Help a '98 summit 670 X High Altitude?

[summitguy98]

I have a 670 sled, but replaced the engine with a 670 X. It now doesn't work very well at high altitude. I'm kinda dumb about repairing these things, but I love to ride them, so if anyone has any ideas about how to get this running well again, I would be much appreciated. Is there anything different about the X that I should know? Also it did run pretty good until it ran out of gas. Could it be that something has clogged the fuel delivery system? Like I said, I just don't know. Thanks in advance for any help.

Cody Stocks

 

[thekrust]

There is a possibility that when it ran out of gas the fuel mixture got too lean and burned a piston before it quit. Pull the exhaust and look at the pistons through the ports to see if there is any damage.

 

[BOOFIT]

I swapped a 98x 670 into a 96 670 back in the day.
Did you take the computer and dpm from the x? The older 670's had HAC (high altitude compinsator) When they went to the x in 98 they changed to a dpm system that included a air pump or something under the motor and a dpm rail on the air intake. I believe the timing curve was also different.