440 racer

[lancelarue]

Modified a set of domes for the kid for his 2006' 440 racer to run av gas 100. Cross country only, no sno cross. Some long WFO pulls 80 to 95 mph +-.
This will be running on the pump gas timing ie : low compression timing parameters.
Anybody been here?
I have zip experience with these little motors.

 

[milehighassassin]

What are you asking exactly?

 

[lancelarue]

Looking for someone who has run cross country with these parameters and what compression they ran etc. I'm going to try 14.8 to 1 with the pump gas timing and work my way down from there. I'm trying to build a little more torque but leary of the long pulls squeezing this hard. Probably will pull some timing out of it in the testing to find the sweet spot. I just don't know what this motor will stand?????
Will be run @ sea level.
Thanks

 

[treemagnet03]

Some of that will depend on what motor/sled it is exactly...

 

[lancelarue]

Can't believe I didn't say what it was !
2006 Ski-doo MXZX 440 racer

 

[lancelarue]

Heads work good. AV gas is different to read plugs for sure as many people have said.
On a different note, these race 440's run a lot of pipe pressure. I'm sure snocross / corner to corner is the reason. Kid put a new top end on for the next cross country race and I took a look at the bottom side of piston crowns, burnt black oil etc. I had to drop pipe pressure over 3/4 of a pound to get it where everything else is running! ( actually .9 ) Runs a lot better. Pulls hard bottom all the way up.

 

[lancelarue]

Geez, what a finicky sucker! Going from 860 big bores to a 440 is a "mind warp". I had to turn my " clutching hat" 180* around and start over . What a challenge. Went with the smallest helix I could come up with in the Paragon, a 54X50 and a cutler black / white spring. Didn't get it perfect, still making a little heat on the wfo pulls high speed, but the kid says it rips.
Interesting what the ramp profiles have to be when your torque curves are this narrow.
Complete oposite of what I'm used to. Even though I know there's more to be had there, I'm limited to what parts I have and it's still faster then the best setup I came up with using the stock old Team driven or even a Team tied. Hard to slow the shift down enough on the top end to match the little motor. What a hoot!!!!!