Head Milling and what it does to you...

wow erbe01 yours looks nice but you should mine, its crazy cut down, hogged out so much you can't even see where the bowl and gasket surfaces even begin :), ill take a pic of it the next time ive got it apart... and corey just remember you get what you pay for...
 
It's important to mention that like anything else there is a limit on milling the head. Do too much and you will get pinging (detonation), autoignition, overheating and a flat topend- even with race gas. Other stuff to keep in mind is the more compression you have the harder it is on bearings.
On my own motor I've found the linit is the heads ability to stay sealed.
 
I'm having some piston mods done also with teh Blaster Porting and the dome is to match the piston mods, also look close there are cut angles in it, believe it or not this cut helps the torque that I'm looking for in this play dunner motor.
Wish I had the 2 heads of the 250R I have an 86 and a 88 the domes are factory but completely different, the 86 is large like the new cut one and the 88 is small like the stock Blaster one.Every likes to run the 86 head.
 
See in all my quads I run some race fuel, pump gas is just garbage :
LT500 VP-110 Straight 225 compression 927 25 to 1
DS-730 VP-110 Straight 14 to 1 compression
TRX250R VP-110 50/50 mix about 100 oct 190 Compression 927 32 to 1
Blaster VP-110 50/50 mix about 100 oct 180 Compression 927 32 to 1
Mojave VP-110 20/80 mix about 95 oct 11 to 1 Compression
LT80 PUMP GAS for know Still tryin g to burn up the 2 gals of super M maxima
 
yeah ive got to run 110 myself, but all the work done to my motor was done by Winky @ Diamond National, i feel pretty confident that they know what they are doing :)
 
so is it really more cost effective or just cheaper by the gallon? i pay $5/gal for 110...
 
Cheaper by the gallon but not really cost effective after you factor in the burn rate.
It does offer a nice increase in power over gas. These air-cooled motors IMO benefit more from it then the water cooled ones because of the increase cooling over gas. Meth will let you run higher compression for more power while letting you ride longer without overheating.
It's how I get away with a modded out air-cooled big-bore on the trails...PB
 
how much does it cost to have the head shaved? is the squish angle really that big of a deal? Even if i only want to take .02 off.. if it is i guess i would have to send my head to a race shop that specializes in that? becuase if the squish angle isn't that big of a deal.. i mean i'm not building a fully worked motor just wanna add some some cheaper affordable upgrades to my motor rebuild. becuase i could take the head to a friend at a machine shop and get it done for practically free..
 
Ok guys I have the veto's high compression piston and gasket kit, I run 93 with no prablems, can I shave my head any without using race gas? I'm not sure how the thin gaskets compare to shaved head? Thanks for the help
 
hmm.. .not really sure what the squish clearance is stock, but i know it's too big and the band is at the wrong angle. the band is supposed to match the piston top and the smaller the clearance the better, just so the piston doesn't hit the head.

all the gas/air in the squish band does not get burned. so when you make that area smaller, it all gets compressed into the combustion chamber and gets burned, making more power.
 
The stock blaster set up is:
The piston is in the hole .030 inches
The compressed gasket thickness is .030 to .035
The step in the head various to .030 to .040 inches
The piston to head could be could be as much as .100 inches
The piston squish angle is 9 and the head is 18 plus
It needs to re-machined
stock head/my trail head design
http://flickr.com/photos/kennedypower/
 
you guys better stop worrying about how much comp. your air-cooled motor has, squish velocity means everything from seizing it to breaking pistons, forget about race gas for your blaster and make sure you have the right squish angle, correct width, right clearance, and the right C.R. for what you need don't run over 145 lbs. on a trail or mx blaster, you need to finish to win.
 
I read all these posts and erbe is the only one getting it, squish angle for a blaster is 9 degree's, the width of that 9 degree band makes a difference, the distance between the piston and squish band makes a difference, like Kennedy says the squish clearance is at .100 stock and thats alot, so to say milling the surface down .035 would get your clearance down to .065 still alot, .040 is about the minimum you want squish clearance, now I would think if your running a flat track motor (hi RPM's) the squish band needs to be narrower maybe 10mm wide, but being your running a constant hi RPM you gotta keep the compression down around 140 no higher or you'll stick it, (that requires 94 octane! NO RACE GAS) now if your running 300 foot drags lets still keep the .040 clearance lets go a little wider on the band (more torque) maybe 12mm wide, and lets get the compression up around 165 (no more than 110 octane) that will start building alot of heat that an air cooler cannot get rid of, hence 300 foot. and now for the guys trail riding 135 lbs. compression no-lead premium at best maybe even mid-grade do not over octane your motor it is not healthy! someone asked about Vito's head gasket I believe they are .015 thinner than stock, well you just brought the head .015 closer same as milling off .015
 
holly crap, after reading this complete 10page thread my brian is f*cking mushed. i really need some schooling in this sh*t.....i think ill stay with someone doing this for me and then learn as it breaks
 
gonzo said:
don't run over 145 lbs. on a trail or mx blaster, you need to finish to win.
Click to expand...

I agree, but disagree. You do have to finish in order to win. But having compression that is nearly stock won't help your cause. You can be the best rider with the best suspension out there, but you won't likely win. You need all the pieces of the puzzle in order to win and a hot motor is one of them. The more the compression the higher horsepower and torque numbers you will have all accross the board. I never had a motor failure due to high compression when I raced blasters and I was running in the neighborhood of 185-190lbs. It was a Mx bike and I raced it for nearly 3 years if anyone is wondering.
 
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milled head from ebay came today, im not happy with the looks of it, does this thing look like it was even close to done right?

3462462601_ca957a30ca_b.jpg


is this even safe?
 
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