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Discussion Starter #1
Ready to finish my stage 4 build but wondering if there are better heads out there for the money than the screaming eagle heads?
 

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Sure there is! I am sure some of the forum sponsors would be able to take your stock heads and modify them. The SE heads aren't bad and they make a good heads to modify for peak performance.
I personally am not a big fan of head work IMO they don't give much bang for the buck for normal riding, but if you want to squeeze out all you can out of a engine than head work helps.
 

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As ironmark said you would be better off having your heads reworked,do your home work when it comes the shops that offer porting work,dont get hung up on numbers,when i had my heads done on my 01 95 inch RG i went with a local guy.He said that if i wanted bragging numbers on the flow bench thats what he could give me.But he said that my heads would work better if we worked with the specs of my cams.And that bike ran fantastic.So go with who makes sense to you and you are comfortable with.We have some Engine experts on this site who can help you out with any questions you may have.Good luck.
 
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It is the heads that make the power and it is the cam that dictates where in the rpm range the power will be. The porter decides if the flow is more for top end power or for low and mid range. Head work is not just for top end power. it has a direct effect on all the rpm's. anymore questions just ask IMO
 

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It is the heads that make the power and it is the cam that dictates where in the rpm range the power will be. The porter decides if the flow is more for top end power or for low and mid range. Head work is not just for top end power. it has a direct effect on all the rpm's. anymore questions just ask IMO
The cams have more to do with power than head work does. The cams determine the lift and duration of the valve lift and the timing of the engine.
The heads house the valves and spark plugs and rocker assembly and that's it. By putting in bigger intake and exhaust valves it just allows the pistons to draw in AFR or expel exhaust gases with less restriction which result in a minimum HP/torque gain. The port and polish just allows the gasses to flow smoothly when entering/exiting the engine.
In general a engine such as a 103 can only draw in so much AFR on the intake stroke and that will not change unless you pressurize the intake with a turbo, the size of the valves will not change the volume of AFR in the cylinder. Larger valves just allows the energy (3 to 5 ft lbs of torque on a 103) it takes to draw in AFR or expel exhaust gas to be transferred to the rear wheel.
Pull up the dyno sheets on a 103 engine (Fuel Moto has a good dyno section) and compare dynos on 103 builds. The biggest power gain is from the cam and the smallest power gain is from headwork.
Of course the bigger the engine the bigger the power gain but the percentage of gain is pretty much the same.
It is your bike and if you want to get maximum performance then head work will work well for you. If you just cruise do general riding /touring head work isn't really necessary.
This is JMO I been on both sides of this fence and for my riding style the big build was a big waste of money for me.
 

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All one has to do is google " cylinder head porting" to see the value obtained by this process. Read what Dennish, Vizard, Mondello and others say about it. A cam all by itself, just as worked heads all by themselves don't tell the whole story. A build with proven components, (heads, cams, compression, exhaust, etc.) working in concert is what makes power across a broad range, low, mid and high.
 

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The cams have more to do with power than head work does. The cams determine the lift and duration of the valve lift and the timing of the engine.

The heads house the valves and spark plugs and rocker assembly and that's it. By putting in bigger intake and exhaust valves it just allows the pistons to draw in AFR or expel exhaust gases with less restriction which result in a minimum HP/torque gain. The port and polish just allows the gasses to flow smoothly when entering/exiting the engine.

In general a engine such as a 103 can only draw in so much AFR on the intake stroke and that will not change unless you pressurize the intake with a turbo, the size of the valves will not change the volume of AFR in the cylinder. Larger valves just allows the energy (3 to 5 ft lbs of torque on a 103) it takes to draw in AFR or expel exhaust gas to be transferred to the rear wheel.

Pull up the dyno sheets on a 103 engine (Fuel Moto has a good dyno section) and compare dynos on 103 builds. The biggest power gain is from the cam and the smallest power gain is from headwork.

Of course the bigger the engine the bigger the power gain but the percentage of gain is pretty much the same.

It is your bike and if you want to get maximum performance then head work will work well for you. If you just cruise do general riding /touring head work isn't really necessary.

This is JMO I been on both sides of this fence and for my riding style the big build was a big waste of money for me.

Im not positive you truly understand the role that the heads play in your total engine package.

Your over emphasis on cams is flawed. Cams, although important are only one component of the total system. Such things as port velocity and quench are often overlooked. To prove my point; Go to the hardware store and go to the PVC pipe section and pick up a 3" diameter pipe and then a 1.5" diameter pipe, both a few feet long. Hold your hand over the end and blow out. Which pipe were you able to feel your breath through? Which one is more forceful in pushing your hand away? Of coarse it'll be the smaller pipe! This is a gross oversimplification of the importance of proper porting but you get the idea none the less.




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Port shape, size, valve shape, size, seat angles, etc, all come togather to establish a good/great cylinder head, and yes, good cylinder head work enhances from bottom to top.
Our in-house(not all shops can claim that, btw)cylinder head program has 5 different levels of T/C work.
Happy to get you going down the right path. :)
Scott
 

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Remember that an engine is just a big air pump. The more air you move, the more power from the pump. Head work is done to help with the atomization of the fuel mixture and to increase the efficiency of the combustion phase of the pump. Better atomization of the fuel mixture will result in more of the fuel being ignited and a greater potential of increased air flow through the pump.
 

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Damn,,, I thought you found us a new brothel to visit with Head being in the title... :grin:


I see the big boys have weighed in with insight coming from their experience. I love reading these threads. Very informative.
 

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We look for the ability of the head to start pulling good as soon as we crack the valve off the seat at .100" lift, and continue to pull past the cams peak lift while on the flow bench.
Also mid-lift flow is VERY important as the valve is in that area more than anywhere else, on both opening and closing events.
Scott
 

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Discussion Starter #13
So being that I am running Harley cams would it be better to run the Harley heads? I would assume nobody has better heads than Harley to go with there cams? Figure Harley heads run about 1k bucks whats the going rate to have my stock heads worked over by somebody else
 

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So being that I am running Harley cams would it be better to run the Harley heads? I would assume nobody has better heads than Harley to go with there cams? Figure Harley heads run about 1k bucks whats the going rate to have my stock heads worked over by somebody else
Many heads that are much better than those. :)
Scott
 
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