Interesting...

[pdxrhett]

I decided to take of the head of my mitsu 49cc and guess what? It has a lot of carbon deposits on the top of the piston... Normal?

Also, I can't get the head to go back on - should it be very hard? I'm not using a ring compressor, should i be? (don't have one )

Rings appear to be OK, and the cylinder wall is in pristine condition (looks new, and it has almost 1500 miles on it :O).

What will make getting the head on easier, and how do I clean up the piston?

 

[Bryan Smith]

I recently pulled the jug on mine and was able to squeeze each ring enough with my fingers to get the cylinder to slide over each, one at a time. Make sure you line up the gap in each ring with the alignment pin in the piston groove. A little carbon is probably OK as long as the spark plug is a brownish color. black on the plug would indicate that it is running a bit rich.

 

[Happy Valley]

What oil mix are you using?

 

[pdxrhett]

30:1, which i will admit is rich in my opinion. my mixture screw is probably set to 50:1

 

[thescooterguy]

if you removed the rings , make sure you didnt put them back on upside down .

 

[thescooterguy]

did you get it back together ?

 

[Mountainman]

naturally a little oil on them rings helps them to slide back down
or I should say slide back up

carbon on that piston thing
almost every engine that I have ever taken apart has some to a lot of carbon
and as we know 2-strokes will have the most

scrape most off forget the rest (carbon)

ride that thing

 

[pdxrhett]

yeah, i got the head back on. turns out the rings weren't lined up with the pin on the piston. but, i rode it for maybe 10 miles and then my engine sprocket dies. it literally bent in half. Jerry, I need a VERY hard sprocket please

 

[thescooterguy]

your drive sproket bent in half . something happened to make it do that . any ideas? sounds like something wasnt lined up . you should switch to the 8mm much stronger , but if the original problem isnt fixed it will break something else . can you bring it by my house in gladstone ?

 

[loquin]

Never heard of a mitsubishi 49cc two stroke... Until very recently, the largest one they made was the TLE43 (43cc.) They just came out with the TLE48 (a 48 cc motor.)

Nor, does the mitsubishi carb even HAVE a mixture screw. There's only an idle adjust screw.

If it's a genuine mitsubishi, it will have a 'two-barrel' carb. One of the 'barrels' is used to send air (only) to the cylinder for a short time, to reduce emissions.

If it's a true mitsubishi, you should be running at 50:1 on the premix.