no power in 4th gear 70cc -CRF's Only Forums

michanic220 · by **michanic220** » Wed Dec 26, 2007 6:04 pm

well, i've been out tuning the carb and the reason being is because first the dirtbike had no power when i got it, it would only wind up in 1st really slowly and then in 2nd and didnt have enough power to shift it into 3rd, well i pulled the carb apart and it looks brand new inside. blew out and soaked all the passages well and put it all back together. still did the same thing, so i took the air filter off and its good alot more balls now, but still lacking a few more horses. i put the air cleaner back on after cleaning it with warm soap and water and go-jo and its doing the same thing, so i took the foam filter completely out of the airbox and put it back together and its STILL doing the same thing?? take it off and it runs fine again, any idea's of what it could be? i adjusted the carb it was to rich so i backed it off a few turns. a messed with the needle adjustment on the throttle and i moved it down and it was boggin cuz it was getting to much fuel, moved it up and it accelurated faster but didnt have no top end still. any idea's of what it could be? the only other thing is, is it smokes like a 2 stroke.. and its a 4.. i think there's a ring going bad, and i think the valves need to be adjusted. anyone know the spec's for a (i think) lifan 72cc 4 speed w/ clutch?

zak13 · by **zak13** » Thu Dec 27, 2007 4:42 am

get a hi flo air filter lke uni or no toil, then rejet, and if youre lookin for sum balls get a new exhaust ot a big bore kit.

ship_killer6666 · by **ship_killer6666** » Thu Dec 27, 2007 10:42 am

zak13 wrote:get a hi flo air filter lke uni or no toil, then rejet, and if youre lookin for sum balls get a new exhaust ot a big bore kit.

??? ? ?? ??? ??? ?????

didn't catch half of what you said

michanic220 · by **michanic220** » Fri Dec 28, 2007 8:29 am

why would i rejet? the jets are fine in it. and what didnt you catch? what he said or what i said? cuz i couldnt have put it any simpler.

michanic220 · by **michanic220** » Mon Jan 07, 2008 8:42 pm

it was as i suspected, the rings were bad in it, stuck like an SOB. i replaced them and it ran great, now it stopped sparking XD soo now i gotta test some stuff.

spaguru · by **spaguru** » Thu Sep 04, 2008 8:42 am

Sell it and buy a REAL honda...

michanic220 · by **michanic220** » Thu Sep 04, 2008 8:47 am

the lifan engine is on the ATV now, i actually like them WAY better then honda's. i've had nothing but problems with honda's. now i have a KTM250 =]

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