I got this trx250x from a friend for $300 bucks its an 87 i get it home and start taking it apart too see what was wrong with i.let me put a list of things that was wrong and what i replaced beside that.

Piston was melted more or less looked like a horse shoe.Installed a new wesco piston

Cylinder was cracked.Got a nice used one off ebay and put that on

head with valves were melted or broke.Again i got a nice used one of ebay with good springs and valves.

the cam had 1/8 grooves in it.Got a new one and put it on

rockers had just as bad of grooves.Got a used 300ex valve cover with good rockers and put that on.

After all of these fixes it will not start i have gone threw everything i could too fix it set timing valves the whole nine yards and it wont fire up.I got lots of spark and its getting gas.One thing that does seem strange is it seems too be sucking air threw the muffler and pushing it out the carb.I thought i had the cam in backwards but that didnt help so im open too any help that can be given.

 

If that's the case, well then it sounds like you messed up the kick start & are turning the engine over in reverse. Try pull starting it behind another atv. If it starts that way, you know you goofed with the kick starter.

 

I tryed pull starting it already and it wont start.I made sure the engine turned in the right derection when i kick it and it is.I may have figured out the problem.Ill post if im right.Im kind of hoping im not right cuase ill look like an idiot if this fixes it.

 

I had a similer problem when I re-did my top end. Put it all back together and it would not start, had fuel and spark. It ended up being my fault. When I installed the cam I had it 180* off. SO after I fixed that it fired up after a few kicks. Also with the new wiseco 12:1 piston and rings it felt low on compression for the first start, I thought the rings wernt sealing. After I ran it hard during the break in its a bitch to kick over now. So my advise is to double check everything. Good luck

 

I still didnt get it running.I thought i might of put the piston in backwards but that wasnt it.I checked the timing like 5 times already.There is something else i find strange when i set the gap on the valves the left 2 valves have no play even with the screw the whole way up the one on the right has lots of room to work with.Im thinking it must be a valve problem but i cant pin point it too anything.Also my cam has one line on the front and 2 lines on the back of the sprocket am i suppose too set the timing with the 2 lines on the back or the single line on the front?I set it with the front line like i do with most other atvs.Any help at all would be great

Thanks

 

Let me look in my manual and see what it says about setting the cam. I cant remember of my head about the marks on the sproket. Its been almost a year sence I did my top end.

 

Thanks for looking.I have worked on a lot of atvs and this one is by far the toughest case i have had too crack.

 

Let me know if you can read the text and if the pics are clear. All the info you need on setting the cam up. I can send you full size pics if you want.

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