As stated in the "First Ride" post I had a 13t front sprocket and a 48t rear on the bike when I did that ride. I have been working on making the second of my 86 KX125's run....I'll restate that, run better. Really I tore everything down on the bike, fixed and or maintained any parts that were in need and re-assembled as any good dirt bike guy would do. I did find some extra stuff in the carb that really shouldn't have been in there so I was pretty sure that it was going to run much better then when I brought it home..... Welllll it didn't. That actually surprised me, I was sure that it just needed the carb cleaned out. To fill you in on what it is doing, it just has no get up and go, very little on the bottom end of the power range which is typical for a 125 but it wont pull through the mid range and just starts sputtering and spitting and has nothing on top cause you can't get there. Figured it has to be the carb is clogged up. By the way it has 12t front and 48t rear sprockets. The only other part that I thought might be the problem was the power valve set up. Now it is actuating properly but if the PO disassembled it and didn't get the alignment marks in the right spot it could be an issue. From the outside looking in it seemed fine and was assembled the same as the one on my first restore KX but since I didn't take the valve out only took the cylinder off, something could be wrong.
All this to get to taking the #1 KX for its second ride. I started to question whether I had #1 put together correctly and if it would run good on the top end. I decided to swap the front sprocket to the 12t (I had a new one for it). and give it a run.
WOW! That bike rips! I was very happy to discover that the #1 KX runs really good, It snaps to attention and flat gets to rippin right away. I spent about 10 minutes on the bike just playing around and making some fast runs across the property before putting it away with a big smile on my face. Always nice to know that your long hours in the garage paid off.
So back to #2, that ride put my mind at ease about the power valve being wrong as when you take the covers off of the left side of the cylinder you can see that the valve is in the same position on both bikes. Back to the carb. I decided that maybe there was still gunk stuck in the main jet or the ports that feed the main jet. I tipped the carb on its side and pulled the plug off the bottom then pulled the main jet to have a look. 330 main. Then it hits me, #1 bike has a different size main in it. check the book it says it should be a 370. I pulled the main jet out of #1 bike and sure enough it is a 370. Don't know why I did this but instead of putting the 370 in bike #2 and taking it for a spin just to test it out I went and put it back in #1 and went and ordered a 370 for #2. So in a couple days when the Jet shows up (should have it by the weekend) I will go test it out and let you all know if that fixed it. Hopefully that is the only jet or needle that got changed from stock, the numbers on the rest of those things are soo small I don't think I can read them.