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Discussion Starter #1
Was considering on having my head milled. I was just wondering if and how much to take off. I am running stock pistons with the .45 head gasket. I always run 93 but don't want to have to run race fuel. I have the PC3 and ignition module also if that helps. Thanks guys
 

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You wont have to run race gas with head milled an .45 gasket..Talk to BGMAGMA, he's got thin HG milled head and 13.5:1 JE's..runs 91 just fine

I have same setup as him minus the thin HG, with 3 degrees advanced and runs great on pump 91...


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Discussion Starter #3
You wont have to run race gas with head milled an .45 gasket..Talk to BGMAGMA, he's got thin HG milled head and 13.5:1 JE's..runs 91 just fine

I have same setup as him minus the thin HG, with 3 degrees advanced and runs great on pump 91...


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my timing starts in the negative in the lower rpms and jumps up as the rpms go up. it goes all the way to +8 till it hits 13000
 

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Slow Poke
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You wont have to run race gas with head milled an .45 gasket..Talk to BGMAGMA, he's got thin HG milled head and 13.5:1 JE's..runs 91 just fine

I have same setup as him minus the thin HG, with 3 degrees advanced and runs great on pump 91...


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:+1: have about .08 milled and a .45 hg and run pump gas fine. No timing advance though. Not yet anyway :mrgreen:


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Discussion Starter #6
:+1: have about .08 milled and a .45 hg and run pump gas fine. No timing advance though. Not yet anyway :mrgreen:


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I wonder if I would be safe at 10 or should I just stay at 5.
 

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.004" is about the thickness of a piece of paper.....so from 5 to 10 isn't a drastic jump, but an increase non the less.....with the stock pistons and head giving a 12.7:1 comp, there is lots of room before you get into race gas territory.......being if you did 10 with the thin gasket, and for some crazy reason it was too much, you can alway give that back from a thicker gasket......milling isn't cheap and it sure is alot of work compared to swapping head gaskets. :)
 

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Supercharged Mod
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I am using Wossner 13.5:1 pistons and a 0.55mm head gasket, no head milling, Web camshafts (the milder of the two available choices) and I undid the 3-degree timing advance that I had before building the engine. With those pistons, 0.45mm head gasket would have put piston-to-head clearance scary tight. Maybe the stock pistons have a slightly different deck height but you'd better check. Unfortunately, the 0.55mm head gasket appears to be no longer available.

I've done all of my tuning on PetroCanada 94, which is what I plan to use whenever possible, and there's no detonation as far as I can tell. Had one fill-up of Shell V-power 91, it didn't feel right and I was nervous about it ... I'd rather not find out the hard way that it wants more. At this point I'm planning to run it on 94, and I can use 91 if I can't get 94 and need to get somewhere, but not riding hard ... I just finished resetting the valve clearances after putting about 1000 km on the engine (and deciding that I'd rather use Kawasaki's valve clearance specs than Web Camshafts much looser, excessively noisy specs), we'll see if that changes anything tomorrow.
 

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Discussion Starter #9
I am using Wossner 13.5:1 pistons and a 0.55mm head gasket, no head milling, Web camshafts (the milder of the two available choices) and I undid the 3-degree timing advance that I had before building the engine. With those pistons, 0.45mm head gasket would have put piston-to-head clearance scary tight. Maybe the stock pistons have a slightly different deck height but you'd better check. Unfortunately, the 0.55mm head gasket appears to be no longer available.

I've done all of my tuning on PetroCanada 94, which is what I plan to use whenever possible, and there's no detonation as far as I can tell. Had one fill-up of Shell V-power 91, it didn't feel right and I was nervous about it ... I'd rather not find out the hard way that it wants more. At this point I'm planning to run it on 94, and I can use 91 if I can't get 94 and need to get somewhere, but not riding hard ... I just finished resetting the valve clearances after putting about 1000 km on the engine (and deciding that I'd rather use Kawasaki's valve clearance specs than Web Camshafts much looser, excessively noisy specs), we'll see if that changes anything tomorrow.
whats funny is technically if you add a racing cam or a cam that has a higher lift and duration on the intake side, you are adding compression. so stock head with the .45 head gasket and racing intake cam, means you have more compression than if you just had the .45 gasket alone.
 

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Supercharged Mod
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Camshaft effects are not that straightforward. Your statement is correct at high revs (where the engine is "on the cam"), but not at low revs. A camshaft with a later intake valve closure will let out more of the charge that just went in, thus lowering the dynamic compression ratio at low revs (where detonation tends to be more prevalent).
 

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Discussion Starter #11
Camshaft effects are not that straightforward. Your statement is correct at high revs (where the engine is "on the cam"), but not at low revs. A camshaft with a later intake valve closure will let out more of the charge that just went in, thus lowering the dynamic compression ratio at low revs (where detonation tends to be more prevalent).
interesting.
 
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