Performance cylinder head rebuilding for import & domestic heads. High performance head porting, polishing, rebuildingPerformance cylinder head rebuilding for import & domestic heads. High performance head porting, polishing, rebuilding

Performance cylinder head rebuilding for import and domestic heads. High performance head porting, polishing, rebuilding

Motorcycle / Quad

Porting the heads on bikes and quads has become a huge and competitive market over the last several years. It is important, as a consumer, to know how to choose the shop to port your head. We have been made aware of several local shops who are charging top dollar to port quad heads and they do not have the equipment to machine valves and seats nor do they own a flow bench. Any person who understands how to manipulate horse power from a cylinder head knows that the first step is a proper valve job.
( For more info on valve jobs, click here.)
Also, anyone who as had any experience with a flow bench knows that every head is different, and without testing, there's no way of knowing whether your porting helped or hurt the head (other than on the dyno or the track when it's too late to change it).
The more air that can go through the head, the more horse power the engine will make. The flow bench is what measures this air flow. There is a formula published by Superflow to calculate the amount of horse power that a given head is theoretically capable of producing. The formula is: H.P. = cfm @ 10" x .43 x # of cylinders. On the multi-valve single cylinder heads such as the Honda 400EX, XR650R, and the Yamaha Raptor we've been seeing gains of around 20 cfm @ 28". This converts to 12 cfm @ 10" which multiplies out to a theoretical 5.1 H.P. increase. Based on the feed back we get from our customers, we feel this is relatively accurate.

32mm Manley oversized intake valves
for the Yamaha Raptor!


Now available exclusively from Louthan Comp; 32mm oversize Manley intake valves for Raptors. Our flow bench has proven that it is beneficial to replace all 3 intakes with the larger valve.

32mm Raptor intake valves... $50ea.

 

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Single Cylinder w/ 2 valves
(each head)

competition valve job $80
port & polish $140
install larger valves (each) $20
port match intake manifold $25

Single Cylinder w/ 4-5 valves

competition valve job $140
port & polish $180
port match intake manifold $50
install larger valves (each) $20
hone valve guides $30

Inline 4 cylinder w/ 2 valves per cylinder

competition valve job $160
basic port & polish $250
port match intake manifold $80
install larger valves (each) $20
competition port job $500

Inline 4 cylinder w/ 4 valves per cylinder

competition valve job $200
basic port & polish $350
port match intake manifold $80
install larger valves (each) $20
competition port job $700

 

Countless hours have been spent developing and testing our head porting techniques on the flow bench. The first Raptor we had in the shop was tested 16 times!

After the initial flow test, the valve seats are cut with 3-angle cutters. Then the bowls and runners are shaped by hand.
The PCD cutter is the latest technology used for surfacing aluminum or to adjust chamber volume when necessary
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LOUTHAN COMPETITION LLC 3728 La Branch St SE Salem, Oregon 97317 (971) 720-9192 ALL RIGHTS RESERVED 2016