well I finished up my conversion today. I just swapped my Mikuni for an 00 pwk and even with the stock 00 jetting this thing runs much better. I have not even dialed it in yet and Im super happy. Best $56 dollars ever spent on ebay.
-Zach

I throw in my exp.

Pretty stock low hour 2005 cr250, used for trails. Bought it because it was a steal. Didnt like it at all for woods & single track initially and thats all I ride.

Spent several hours trying to rejet with the stock needle to no avail. Whenever I would get close with the jetting, the bike would either ping or the plug would show lean.

Ended up getting a used carb off of a 2000 cr250. Came with a 45 pilot, stock needle, and 172 or 175 main. Instant improvement (smoother) in the transition from mid-range to on the pipe. This was noticed in the initial couple runs up and down the street in December.

Waiting for spring, I picked up a JD kit for a YZ250 (also uses keihin) and a JD kit for the stock mikuni carb (both were used and cheap). In the spring I rejetted teh keihin with the JD kit and did multiple plug chops/checks. The bike ran very good with this kit, seemed to smooth out the power and ran very well from the mid-range upwards.

I then spent some time with the keihin and the JD jet kit. Did many plug chops with this setup also. I dont think this had quite as much in the mid-range up, but really smoother out the lower end, made the bike much smoother thru all transitions.

Keep in mind the jetting was done on a straight dirt road.

Then I took the bike out on a couple rides with each setup. Although the JD jet kit worked very well on the mikuni, it still remained finicky to moderate temp changes requiring several airscrew adjustments throughout a days ride. And I would still run into boughts of pinging, tried to adjust it out with the AS, but then the lower ranges werent as nice.

With the keihin, I would normally tweak the AS at the ride start up and then forget it for the rest of the day. And being that it smoothed out the power all around it made for a much better trail bike.

If I wouldnt have swapped to the Keihin carb, I would have resold the bike, but with this carb and a few woods mods (sprocket ratio changes, flywheel weight, boyesen power reeds, and oversized tank), I like it just as much as my KTM200 which is newer and cost me a lot more money up front.

The downfall of the carb is that it does not fit into the carb boots as well as I would like. When I rejet (loosen the carb), I need to have something (long screwdriver or prybar) to push the carb forward into the intake reed intake.

So can you just put a regular 38 airstriker on an 2001 250 cr or do you have to have a special year because of the tpo thing? :whoa:

2000 pwk and 2001 mikuni dont have tpos. Can swap with the only issue being the slightly different carb boot fit.