125-200cc Part 2: Installation of the WB165 Kit

Next, you will attach the upper engine mount. There are 3 bolts and the mounting brackets go in a particular orientation.

Now, attach the back PV cover to the cylinder. It slides over the oring that you installed earlier. It attaches with 1 bolt as shown.



Next, the upper PV linkage is attached. Here is the orientation of the parts. When tightening the bolt, it helps to use a wrench/pliers to hold the outer spring tab (to prevent rotation).

Next, attach the plastic link arm to the upper post. Then, attach the lower link to the shaft. It also helps to use a wrench/pliers to hold the link when tightening the bolt.

TIP: DON’T FORGET TO INSTALL THE COVER GASKET BEFORE ATTACHING THE LOWER LINK.
I made this mistake and had to disassembly to put the gasket back on… oops!

Here is a picture of the PV linkage after mounting. The upper link should be in a downward position (closed). An arrow is shown in the picture how the link moves during PV opening.



Now, install the PV cover with the 3 bolts shown.

Next, attach the lower radiator hose and spark plug.

IMPORTANT:
Don't forget to add coolant when you are finished installing all the parts. It is easy to make this mistake when letting anticipation get the better of you.

Finally, bolt on your exhaust pipe and silencer. And all of the other goodies like gas tank, side panels, and seat.

I temporarily installed my CR125 FMF Fatty pipe and left the PV cover off (from previous step above). I wanted to make sure the PV was operating correctly after starting my bike.

Initial Break-In:
I am using Walt’s suggestions for initial break-in:

1) Start it and let it idle for ~10 minutes. Vary the rpms slightly throughout. Let it cool completely.

2) Repeat with slightly more variance of the throttle for ~10 minutes. Let it cool completely.
Matt’s comment: During this heat cycle, I checked to see if my PV was starting to open properly. I didn’t get stupid with WFO throttle… just enough rpm to see the linkage move to begin opening the PV.

3) Now go for a gentle ride keeping the engine rpms below the power valve opening ~10-15 minutes. Let it cool and then take a compression test. Note: engine should be warm with taking the compression test. This will be your base line for top end health.

4) Now go ride but try to keep away from extended WOT runs for the first 30-60 minutes. It would good to do a throttle chop plug check at some point early in this ride to verify your jetting.

Here is my compression test (done after Step #3):

I ran my bike briefly until engine was warm.
Installed my Craftsmen compression tester with 14mm long attachment.
Using WFO throttle with 10 strong kicks.

1st trial = 195 psi
2nd trial = 180 psi
3rd trial = 185 psi

NOTE: Later, I will test it again after my first “real” ride (step #4 from above).


Here is a comparison between 14mm long and 14mm short attachments. The 14mm long has equal length to spark plug and was used for my tests.

Here are pictures of my compression test results:

Other Goodies:
After my break-in heat cycles, I mounted up my KTM 200SX FMF Fatty pipe that Walt built for me. My bike is a 2008 CR125 frame, so Walt had to cut & weld brackets for my mounting location.

Also, I’m using a KTM junction coupling for a better seal. The Husky coupling leaks too much.

She’s ready to ride…

An very special thanks goes out to Walt (Wallybean). I appreciate all of the effort that you put into the WB165 Kit. My bike has been transformed into a fantastic woods weapon!

Here is my compression test (done after Step #4):

I did my first real ride (approx. 2 hrs) and used the full throttle range. After I got back home, I ran another compression test to compare with my prior results.

I used the same procedure as last time...
I ran my bike briefly until engine was warm.
Installed my Craftsmen compression tester with 14mm long attachment.
Using WFO throttle with 10 strong kicks.

1st trial = 195 psi
2nd trial = 195 psi
3rd trial = 188 psi

{reserved for future post}

Well, this concludes the installation process that I used. I think it would be great if some of our 2-stroke gurus could share their tips/tricks below. I'm sure there are areas where things are done differently. Let's make this thread a collection of "how-to" instructions for installation of the top end.