Thread: My head just came in
03-14-2007, 02:38 PM #1
My head just came in
Just wanted to share a few pics with you guys.
This is the Franco Dettori Rotax Racing "B" Kit head with CNC ported intake ports and i had Mark Underwood work his magic on the exhaust ports. Super nice work Mark. THANK YOU very much!
Now its time to start assembling the engine for my GPRXP
03-14-2007, 02:41 PM #2
Great machine work. This ski should fly, literally.
03-14-2007, 04:05 PM #3
I need one. Damn those ports are huge! Thats gonna flow some CFM! High rpm high boost guys are gonna love those babies. What cc are those exhaust ports now?,,,and how much boost with retard on the timing? That stock manifold is gonna melt. I`m getting a new building (FINALLY) around the corner. It`ll be a while before a header deal is ready. Stock manifolds are gonna fail with the excessive timing retard. You`ll have a flame all the way through the exhaust fan.
03-14-2007, 04:18 PM #4
I don't know what this baby is gonna flow, but it'll flow good. I do know that my Nils head will flow 345 CFM's
Wish i had time to get this one flowed, but its going straight on the block and into the GPRXP hull
03-14-2007, 04:21 PM #5
That is an excellent port job.
Were templates made up, or was this done completely by (free)hand? Would be interesting to see before and after flow data. I bet Mark's hands are killing him after this.
Last edited by jimboman; 03-14-2007 at 04:23 PM.
03-14-2007, 04:27 PM #6
Actually, the intake ports are CNC ported at RR in Austria. Franco Dettori doesn't touch the exhaust side because he said the head makes too much power as is
Mark talked me into letting him port out the exhaust and im glad i did. Marks freehand port work is top notch
The intake valves are 4 grams lighter than stock and the exhaust valves are 7.5 grams lighter than stock. The lightweight retainers also save me 6.5 grams each. all the weight savings add up to 9000 rpm all day long.
03-14-2007, 04:34 PM #7
- Join Date
- Dec 2006
- Crest Hill, IL
You gonna make sweet luuuuuuuuuuvvvvvvvv to that head tonight?
03-14-2007, 04:36 PM #8
No, but my torque wrench is
i have already fingered the ports though
03-14-2007, 04:38 PM #9
03-14-2007, 04:39 PM #10
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