atc70 with 125cc dies when put in gear

[sstark82]

[Hi guys, long time since ive posted but I am at a loss. I just got a atc 70 that was converted to a 125cc. Not sure of the make because i cant find any markings. I got it home and was running it but on the higher rpms it would bog down. I figured it needed a carb clean so i took it apart, mikuni carb by the way and ckeaned the jets thoroughly but once i put it all back and installed it, it would idle great then when i would put it in gear. It bogs down and dies. I have filters on the fuel line, tank is clean. Im at a loss now.

[sstark82]

Checked the spark plug and motor is running lean. Main jet is size 100 should i swap it for a larger one or is there a way to adjust the carb to get more fuel to the motor? Anyone??

[3 Wheel Drive]

You might try sending Kasey a PM, he's like the Burt Munro of 3 wheelers! Can you post some pics? Mabey it's a gy6 you have in there... :pics:

[tripledog]

There may be some sort of "neutral safety switch" that is not functioning properly. Such devices are commonly found on motorcycles to kill the motor when the bike is running in neutral and shifted into gear with the kickstand down. Although there is no kickstand on your atc (I hope), if the motor was designed for a 2 wheeler, it may very well have the aforementioned "safety switch" that can be easily bypassed. Just a thought...

[burnoutboy]

hi i have just been through this exact problem with my converted 70. what I had done wrong was I had the wire for the neutral switch running up to the cdi, which would in turn earth the cdi out each time the bike was put into gear. i ended up just removing the switch from the electrical system. problem solved

[Vealmonkey]

You can also check to make sure your clutch is adjusted properly. It also sounds like your main jet may be a little small, like you said. Check your throttle cable adjustmant as well. If too much throttle casble slack, it may not be opening up your carb fast enough.

[sstark82]

dangit the page shut me out and I had a large reply.....

[sstark82]

It was operator error on the engine dying. I was not used to manual since I got spoiled with the auto clutch. But I set the needle valve down all the way and ran it and she improved some. However I cannot get to full throttle without it cutting out again. I adjusted the air fuel mixture and again it improved some but still...no full throttle. I am going to just get a larger main and reset the carb to the original settings and start again. the main is 100 what size would be good to jump to??

[sstark82]

when I ran it the last time, the plug got dark. almost like it was too rich. 194715 These are the only markings I can find on the motor....