more top end speed after run in

[4wdingman]

will my 70cc happytime motor gain more top speed after run in cauce i have done 50km and it can only get up to about 40km?? Could it could be cauce i am not getting enough air into the carby?
Thanks

[Bikeguy Joe]

I have had kits that ranged from 25 mph (40 kph) to over 35 mph (60 kph).

A lot depends on the engine, which intake it has, how well the ports are matched, what type of muffler, ect.

Most all of them can be made to run 50-60 kph with a little work.

Break-in does help, but I think a lot of it is due to "tweaking the engine and components" during the break-in period.

[Bikeguy Joe]

How is your mixture? What color is the plug?...that's where I'd start.

[4wdingman]

well i am running 20 to 1 and the plug is a nice brown colour!!

[Bikeguy Joe]

You'll get a little more power and maybe speed if you go to 24 to 1, or even 30-32 to 1 synthetic oil.

How's the break-in going? Has it picked up any speed yet?

[Spunout]

i noticed a big difference in out-of-the-box power, between bushing and bearing motors.

bushing motors were quick from the start, but bearing motors dont achieve total power until you're into the third tank.

its a new motor. everything's tight, and the rings havent seated yet.

[4wdingman]

well when i first got it, it had a bit of power but no top speed so i drilled some holes in the carby filter cover and that made a bit of a different to the top speed but it seems to be not getting enough air.
Like when i ride i can put it full and it will get up too a speed and then the exhaust will make a vibration noise and it just wont go no more.

Thanks

[Dave31]

Have you checked your motor mounts? It is possible the fuel is foaming in the carb due to lose mounts or excess vibration.

[4wdingman]

well I have rubber between the frame and the mounts,and it is a smooth to ride.

Thanks

[Bikeguy Joe]

Sound like it is going into a four cycle when it "gets there". Try a leaner carb setting. (one notch up on the needle.)