Which Yr. Cyl. To Send/for Eric

[JWW0846]

I Am Sendind Out My Yz 490 Cylinder & Head To Forward Motion,and I Am Wondering What Yr Would Be Best To Send .
I Have A 1990 Cylinder And A 1986 Any Recomandation On Work To Be Done What Powerband Ect...

I Am A Vet Expert That Rides Alot Of Rough Scrambles,tt And Cross Countrys.

Also Thinking Of Sending Both Cylinders To Have 2 Different Powerbands..

This 490 Motor Has Been Put In A 2001 Yz250 Chassis And I Am Running A Pc Pipe That I Have Modified To Fit Also 39 Pwk Carb..

Can You Guys Also Provide Pipe Dimensions So I Can Have Aircone Make Up Some Cones For Your Porting Mods,if So How Much??????????

Thank You
Jerry Warren

 

[Studboy]

Jerry, as far as the pipe goes, I would try the bimotion software out. It is freeware and you can get it at www.bimotion.go.to

With a few measurements and input from your bike, you can have yourself some pretty good specs.

 

[Eric Gorr]

The 90 cylinder has better transfer ports. You could spend a lot of money building pipes, but I recommend an FMF.