Head milling

[rickj]

Anyone know how much a FZR600 head can be milled using stock pistons? Cc's before and after?

Thanks,
Rick

[Tunersricebowl]

A better idea is to mill the block to get the pistons closer to the bottom of the head.Back in the day I used to prep tons of fizzers,the "squish" on those engines was way too large.You should whack on the top of the block untill the piston misses the head by around .030 in. including the thickness of the gasket.
Be sure the machine shop that does the work can duplicate the smooth,shiney surface finish that the block came from the factory with.
I have run much tighter than .030,but I don't advocate that tight in advice forums.

[rickj]

So if I have .030" piston to bead clearance I don't have to worry about valves being smacked, correct?
What's the best way to measure piston to head clearance?

[Zac]

Piston clearance measurement:

A blob of Play-doh on the piston (at the valve pockets), assemble the engine, turn the crank a couple times, pull the head and measure the play-doh thickness at the thinest section.  A little oil on the vavles and piston will help keep it from sticking.

-z.

[Tunersricebowl]

This type of modification is probably best overseen by someone who has done it before or better yet the guy that is going to do the milling of the cyls. I'm not saying that you could not do it,but you should be reading the "how to" from any one of a number of hot rod engine books. This type of performance
mod can be found in car engine books. You should read up on it a little and then dive in.By the way the car engine's piston clearance numbers should be ignored by cycle engine tinkerers.

[251am]

 Hey guys, is this stuff legal to do to our race bikes? I have yet to dig deep enough into the regs on this stuff as I'm just starting out, and motor mods are last on my list of to dos. I remember one of the Hayden clan getting penalized last year for de-burring valve pockets. AMA and CCS are not the same, but how far can we go with mods?

[Tunersricebowl]

Depends what class you are running. Superbike or FX, metal removal is allowed. I think AMA supersport allows milling as well.Bt you are correct,read the rules!

[Zac]

CCS SuperSport classes limit the engine mods, requiring stock airbox (which they will check in post race tech), stock compression, max 1mm overbore, no mods allowed to oem head, valves, cams, crank, rods, or cases, oem tranny, no mods to carb/throttle bodies.  These do not apply to singles, twins with less than 4 valves per cylinder, and pre '94 twins.

The SuperBike classes are pretty much open, no reduction of engine size from stock is allowed (so short-stroke 748s can't run lightweight), and water cooling can't be added to air cooled bikes and vise versa.  GP classes are unresricted.

FUSA rules are a little different

-z.

[MELK-MAN]

CCS SuperSport classes limit the engine mods, requiring stock airbox (which they will check in post race tech), stock compression, max 1mm overbore, no mods allowed to oem head, valves, cams, crank, rods, or cases, oem tranny, no mods to carb/throttle bodies.  These do not apply to singles, twins with less than 4 valves per cylinder, and pre '94 twins.

The SuperBike classes are pretty much open, no reduction of engine size from stock is allowed (so short-stroke 748s can't run lightweight), and water cooling can't be added to air cooled bikes and vise versa.  GP classes are unresricted.

FUSA rules are a little different

-z.

ccs supersport..
no "mods" to the heads but machining of the gasket surface is allowed. Stock compression pistons must be used..