1988 Yamaha YFM100 Champ Won't Start

[MakeMyBoysProud86]

I have a 1988 Yamaha Yfm100 Champ that I'm trying to get running for my 3 boys to ride. So far I have replaced the cdi, ignition coil, spark plug, ignition switch, battery, carburetor and the stator. The starter engages but it won't turn over. I'm getting fuel into the carb bowl, I have spark and I believe it has compression. Any ideas what I can do next to get it to turn over and run? Thanks

[Mech]

Hi. I'm in New Zealand and we have different models here, or different names anyway... This is a fourstroke huh ? A little quad.. And an auto clutch ? So no push start..

So the motor does turn ? It's not seized... And the battery is charged and got good power ? You could try using jumper leads and feeding power straight to the starter.. That might get the starter to work.. If not... some of those small starters they use on bikes wear out their brushes in the starter pretty regular. Or if it had been dunked the brushes could be stuck in their holders.

Not starting could be that it's not sucking the fuel in, which could be an air leak on the inlet, or a blocked exhaust which can stop them sucking.. Here in nz we have something called mason bees which build mud nests in holes like exhausts.. Sometimes the little buggers crawl six inches or more up the exhaust and block it up. You could try poking a wire up there and screwing it around, or take the exhaust off at the front and try starting it.  Once you get the starter to work you could try putting a little fuel down the spakplug hole and seeing if it will fire at least once.

Also.. how long since it last went? Did it get shut down or stop running while being ridden..