Trailfire rebuild

stinger440 · Post by **stinger440** » Sun Jan 06, 2008 5:52 pm

A first for me. I completely tore down a 79 or 80 440 kaw out of a trailfire yesterday. I have never gone further then the top end before. the case cracked so I replaced both seals,pistons,rings,piston bearings. My question is, after I got the motor back together it turned over smooth. I lubed up the cylinder walls with a little 2 cycle oil just to make sure. When I put the plugs in and put it back in the sled it pulls over extremely hard. Like break your arm hard. It fired right up and seemed to run well. Just curious what the compression should be on a fresh rebuild like that? Thanks

JDT · Post by **JDT** » Sun Jan 06, 2008 6:05 pm

165 would be something to brag about. 145-150 would be good however. And of course within 3-5 lbs side to side would be a plus. What carcked the old case? water froze in it?
Todd

stinger440 · Post by **stinger440** » Sun Jan 06, 2008 6:59 pm

I would bet its above 150. My ccw is 150 and doesn't pull that hard. Not sure what cracked the case. It cracked vertically about 1" in from the fan shroud. This was a friends sled and it has been a rattle trap since he got it. So I think bolts got loose and vibration caused it.