message to beginners

  • Thread starter Deleted member 12676
  • Start date
D

Deleted member 12676

Guest
I am a very experienced 2 stroke guy and I have good news and bad news for you.
The good news is that with a few tools and a bit more investment you can have a really good ride.
The bad news is that as is the new Chinese two stroke (48cc and 66cc) is poorly designed and needs some parts machined and some parts replaced.
Things you need to do:
1. Use sandpaper on glass to plane the head surface flat and increase its compression a little bit for more power. Also make your own head gasket out of high temp gasket material for it to seal properly.
2. Drill a bigger hole in the wrist pin for less vibration. Without this the engine will always be unrelible as it will shake loose nuts and bolts. Also a vibrating engine makes it uncomfortable to ride. If it still vibrates too much then you need to drill holes into the crank wheels with a 3/8" carbide bit.
3. Take the screws off of the stator coil and clean off the shellac on those screw head contact areas. That is important because that screw to metal contact is the ground path for the high voltage coil and spark plug. The worse the contact is the weaker the spark will be which reduces engine power.
4. Replace the stock nuts/bolts/studs with a replacement kit from Sick Bike Parts. The stock ones are too buttery and will strip threads and break off. Also apply medium strength thread lock to all threads.
5. Lower the needle in the carburetor to the limit because the stock fuel to air ratio is too rich and will make the engine run rough and with less power. It will also cause plugs to foul and stop sparking. You will also need to buy a micro drill bit set and melt solder into the main jet and then drill it out to a smaller size. The stock main jet hole is too big and makes the engine run rich at full throttle. Also make sure the float stops fuel flow at the correct level which affects the fuel/air ratio.
6. Replace the restrictive stock air filter with a bigger foam one that needs to be oiled with engine oil before installing. This will let the engine breath better for more power. The stock one is too restrictive and causes the fuel/air mixture to be too rich.
7. Replace the stock spark plug with an Iridium one (#7 for moderate climates or #8 for hot climates). This gives a more consistent spark at a lower voltage for smoother more powerful running.
8. Put a fuel filter on the fuel line because the filter inside the gas tank won't filter out the finer particles. Also there's usually trash inside the fuel tank that should be cleaned out before use. If not then that will partially block the filter and limit fuel flow.
9. Once you get these mods done and want the engine to start easier, run smoother, and have better top speed then think about putting a good carburetor on that is fully adjustable with an idle jet as well as a main jet. Also a good aftermarket CDI will help in the same way.
10. Consider removing some of the baffles in the stock muffler for better top speed.
11. The most technical mod you can do is buy a rotary tool with cutting discs and mod the cylinder ports for more power. You can widen the intake and exhaust ports and lower the intake port (or take some off the bottom of the pistons intake skirt) so that it has a bit longer open port duration (120 degrees) which gives it more power all around.

All of these mods are fully explained on my sites pages. Click my signature link and start reading.
 
yes they are built better and are more reliable but you are stuck with them as they come with low power output. To get more power you have to make your own competition camshaft which no one on this forum can do.
For the same RPM a 4 stroke outputs half the horsepower as a 2 stroke because it only has one power stroke every 4 strokes whereas a 2 stroke has one power stroke every 2 strokes.
 
QUOTE
"" Drill a bigger hole in the wrist pin for less vibration ""

You mean length wize, to make the pin lighter in weight what is the wall thickness before & after drilling the pin out ??

That would work .... Got a picture before / after please ??

QUOTE " Replace the stock nuts/bolts/studs with a replacement kit from Sick Bike Parts. "

I replaced most bolts with stainless steel ones, just from the hardware shop on the corner ... Works good .. looks good ...
 
Last edited:
of course it works. I did it myself. It lessens vibration but only partially. the full cure is drilling the crank wheels. all is on my site, including dimensions.

you need to replace the cylinder studs and the frame mounting studs. buy the kit from SBP.
 
Ok i will drill the piston pin out ... That's fun to do ..

I made my own frame mounting, and re tapped the 4 mounting holes with M8 galvanised 8.8 bolts

All other bolts like cylinder struts I used Stainless, looks clean and cheaper then ordering from some company ..

IMG20160806160444.jpg
 
Ok i will drill the piston pin out ... That's fun to do ..

I made my own frame mounting, and re tapped the 4 mounting holes with M8 galvanised 8.8 bolts

All other bolts like cylinder struts I used Stainless, looks clean and cheaper then ordering from some company ..

View attachment 73404
Those are some good looking mounts, I'll tell ya that
 
No need to sell, I give the drawings for free ... Hubclamp & engine mounting

Look up the thread " tinker time " I put the drawing on there, you only need to check the dimensions for tubes and engine mounting

Note that I drilled out the 4 engine mounting holes from M6 holes to M8 tapping ...
 
Here are the drawings, please use them we are here to share and make things CHEAPER ... and we all know cheap is good ...

note the hubclamp is made from PIPE & plate And the inside of that pipe machined to be just a bit bigger then the hub .... note I use 2 m6 nuts between the rear sprocket and that hub bracket for setting the rear sprocket all around the same ... Works perfectly ... It's a pAiN to install though ....

I use 3M tape between all the connection points, strong as bull shat stuff,

Note also that the stock exhaust does not fit with this bracket, so I made a flexible exhaust hose .... The exhaust gasses spray the chain with 2-stroke oil so I do not need to oil my chain any more ....

14705505322991819319526.jpg
IMG20160530131439.jpg
IMG20160331105529.jpg
IMG20160331105537.jpg
 
Back
Top