Hey yeah I am still here, just been a busy the last few months.
Basicaly I broke 3rd gear in my 140cc and had to strip it all down and to replace the broken part, at that point I decided to start buying up parts to try and make it into a budget mini motard weapon, with some reasonably priced parts form akuna 6.9mm cam, 30 & 26mm valves , better springs, high velocity porting etc.
I am still trying to find out a lot more information regarding my build, like whether its is worth upgrading the bearings?, best type of metal to use for the valve seats? (to match head expansion rates) and so on. I really cant afford to have any failures and I have to get it right the first time. But that is currently on the back burner as I have just found out that they might not even race a 140cc class up here yet... So I might even end up taking it out to a 160cc for dirt work.
I haven't even had a ride in a few months (apart from a quick go on a friends ttr250 and his daughters ttr125) and I have been dying to get mine going. I have pulled apart my old 125cc expecting to find a broken 3rd gear and to my surprise, I have just bent the selector fork and worn off the tab on that side. After a little bit of applied heat and attitude adjustment with a large hammer, the fork is now straight and I have also welded on and shaped a new tab. even though It is now straight the tabs on that gear were not meshing as well as they should have been and I think this might have been half the reason the problem occurred in the first place. So I filed the little brass washer between the gears and then dished the outer washer a bit more to take up any excess play. It all seems to mesh very well now and hopefully wont give me any more problems in the near future. The motor used to slip out of gear all of the time mainly around third gear and I have also rounded of the star shaped sprocket that attaches to the shifter drum and I now seems to shift very nicely in between gears with little effort and more importantly with no false neutrals. But see how it goes when it is running.
As I have a clone rotor kit for my other motor, So I have put the magneto and backing plate of my 140 on too (just fits with no modifications) and advanced the timing 3mm, It is only a few grams lighter but it looks like a much better unit. Finally I am currently fixing up my first dodgy attempt at porting, now that I have the right tools for the job. It is only a small valve head but it now has got a very nice looking ports, with a much improved radius to the short side on the intake. I will have now have to get a spring made up for the spring seats, to help distribute some load and while I am at the machinists, I am going to see if it would be possible to fit the larger valves form my 140 and get a multi angle cut for a reasonable price, to make better use of my nice porting effort.
But yeah I am still here, just been on a bit of a steep learning curve for an armature like myself. But I am slowly getting there and also learning a lot at the same time.
Cheers Matt
. But like many I seem to learn more when I can get my hands on something, rather than just reading about it.
