How many rpm's when stock

The average stock "red line" for these chinabuilt wonders is in the 7000 rpm arena.

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If it ain't broke, and you mess with it long enough, it will be.

Keep drilling!

I have successfully drilled the jets on a few of these.

I have also re-tapered the needles with (cringe now!) sandpaper and a cordless drill.

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If it ain't broke, and you mess with it long enough, it will be.

Tim,
I am NOT a 2-stroke expert BUT this is a tuning nightmare. You can sometimes feel 10 degree temp changes.


So is this one



Guess I need to shut up and get out to the garage.

What are most of the guys using for a tach? I bought a tiny tach and it seems to be working ok. It has a 2.5 second delay but you get used to that. I don't think theres any way this ole girl will get another 2000 rpms though. Are you getting 7000 out of a stocker or is that after modifying it? That is what this thread was all about in the first place. I wanted to find out what some of the guys were able to get out of one after it was reasonably tuned.

Thanks
Jack

I have never applied a tach to one of my engines, but loooong ago and far away, the companies selling them stated that the redline was 7300.

Different engines rev to different levels, due to the vast differences in things like how well the ports match up, how closely dialed in the "carb" is, ect. Other things that affect top rpm are weight, type of tires, terrain, air density, ect.

They do rev better once broken in.

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If it ain't broke, and you mess with it long enough, it will be.

I'll take that one off your hands.

__________________
If it ain't broke, and you mess with it long enough, it will be.

125cc and at about 9K it starts to pull. Great fun but I've never had it on a track. The neighbors love it!
Sorry, didn't mean to highjack Drdoesit's post.

On the subject, and FYI, most street 2-strokes can be modded to pull easily over 10K.

Drdoesit, you might check your port timing, at least see that things line up as intended. I think Chinese companies have so many suppliers you can get mismatched parts fairly easily. I have found sheet metal screws right next to machine screws all holding on the same cover and often see mismatched fasteners.

Dave
KC

I have not had the motor apart yet. I also not sure yet if it is fair to compare these little guys with the Japanese built 2 strokes either. And I agree about the fasteners etc. Once I thought that I had blown it for a second and then it went to running again. I got home and pulled the side cover to find a spare woodruff key laying in there that had bounced up and run between the crank gear and the clutch gear. Thankfully it was not the best quality either. The motor runs pretty well all told, cranks right up hot or cold and probably will get 30 mph with 44 tooth rear and my 210 lb self on it. It's only showing 5000 to 5100 on the tiny tach and from the way it sounds it can't do much more. I have had 4 stroke bikes that would turn way over 10,000 rpms too. I am just getting started here and was curious. I appreciate all of the replys and help.

Jack

"I got home and pulled the side cover to find a spare woodruff key laying in there that had bounced up and run between the crank gear and the clutch gear. Thankfully it was not the best quality either."

That was funny.

And true.

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If it ain't broke, and you mess with it long enough, it will be.