2005 trx400ex

[jarilad55]

I put a new piston and top end in my 400 ex due to no compression unfortunately it wont start and run I saw a thread from last year that had the same problem but there wasn't any word as to if or how they got it running before it quit it made a loud pop and died I was able tonget it going again drove it about 1/4 of a mile it popped again and died that's when I put it in the shop and started checking it out the cam was in bad shape and the piston was fried. Ive checked and rechecked the valve clearance and the timing is as close as I can get it. I did replace the coil. Any help would be appreciated

[jarilad55]

:muscle:
I put a new piston and top end in my 400 ex due to no compression unfortunately it wont start and run I saw a thread from last year that had the same problem but there wasn't any word as to if or how they got it running before it quit it made a loud pop and died I was able tonget it going again drove it about 1/4 of a mile it popped again and died that's when I put it in the shop and started checking it out the cam was in bad shape and the piston was fried. Ive checked and rechecked the valve clearance and the timing is as close as I can get it. I did replace the coil. Any help would be appreciated

Well you wont believe it I don't after replacing everything except the kitchen sink a exco-worker recommend I remove the decompression gadget from off the cam and it fired so quick I couldn't get my thumb away from the starter button quick enough! So if you do a rebuild remove that thing from the cam and throw it as far as you can. I replaced a lot of stuff I didn't need to but at least I have plenty of extra parts now.:muscle:

[Blodg]

Thanks for letting everyone know what you found, with aftermarket cams there is no compression release so I would have never thought of that.