China girl 4 cycling

[old motorbike]

My old original 80-66cc still stock with low miles still insists on 4 cycling @ part throttle and cruising. It's better warmed up. Works better at low rpms under load. I moved carb clip to top groove on needle and run 24:1 Do I need a longer needle? Smaller jet? or something else? Different carb?

[Bikeguy Joe]

That's fairly normal. If it breaks in and out of a four cycle when cruising with a light load, it's about perfect for these old school two strokes and perfectly normal.
If it runs at a four cycle all the time when under light load, go to a smaller jet, or solder the one you have closed and re-drill it a little bit smaller.

[Bikeguy Joe]

You can also try opening up the exhaust (cutting the baffle a little) or opening up the air filter cover to allow the ebgine to breath a little more.

[MB-Monkey]

it would also be nice to see the plug chop to see the result. BGJ is right as well a good motor will cruise in and out of the "4cycle"

[old motorbike]

Thanks everyone, I like the jet solder idea. Maybe being at sea level helps cause it more also. For the first mile or so it 4 cycles all the time. Also we've been having 80-90% humidity lately.

[Russell]

What does the term 4 cycilng mean when talking about a two cycle engine?
I recieved my first engine(80/66cc) and I have acouple of questions. First the chain, the rollers have about 1/32 travel side to side. Is this normal, seems that every other chain I've come across the rollers have min side play. Next question, The sleeve casting has a defect. You can see one of the piston sleeve bolts or bolt sleeve due to a air buble in the casting. I do not think it is a problem, but not sure? Thanks Russell

[lordoflightaz]

Originally Posted by Russell

What does the term 4 cycilng mean when talking about a two cycle engine?

I would like to hear 4 cycling, I understand the concept, but just what does it sound like?

[Bikeguy Joe]

In order of asking-

Chain rollers with side play- "normal" for these kits.
Casting error- Usually not a problem, but some sellers will replace the cylinder or kit if you let them know about it.

Now, "4 stroking" or 4 cycling sounds like a rough stacatto or firing every other cycle, as opposed to a smooth ""buzz" of the 2 cycle sound. If your engine four strokes all the time, it's too rich.

When these ancient tech piston ported two strokes are "right on" with their mixture, they will break in and out of the two cycle/four cycle sound at cruise or light load, and break into a clean two cycle "buzz" when you twist the throttle, or start up an incline.

Part of the reason is the crappy carb, and part of it is the "ancient tech piston porting". If you have one that runs in a clean two cycle at cruise, you are getting close to a very lean condition.

[Russell]

Thanks for the help!

Russell

So many projects so little time. If anyone invents a 36 hr day it would be a big help to me!

[Echotraveler]

if you wanna open up the muffler, i could recomend cutting 1/2" off from the staight tube that lets the smoke out off the muffler....the one you can remover on the end of the muffler...cut cut until you feel better or you damage it lol... thats why 1/2"cuts are recomended.