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rmz ported head

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I just finished the flow bench development on the 2011 rmz 450 head it turned out very well the intake required considerable reshaping and filling .Any body going in on this head and removing metal thinking there going to make a super head is dead wrong its very good as stock and can be screwed up very eazly i know of an example that made less hp than a stock bike .

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Had mine done by Pro1RacingHeads out of Phoenix. Machines his own non-beryllium valve seats out of Mold Star 90 stock and valve guides from a nickle-bronze alloy. He doesn't cut the valve seat but uses a Haas machine to profile them. He does porting and verifies his work with a flow bench.

Haven't noticed much change on the bottom end but did not loose anything. Head starts to shine mid-range and above!

http://pro1racingheads.com/Pro1RacingHeads/Home.html

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the copper aloy seats you are using is mold star 90 from performance alloys in german town wisconsin i found it back in 2002 and the company ran with it its now used in motorcycles nascar and drag racing.the reason you did not see a gain in low end is because the port velocity is low removing any metal with out gaining huge flow numbers would lessen the velocity on this head reducing some areas in the port and getting a nice flow gain will raise the velocitys to a more acceptable levell for an mx bike widening the power curve instead of creating a hit that makes the bike harder to ride.pro 1 uses a high tech newen cotour seat machine to machine there seats a tool bit machines the seat instead of a form cutter that more less tears the metal both ways are aceptable methods for cutting seats the machinist is still the controling factor in the quality of the seat.

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Ron and I talked about Short Block Charlie's (the guys behind Pro1) using moldstar 90 years ago. Not sure how they ran into the material.. .But Ron knew about this material for valve seats many years ago. I think Delwest was using it a long time ago...

Why is it not used for valve guides? Does it have a high coefficient of friction (not very slick)?

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it is used for valve guides i mades guides for the xr 750 harleys it was the only thing that held up well with valves that had the stems casidium coated the mold star guides would be the ultimate guide for a turbo aplication some of the car and bike road race teams use it in there engines for guides.

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I talked about Short Block Charlie's (the guys behind Pro1) using moldstar 90 years ago.

Wow, you must be about 130 years old :thumbsup:

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Hi Ron

Have you ever done any work on a 2010 RMZ250? Is it worthwhile getting intake and exhaust ports cleaned up?

Thanks.

The 2010 RMZ 250 head is probably one of the best production heads to date from a flow perspective. It is also well sized for an OEM head, although it is a tad on the large side.

This is the first head we have hit over 200cfm with in mod form - but it is at expense of a little extra port size.

Like Ron did on the 450 head - this head can also be made smaller - with small improvements in flow for a more midrange potent engine.

The OE camshafts are also quite aggressive for this year...its quite a bike...

RMZStkvsMod.jpg

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