need help...backfires, lacks in power

Is this a 2-stroke or 4 ??

Either way, it sounds like a fuel problem......which is about the only thing that you did NOT mention; is there a reason that you ruled that out ??

A good dose of carb cleaner (Original Gumout or Berryman's B12) might help.

Have you drained the carb. bowls and fuel tank and put in fresh gas yet. That might be a good place to start.
 
I am not familiar with that bike, but it dose sound like a fuel problem. If the carbs are cv carbs, with rubber diaphragms, do not use spray carb cleaner. Also if you remove and clean the carbs don't get any carb cleaner on the diaphragms. It will destroy the diaphragms. They are expensive. That is if they are available.
 
the bike is a single-carb 4 stroke, the carb has been cleaned and the tank and carb all have fresh fuel, not sure if the float is properly adjusted in the carb, i'll look in my manual to see how to check the float
 
OK, after that, a vacume leak between carb and engine or within the carb itself. Just because it was cleaned and re-assembled, doesn't mean that it was done "right".

Trying to run it with a little more (or less) choke might give you a clue too.
Assuming it has a conventional butterfly choke, that is.
 
Learn from my mistake.... don't use high octane. The compression isn't high enough to burn it. I experienced the same problems while using 93 octane. Once I started using regular 87, bike worked great
 
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