which carb for 05 CR250R stock Mikuni with power jet or JD jetting Keihn PWK without PJ

I went a pwk short body on both my 06 cr125 and 07 cr250. both bikes ran sooo much better and no more constant jetting changes. Go the 36mm if you want more bottom or the 38mm if you want more up top.

Be aware that the 05 CR250 Mikuni TMX does not have a powerjet. It has a throttle position sensor TPS, but no powerjet circuit.
The Keihin PWK short body air striker's TPS can be configured to work with the stock Honda ecu. There was a guy on TT who sold retrofit kits using genuine Sumitomo electrical connectors to accomplish this. If the Keihin TPS is not connected, it will still work but the stock ignition will default to a 2D map instead of 3D.
Additionally, the Keihin PWK powerjet circuit will have to be disabled due to the inability of the stock Honda ecu to run this circuit. Failure to disable the Keihin powerjet will result in the circuit flowing fuel at all times which will adversely effect your overall jetting. Many guys install a plug, or physically solder the brass Keihin powerjet closed, then reinstall the jet which physically disables the circuit.. There are a lot of details concerning this on TT.
Also be aware that you will require a short body Keihin PWK with TPS to accomplish the 05 CR250 retrofit. These carbs are available on late model YZ's KX's or RM's. The older long body carbs from a 2000 CR250 are too long front to back to fit correctly, and do not have the TPS.

I've retained my TMX with some modified JD Jetting settings. The bike runs very strong and is crisp. The obvious downside is that the TMX is more sensitive to temp/pressure/humidity differences. Most of this can be taken care of with the air screw (I've never paid so much attention to the air screw until I got this bike). I had a top tier tuner tell me (in no uncertain terms) to keep the Mikuni because it produces the best power.

I've found too that getting the RC valve correctly adjusted is essential to making these bikes run well. There's a video on YT where the guy demonstrates what he calls the "HRC method" of adjusting the RC cables/valve. After following it religiously, I'm glad to report it works and makes the bike run much stronger and cleaner.

Good luck. These are great bikes. Most people don't take the time to get the jetting and exhaust valve sorted out, but fi you take the time, they're the equal or better of any period 250.

I liked the TMX better after getting it setup right:

https://www.thumpertalk.com/forums/topic/1191880-carburetor-heresy-i-li…

Quite a bit of the jetting instability with the TMX can be rectified by correcting the stock CR250 squish clearance. Its very large with the stock head and needs to be corrected irrespective of whether you're using the TMX or PWK. Makes both carb options run cleaner and with more jetting stability.
As is mentioned in Erik's TT link, the TMX does produce more peak power than the PWK. The advantage of the PWK is with low/mid, and roll on acceleration performance. The TMX will generate more peak.

I really have to disagree that a Mikuni TMX is a better carb than a Keihin PWK on a cr250.

I've used both carbs on many different cr's and the only place the TMX is better than the PWK is at peak. Everywhere else the PWK beats it, especially down low and into the middle. Not to mention, the PWK is soo much more tunable with it's choice of needles. It's just a way more flexible carb. I would say that 95% of the guys riding those bikes(CR's) would be better off using a PWK, especially if you're riding offroad.

This is comparing a 38mm PWK vs a 38mm TMX carbs. The 38mm TMX-x, actually has larger bore diameter than advertised. They are usually around 39mm--39.8mm. While the 38mm PWK's measure out to around 37.5mm, with the exception consistently being the late model RM250 spec'd carbs measuring out close to 39mm.

great information guys! Thank You!