I have a '88 TRX350D, that hasn't run in awhile...I had some fuel pump problems, fixed those and I got it running, now there's another issue...

The thing runs fairly smoothly for literally about a minute (with a little throttle; doesn't idle very well yet), I hear sort of a click or light scratching sound and within a second it cuts off, no real sputter or anything. In fact it might cut out before I hear the sound it's so close, it could be just the engine turning or something??

The only oddball thing currently on the machine is I have the fuel pump relay jumpered out...

It seems to cut out right when it's getting "warm"...any thoughts?

After a short rest, I can go back out, start it right up (first crank), and it'll run the same...45-60 secs then die.

 

usually if a four stroke motor runs till it starts to warm up then the valves need adjusted. as the engine gets hot and the metal expands in the head it makes the valves stay open and lose compression

 

It's certainly possible the valves need adjusted...I got it dead from a friend...

If this was the problem, would it just cut off, no sputter or anything?

 

yep it gets warm and then just dies