swapping to a 2-smoker kx65 motor

[oscarmayer]

LT80:
The internal gearing was not up to par (trans gearing). Apparently any of the 125 transmissions no mater what you do to them really will only hit around 40-43 mph even at 10k rpm (which we can run to 11,500) the 2 smokers run 14-16k and can hit upwards of 55mph. That was why he would get passed on the straits like he was hitting the brakes. We had the 16-17hp same as the CVTs', but not the rpm's and in the upper R's we loose the torque while the 2-smokers' gain it.

self27:
It is a prototype design biased off a typhoon xtreme style but highly modified.

Thoughts,
If I had ran a 155 gearing It would have hit the same as the CVTs. with this new motor we can hit 60+ and keep going till it blows when done.
it has 6 gears and we will have a 13T front with the same 34t rear, so it will be setup really nice! with 6 gears he should have no problems with the hills. If we need to I can change the front out bigger, or even the rear. (rear currently requires complete rear disassemble due to where current ring gear sits inside swinger, but having a custom swinger made and it will run a raptor 125/250 rear end which will solve that issue)

86T3, not decided if I am going to TF yet, but if I do, this bike could not go. the suspension was specifically designed and build for his weight range, if you say in it, you would destroy the shocks on the first bump. I am building a 180cc one for myself, and that one I will bring to TF for fun. it will hot around mid 50's and let you slide sideways the whole time doing it.

[Toaster556]

Oscar, did you try the XL/CL/SL70 transmission? It runs a 0.96 fourth gear instead of 1.043 found in the chinese transmissions. I did the swap last year on my Zongshen 125, and the difference is noticable.
However, the KX65 with the 82 kit makes a fantastic torquey powerband. It will help your kid for sure. What will you be doing for a pipe?

[oscarmayer]

gonna run the stocker, I found a site that tested every pipe (not custom made) for the kx65 engine available and the stocker appeared to be the best power band of them all on where we needed it. most may smooth it out, but sacrifice lower end, and some lots top end, we needed lower mid through higher end, WOT is not as critical for over all as 2/3-4/3 throttle is where most of the time he rides, so I am setting it up for his riding style. the stock pipe hit hard at that point and dropped flat at the 3/4 mark exactly where I needed it. so it works out and saves me some $$$.

[oscarmayer]

here are the latest photos of the progress.

New radiator was installed, finished engine mounts and their supports, installed harness, installed new XFR nerf bars, finished motor with the Athena 82cc BB kit installed now.

[oscarmayer]

finished it last sat and touched it up Sat. night before Sunday's race.
Let me know what ya think. it runs fast! now the rider just needs to learn to operate the bike. so we will probably spend most of the season this year int he back of the pack, but he will get the hang of it and do better soon.

[SELF27]

looks good. great job.

[oscarmayer]

Thanks, took lots of planning and thinking on how i wanted to make it work all together.

[oscarmayer]

well bike would not run for the race this last weekend, torn into the motor and found the piston had cracked and the ring broke. time to replace piston.

[86T3]

Dang, that sucks. Has your boy been getting used to it more? Any videos?