I have a 1986 yfm225 moto4 i got on a trade. The motor was stuck so I freed up the piston and honed out the cyl. I think i have it in time but i can not get it to fire. I have good spark, gas. I dont know what else to do to get it to fire. HELP PLEASE!!!!!!!!

 

Takes 3 things to make an engine run: Gas, compression, and spark at the right time. You say you have gas and spark, so that leaves the other 2 qustionable. Double check your timing until you KNOW it's right. Timing can be tricky, and it's easy to have it 180 degrees off. The flywheel has to be in the right position with the piston at top dead center.

 

I have tried it a few times, by that I mean I have turned the motor over with the timing chain off of the timing gear and reset the timing . I have had no luck. The only problem i am having is where to set the timing mark. When you look in to the hole for the timing on the case it looks like this | f | t | I dont know if i set the timing on the t its self or on one of the lines on either side of it?

 

Set it with the "T" showing thru the hole. The T means 'top dead center' and the piston should be at the very top of the cylinder. You can take the sparkplug out and stick a clean screwdriver down the cylinder onto the top of the piston to see exactly where the piston is. The 'F' means "fire", thats when the plug fires off.

 

Where and how do you find the t and f is i cant find it? Like were is the screw.

 

Im not 100% familiar with that model but most Yamahas have an access screw on the top of the left side of the engine down where the crank is. Usually its a large allen wrench to get it out. The T & F are stamped into the top of the magneto/stator assembly that can be seen by looking through the hole were the screw came out of..