125-200cc Wb165 Jetting, Exhaust, Engine Setup

I rode Curly Fern Enduro, which is Dave's area at sea level with a 178 main. I was WOT in deep sand at times and all I did was turn the AS in a turn from what I was running at 1000-2000 ft at home. Bike ran fine at all throttle openings. My PWK 38 is sleeved to 36.

I'm running a 2002 cylinder with the older port design. I wonder if that might have something to do with it. Anyhoo, I'll be running the Greenbrier this weekend with a big, fat main jet and teeny little pilot jet. Wish me luck!

Have a good ride! I wanted to ride it this year, but all the other guys in my crew decided to pass, as it isn't a WNYOA run. Too far and too much fuel to go alone.

If the Weather Channe's predicted "weekend soaker" comes to fruition, then Greenbrier will be an epic experience.

I will most probably try a 13/48 combo or a 14/50 but do you guys find it necessary to change the chain linkage with different gearing like a 14/52 for example? Or just re-adjust the slack?

14-52 might be too much for the stock length chain. I was running 13-52 and my adjusters were almost all the way in.

13-48 works really good

Anybody running the stock 09 and newer carb?

Yep

Changing more than 1 tooth on the sprockets will be cause for a different chain.

I like the 14/52 gearing as it adds snap off corners. Usually the difference in a 100 and 125 is one tooth on the front (ie. Sachs 100 & 125). Same with the difference in a 125 and 175 of similar design (ie. Yamaha 125 & 175). Same stroke on crank on those engines. Same gearbox.

Who sleeved your PWK ? I had this done years ago on the stock VM38 by Vic Krause on my 1982 Husky XC125 .

Rich Daly at DynoPort sleeved mine.

I had mine sleeved back then to a 35mm.

My bike is a 2008 Cr and the jetting is stock what ever was in it when i received it.Bolted on the 165 kit and did not touch anything.I live at sea level and now have raced it from sea level up to 8,000 feet.
runs great in all areas.I have posted a few videos and you can see or hear the bike runs great.
I raced all the races from motocross to wide open desert with a 14/52 But for last dog standing i ran 13 /52 no problem

I think a few guys here have had Ron Black of RB Designs mod their TMXX carb with excelent results. I am awaiting his work on mine and hope to mount it up in the next few weeks. My current TMXX works pretty well with the TMXX with a 17-61 RM needle, 25 pilot, and 480 main. High elevations but low humidities. I can't wait to try the RB Designs TMXX, as I expect it too make the 165 even better.

I am. I ran the stock CR jetting in my 125 with good results. For the 165 I sent it to RB Designs and have been pretty happy with it. His recomended starting point for jetting the 165 was too lean but I've got it dialed in now.

What were the settings?

Tim,

Just got back from my first ride on the '12 165. The RB Designs carb worked awsome. Very crisp everywhere, instant throttle response and ran great from 4000' to 8000' and back. My jetting is as follows:

RM 16-62 needle in the 4th slot down from the top.
470 main
27.5 pilot
His handy new air speed screw at 1 3/4 turns out
44:1 mix with Amsoil dominator and 100LL avgas(compression is set at 220 PSI)

My new Rekluse core exp couldn't handle the torque....I will try the stiffer springs. Set it so it would "try" to idle in gear and the clutch would slip up to about 4-5 K rpm. Loosen the adjustment until there was only minor slipping under load at low rpms and it would stall without significant throttle below 2K and wouldn't sit still at all in gear without the clutch fully disengaged. This was with their recommended set up. Maybe the stiffer springs will work but I think that this motor just makes to much low rpm torque, hope I am wrong. Had to ride it like a standard clutch all day and it still wants to slip when pulling a gear high under load below 4K rpm. I will post more later.