im not sure what the problem is w/ my new top end?

[rad blaster]

i had a fresh top end rebuild with a fresh top end and when we broke it in, it was revving kinda sluggish. i rode my blaster for about 20 minutes after the whole break-in process was finished and it seemed to be running fine until i heard what sounded like a backfire through the carb.it ran for a minute after that and bogged out. i tried kicking it over and still wouldnt start. after a couple days i figured id try kicking it again and it actually started again but didnt run for long before bogging out again. the spark plug smelled a little funny after i pulled it out.i checked the reeds to see if the was damaged and reeds are fine. engine also heats up pretty fast and seems really hot after riding. im in need of good advice because im out of options.
thanks-

 

[super noober]

pics of the plug? metal on the plug whe you took it out? what year blasty? premix ratio? more info please

 

['blanshee'man]

Sounds like blow-by to me. Take off your head and see how the piston is sitting, should be snug. It took me over a month and a half to figure this out when i had my top end done, it was doing about the same thing.

 

[L.T.]

I have hurd of this problem before go and check that your head bolt's are torqued right (are tight enuf) and make sure the gasket is not leaking.

that back fire noise you hurd could have been comming from the head...

 

[shawnsadler]

same problem here.. did the break in and now it has no compression i can push the kick lever down easily with my hand... right before it bogged out.. it got really hot.. the plug is greyish black... and it is the stock injector carb and the pump gear is still in good condition.. any ideas?

 

[Cmh156]

same problem here.. did the break in and now it has no compression i can push the kick lever down easily with my hand... right before it bogged out.. it got really hot.. the plug is greyish black... and it is the stock injector carb and the pump gear is still in good condition.. any ideas?

Did you jet it right? And your gear could have failed?

 

[Kennedy_Power]

Check all the basics
Like the reeds are they cracked, broken, not seating flat against the reed cage
Always start with a new plug after a rebuild, with it gaped at .025 inches
If the reed are not flat on the reed cage, then remove the screws and flip the reeds 180 and check it out again holding to a light source