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Pwk carb on xr200r

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Ok so in Chad's post, Chuck, you were talking about the pwk carb and needing to do some fab work. Would that be to mount the pwk to stock intake and airbox boot? 

You said it would take a lot of work on the jetting. If I decided to give the pwk a try in the future, how would I go about finding the right jetting? I live in the Oklahoma City area, elevation is around 1200', Temps go as high in the summer to 110 (which I don't even like riding on the street in those temps so I doubt I'd ride dirt), and down to single digits in the winter. We usually like the days that start in the 40's and get up to high 50's or 60's. 

Daniel 

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The PWK info is growing but is spread over several threads in two forums. Do a search in the 230 forum too and be prepared for some reading. Im never sure which thread to post new info into? After the idea matures I hope we can create a sticky with info pulled from all the threads.

The 230 guys have a jetting baseline that should be a good starting point for the 200

Main jet 135

Pilot 35

JJL needle

2.0 slide

Short needle jet

 

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I don't know how a PWK would work on a stock 200 because the carb is 16% larger than the stock pd carb. A 218 engine like I have is 12% larger than a 200 and only 5cc short of a CRF230F.

PD carb has a flow area equivalent to a 26mm carb, a PWK is 28mm. And a PD carb works better on a 218 than on a stock engine, probably has to do with the increase in air flow thru the carb.
XR200=195cc, 218=218cc, CRF230=223cc. 

The good news is the PWK seems to provide better and smoother throttle response than the PD series carbs.

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On 6/14/2017 at 0:25 AM, woodsryder said:

The PWK info is growing but is spread over several threads in two forums. Do a search in the 230 forum too and be prepared for some reading. Im never sure which thread to post new info into? After the idea matures I hope we can create a sticky with info pulled from all the threads.

The 230 guys have a jetting baseline that should be a good starting point for the 200

Main jet 135

Pilot 35

JJL needle

2.0 slide

Short needle jet

 

That is the jetting I started with but the engine was way too rich, and 35 Pilot is the smallest available.  I don't know if my experience applies to a stock engine as mine is a Powroll 218 with 11:1 CR, a Torque cam, plus XRsOnly stepped header.

I tried different needle clip positions and #1 it was still too rich at half throttle, noticeable when reducing throttle from WOT and the engine would blubber at 1/2 throttle. But also seemed lean at 1/4 throttle, and rich below. :banghead:  
I tried opening up the exhaust and had very good improvement at low speeds, so  I substituted a "Power Ring" piece for the muffler insert and that provided a big improvement at low speeds.   A bit more noise but well worth the change in power for my riding area. 

Next I tried a #3 slide and 38P, a tall needle jet, and #2 clip position; engine ran better but air screw was too far out so I installed a #40 pilot. 

Still too rich even when changing to #1 clip position. Tried a XR200 needle and that helped bottom end but the engine seemed lean and was running hotter than normal. 

Next I tried a N68A needle at #3 clip position, which is the same as a JJH but is multi taper with the first taper at 1 degree, then a 3 degree taper to the end. Multi tapers are common on 4Ts and lean  1/2 throttle.  Available from JetsRUs. Air screw is 1 7/8 out so maybe could try a 38P.   Engine ran much better on the ride today, pulls good from idle in 2nd or 3rd, has smoother throttle response, etc.  Restarts were usually one kick but sometimes I needed to kick over at WOT.  Tip over flood clears were only a few kicks at WOT. Engine ran cooler than with the tall needle jet. And it pulled strong, and fast,  to 10k in 2nd and 3rd gears.  

I rode a lot of tight gnarly ST and never needed 1st gear as the engine will pull the bike up any hill or tree root from idle in second (I set mine at 1600-1700rpm), and that included tight climbing switchbacks. The soil moisture provided good traction but throttle response was so good that wheel slip was an issue, as was front wheel lift when exiting switchbacks.  I got frisky and decided to climb an 8 foot cut bank with a one bike length running start using 2nd instead of 1st. Piece of cake, it scampered up like my Trials bike.  :ride:

I'll do some more tuning but I expect the changes to be minor.  I really do like this PWK carb. 

Edited by Chuck.
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