Motorcycle Racing Forum

Racing Discussion => Rules and Regs => Topic started by: sv303 on January 02, 2005, 04:33:23 PM

Title: Cylinder head machining?
Post by: sv303 on January 02, 2005, 04:33:23 PM
I'm going to be racing supersport next session. Since the motor is disassembled I was thinking of machining the cylinder heads.  In the rule book page 33  6.1.2E.(3)  It states "original equipment head, valves, and cams must remain as produced, with the exception of machining the gasket surface of the cylinder head.  

My questions are why do they let you do this and stay SS legal?  

What other advantages are there other than bringing up the compression ratio, more H.P. in the motor?

What are some disadvantges?    (Need to run race fuel?)
Title: Re: Cylinder head machining?
Post by: Rick Beggs on January 02, 2005, 06:33:04 PM
the main advantage is not having to tear down an engine to verify that it has not been done
there is no disadvantage to this rule that i can see.
it makes maintenance cleanup legal, and hardly anybody wins a race by 2 horsepower, and you may have to run high octane fuel
Title: Re: Cylinder head machining?
Post by: Woofentino Pugrossi on January 02, 2005, 08:58:30 PM
Only reason to maching the heads gasket surface is if the head is slightly warpped.
Title: Re: Cylinder head machining?
Post by: BC61 on January 08, 2005, 09:19:58 PM
QuoteOnly reason to maching the heads gasket surface is if the head is slightly warpped.

not really, a proper valve job usually requires milling the head to maintain compression that would otherwise be lost to deeper seats.
Title: Re: Cylinder head machining?
Post by: Super Dave on January 10, 2005, 07:29:18 PM
QuoteWhat are some disadvantges?    (Need to run race fuel?)

You will need to adjust the cam timing to keep it the same as it was before machining the cylinder head.

I think my cylinder head it cut on my motor, and I can still run 87 octane fuel no problem.  600's don't have a whole lot of space to worry about.  It's not like it's a big twin or anything.  That might give you grief...a twin size cylinder moving at 14k...