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Discussion Starter · #1 · (Edited)
For all those guys who ordered their heads shaved way too much to bump up the comp ratio but are now getting ping...................you can use a die grinder and reshape the area around the intake and exhaust on each head to increase the chamber volume (cc`s) and lessen the CR..............naturally you cc the heads to ensure you have removed equal amounts and to calculate your new cr............you can even shape one head until optimum and then make a template by cutting up a scereal box and using a ball pean hammer to tap out the shape (cutting the cardboard to exact shape then tracing the other head to achieve the same shape.

This actually will improve cylinder fill in some applications (dependant on the head chamber design) particularly on some aftermarket sportster heads) by un shrouding the valve..............

This is better than going to a thicker head gasket as you do not disturb the squish band thickness, which is so important for achieving the correct burn rate.............faster is better!

Dont forget to index your plugs...........

Merry xmas...................Ozzie
 

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to much compression why do the work just put in more cam:clap:
 

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Discussion Starter · #4 ·
Otto said:
to much compression why do the work just put in more cam:clap:


OR like otto says, you can put in more cam.............................:whistle:


Mery xmas otto......................Ozzie
 

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Why not use that cereal box and cut it to match the head gasket..1 or 2 thicknesses should bring the CR down a tad...
 

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Ozzie In Arabia said:
For all those guys who ordered their heads shaved way too much to bump up the comp ratio but are now getting ping...................you can use a die grinder and reshape the area around the intake and exhaust on each head to increase the chamber volume (cc`s) and lessen the CR..............naturally you cc the heads to ensure you have removed equal amounts and to calculate your new cr............you can even shape one head until optimum and then make a template by cutting up a scereal box and using a ball pean hammer to tap out the shape (cutting the cardboard to exact shape then tracing the other head to achieve the same shape.

This actually will improve cylinder fill in some applications (dependant on the head chamber design) particularly on some aftermarket sportster heads) by un shrouding the valve..............

This is better than going to a thicker head gasket as you do not disturb the squish band thickness, which is so important for achieving the correct burn rate.............faster is better!

Dont forget to index your plugs...........

Merry xmas...................Ozzie
That sounds like a real PITA! I think I'd just take my heads off and send them back out to a Dewey or Bean for a little touch up...I wouldn't think it would cost as much as a full port job after all.
 

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Discussion Starter · #7 · (Edited)
Seahag said:
That sounds like a real PITA! I think I'd just take my heads off and send them back out to a Dewey or Bean for a little touch up...I wouldn't think it would cost as much as a full port job after all.[/QUOTE

Maybe for you Seahag..............but many here like having a go themselves and getting their hands dirty, and it would get real expensive to ship from outside the US.................the idea was that this possible stuff up can be remedied and my way would only be the cost of the dremel that I assume at least some here would have.

Ozzie
 

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merry xmas to you to ozzie. :wavey:

i was just meaning that there was a balnce point for almost all compression/cam combo
 

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Discussion Starter · #9 · (Edited)
Otto said:
merry xmas to you to ozzie. :wavey:

i was just meaning that there was a balnce point for almost all compression/cam combo
Hey there Otto, merry xmas to you my friend...............your point was fully understood as it and thicker head gaskets are the most common way to resolve the issue.

I was just advising on a possible way to stop the ping without effecting squish and staying with the cam of choice as a minimal outlay to the newbies......and really only meant for 2 valve heads as 4 with valve heads there is not much squish area left to play with.....and this works on any 2 valve head.

Just some old school stuff we did as kids.....................when we took our heads to the local machine shop and said "take off 80 thou mate!" then the bike pinged like crazy and we realised we over did it................got to say at this point in my knowledge cycle that none of us ever heard about squish............just that we new that a thinner gasket gave more power, and we put it down to smaller combustion chambers and more compression until we learned......



You have a great and safe xmas........................Ozzie
 

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Ozzie In Arabia said:
Seahag said:
That sounds like a real PITA! I think I'd just take my heads off and send them back out to a Dewey or Bean for a little touch up...I wouldn't think it would cost as much as a full port job after all.[/QUOTE

Maybe for you Seahag..............but many here like having a go themselves and getting their hands dirty, and it would get real expensive to ship from outside the US.................the idea was that this possible stuff up can be remedied and my way would only be the cost of the dremel that I assume at least some here would have.

Ozzie
I'd definately have to give it a try if I lived where you do Ozzie...If I had more than one bike too, I might be a lot more likely to dig deeper than assembly/dissasembly; but if I screw up the one I've got, there will be no riding for me for a while...No fun.

I certainly didn't mean to dismiss your information. You take care Ozzie.

Clay
 

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Discussion Starter · #11 ·
Seahag said:
Ozzie In Arabia said:
I'd definately have to give it a try if I lived where you do Ozzie...If I had more than one bike too, I might be a lot more likely to dig deeper than assembly/dissasembly; but if I screw up the one I've got, there will be no riding for me for a while...No fun.

I certainly didn't mean to dismiss your information. You take care Ozzie.

Clay
No sweat Seahag..................and Merry Xmas to you too, I probably should have thrown in a smiley........sorry for that.


All the best, Ozzie
 

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this is true ozzie now here is another angle for you a little less time consuming depending how far out af whack it really is you could 1 retart cam timing and 2 replace rockers with different ratio thus changing the compression requirements for a given cam
 
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