New engine

[Bozeman55]

Hey all, I've got a few things that are going on with my engine, hope you all could bring some clarity to this.

Just built the bike, have about 50 miles on it. The power is super underwhelming, but they say in the manual that after the break in period, the engine will get a significant power boost. How accurate is this from your experiences?

Something weird also happens when i forget to turn on the gas. Just before all the gas in the line is used up, the thing lurches forward like a motherf***er. Do I have a bad gas/ air ratio? Does the same thing when I start it, slowly loses power as I keep riding. It won't rev up all the way (not even close) unless it's just been started. Am I running too much oil or is my carb tuned poorly? Currently running 20:1 for break-in.

Any and all help would be appreciated. Thanks guys

 

[Frogslayer]

What kind of new engine we taking about?

 

[Bozeman55]

What kind of new engine we taking about?

Engine is an 80cc, "A 80 bicicle kit?" Doesn't show a manufacturer oddly enough, cheapest China engine one can buy

 

[danlandberg]

If I forget to turn the gas on it does the same thing, lean condition, revs up before it's out of gas.
My PK 80 has no bottom end power (40mm stroke) but now it's running better after break in (mid to top end power).

 

[Bozeman55]

Check your float height it should be 21mm the gasket. What your describing is a bad A/F mixture ratio from being too rich.

Your lack of power is caused by incomplete combustion due to lack of float valve regulation Turning the petcock off or slightly open will meter it to a narrow range but it will still act poor.

That lurching you feel will be near the true power it can give when its dialed in. Reminder always wear a helmet please!

Awesome, thanks! How would one go about that? I'm sure there are videos online, is this something I can do with minimal tools?

 

[Bozeman55]

Thank you all for the responses. This community is truly awesome!

 

[Bozeman55]

Yes you just need a Phillips or a small Flathead for two screws and preferably needle nose pliers so you don't have to bend your float with fingers.

Thank you!

 

[Bozeman55]

So I've officially pit 75 miles on the bike, I did nothing to it and it just holds 20 mph comfortably out of nowhere! Used to hold 15 and no more

 

[CrazyDan]

Is it geared to climb mountains? 20 mph is still a bit slow compared to most stock builds. I would understand if it's geared to offroad with inclines.

 

[Bozeman55]

Is it geared to climb mountains? 20 mph is still a bit slow compared to most stock builds. I would understand if it's geared to offroad with inclines.

No, no special gearing. Just the standard sprocket. I adjusted the carb today, revs much higher (sounds normal) but after it heats up it needs to cool again before it will rev high. Every time I ride it this gets better, today it held 20 mph without my pedal assist. Maybe it just needs more miles?