well i need some insight from a techy out there. i had a f2 that i bought and rebuilt the head on twice first time i had a shop do it and when the head fd up i fixed it myself the next time. then that motor blew. i bought a parts bike for a motor that turned out to be an f3 so i did a motor swap which later turned into basically a frame swap. it was running ok until i swap the f2 carbs off it and put the f3 carbs on there and swap the harness and all the works. now it cuts out alot when accelerating and backfires. today whan i put the new sprockets and chain on i had the rear suspended so i let the bike run in gear 1st, then 2nd 3rd then back. i let the bike run for about 10 mins maybe and shut it off and for some reason i checked the header and noticed that 1,3,4 were almost to hot to touch for even a sec and i could grab number 2 and hold it. now i know this means that number two isnt firing which would explain the backfire the extra fuel ignighting but i dont know why number two would be cool while number 3 was hot considering they runn off the same ignigtion coil. you think maybe the wire is bad or maybe the plug? need some help guys

 

it also will not stay in 2nd gear why accelerating jumps to 3rd but will stay if down shifted into 2nd. dont know whats up with that. the manual says bent shift stopper spring but have a friend saying shift fork ideas

 

man that sounds like a nighmare. i would run a compression check on all cylinders. and im assuming the valve shims have not been adjusted to spec. new head gasket maybe. or coils. i would do that as well. not sure about the shifting problems. (brain is fried)

 

well the motor is completely stock i mean like never been cracked head hasnt been off that i know and the cams havent been adjusted. or shimmed except from factory.

 

compression check for sure. but it might be a coil problem. how many miles were on the engine when you pulled it. shims are suppost to be checked and adjusted every 11,000 miles.

 

F3 motor and carbs need a fuel pump at higher rpms

 

Do your basic tune-up and go from there.Whenever i get a motor for what ever i'm working on,a oil change,coolant,new spark plugs,anda new battery can do wonders.But i would change your plugs and check your wires and coil!

 

i believe the motor has 32000 miles not for sure. i also forgot to mention that this started the same time my speedo quit working and the mile guage also quit. idk whats wrong withi it. i went to honda today and picked up a new spark plug wire for number two since i dont think the coil is bad considering that number three cyl is fine.