Lacking Top End Power

[DaveenBavari]

I have ano 80cc bike and my problem is that the bike can't rev any higher than 6300 rpm. When I'm driving it feels like it still has more left to go. When I get to 6300 rpm the bike slows down.

 

[6blueoval9]

The port timing on these motors only allow up to so many rpm's...6000rpm is about average on the motors without some port timing modifications and some upgrades.

 

[crassius]

it also depends on rider weight and rear sprocket size - what are those and what speed are you getting?

 

[Street Ryderz]

The port timing on these motors only allow up to so many rpm's...6000rpm is about average on the motors without some port timing modifications and some upgrades.

Hell no that makes no sence at all. A stock engine can hit 10,000 rpm just by changing the pipe and a stock engine on the stock gearing and 26" wheel is spinning 8,300 at 35mph.Many stock engines are hitting 40 mph now adays add a good pipe and it's possible to hit 45 mph.The sweet spot on most of these engines is around 5,700-6,000 rpm that's where the engines balence resonates the least and feels the smothest if burning cleanly and can run for extended periods at that rpm so 6,000 really is a good cruising speed not a top speed.My street gearing allows me to cruise at 6,000 rpm and be doing 47-48 mph perfect for long distances.

 

[6blueoval9]

I mentioned transfer port and mods in general..Appreciate the info on the sweet spot.