Author Topic: How much should you shave a 11hp head for a 12.5 motor?  (Read 6534 times)

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Offline coreyk

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How much should you shave a 11hp head for a 12.5 motor?
« on: August 27, 2007, 03:54:04 pm »
How much do you recomend i take off? It's an 11hp head on a 12.5 briggs that has a port and polish. Thanks!
Guilford, Ct

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Offline Squidd

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #1 on: August 27, 2007, 04:52:01 pm »
The 25'' series  (11 hp) head already has a smaller combustion chamber which raises compression significantly (at least to the usable level)...

Why would you want to shave it down further..??

Randy Stys
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Offline George Herrin

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #2 on: August 27, 2007, 04:53:02 pm »
I don't shave any. I don't even use the 11 hp head anymore.
George Herrin #6
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Offline coreyk

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #3 on: August 27, 2007, 05:05:29 pm »
I was not sure if you should shave it anymore then it is. Also where can i buy an oversized piston and rings for the motor?
Guilford, Ct

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Offline Don Gienger

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #4 on: August 27, 2007, 06:40:56 pm »
Hey Watch this.

I don't shave my heads either. I make sure they are "True" and that is it. Same with the block.

Did you all catch that???? :confused:

George and me agree  :P

Don
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Offline birdman_express

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #5 on: August 27, 2007, 06:49:21 pm »
Hey Watch this.

I don't shave my heads either. I make sure they are "True" and that is it. Same with the block.

Did you all catch that???? :confused:

George and me agree  :P

Don

Where I am from, when someone says "Hey Watch this", they usually bleeed, but this one turned out good.  :thumbsup:
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Offline Squidd

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #6 on: August 27, 2007, 07:13:13 pm »
Where I am from, when someone says "Hey Watch this", they usually bleeed, but this one turned out good.  :thumbsup:

Where I come from they usually say "Hold my Beer...and watch this"..

And there is always bleeding involved..
Randy Stys
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Offline greenmachine

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #7 on: August 28, 2007, 01:00:16 am »
Hey Watch this.

I don't shave my heads either. I make sure they are "True" and that is it. Same with the block.

Did you all catch that???? :confused:

George and me agree  :P

Don
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BTW, Nobody holds my beer. That's considered alkyhol abuse down here :lol:
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Offline Dave Fires

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #8 on: August 28, 2007, 05:31:00 pm »
NONE !
Dave Fires
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Offline matt175

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #9 on: August 28, 2007, 10:15:54 pm »
I don't shave any. I don't even use the 11 hp head anymore.

i thought the 25cid head was better because of raising compression. would i be better off using the 28cid head? more volume?
Matt Hewett
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Offline Squidd

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #10 on: August 28, 2007, 10:21:42 pm »
Better flow...
Randy Stys
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Offline matt175

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #11 on: August 28, 2007, 10:26:26 pm »
would the 25 or 28 be better on a 28 with a cam? and would me having the 25 head on the 28 cause cutting out at higher rpm's? or would that be a fuel issue?
Matt Hewett
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Offline George Herrin

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #12 on: August 28, 2007, 10:49:05 pm »
The 25 head is not your cut out issue. The 12 hp head provides better flow. Also allows you more room/vloume to pack the almighty fuel and air into the cylinder. But you have to have the port work and carb and intake to get the flow also. Its a combination of all. By getting more in you raise the compression and have more HP overall. The 11hp head raises compression because it has less combustion area thus less vloume. For the smaller engine and not so good port work and not so modified carb sure it helps. But for an all out built to the hilt race motor the 12hp head is the way to go.
George Herrin #6
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Offline matt175

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #13 on: August 28, 2007, 10:58:25 pm »
thanks for the help george! i have done the port work, new hone and ring job, cam, exhaust spring and keeper setup on intake valve. now i need the carb work done. right now i am running the one piece carb. i did clean out all the sharp edges, but didn't re-jet it. do you think the carb could be causing the higher rpm cutting out? 
thanks
Matt
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Offline George Herrin

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Re: How much should you shave a 11hp head for a 12.5 motor?
« Reply #14 on: August 28, 2007, 11:02:47 pm »
Yes it could be. The walbro two piece is actually the better carb setup.
George Herrin #6
Indian Power.. You gotta Go big to beat em or Go HOME
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My other racer is a 1/5th scale Dirt Late Model!!!!

 

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