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Discussion Starter · #1 ·
I have a 13 fltrx and so far only things done are a d&d fatcat, hi flow air cleaner,and tuned with power commander v from fuel moto. I picked up a set of woods 777 cams and on the fence how to proceed. What can i do to get the compression up where is best for these cams, 10.4 to 1 i believe. Have been sitting on a set of se 110 heads for a couple years and debated getting the se pistons that match these heads. Anyone given these a try on a 103? Or am i better off going another route? I dont want to go into the lower end at this point,maybe in winter if time and funds allow. Any input would be appreciated.
 

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We've used those 110" heads on 107"ers many times now.
I would not suggest fully porting those on a 103"er as it could steal the low end torque from the build.
That said, as long as the compression could be brought to that 10.4 level under those 95-96cc chambers you should have a good runner.
We are currently installing a set of thos 110" Heads on a 117", for a client from Syracuse, NY.
Wood 8/55 HPI/Borezilla.:)
Scott
 

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Discussion Starter · #3 ·
So I should be able to use the se 10.5 to 1 domes made for those chambers ? down the road I plan of probably going bigger and if those heads are usable would like to use them. They do need some updates as they had issues with guides and seals if I remember right. Would like to stick with as much harley parts as possible since I get a substantial discount on them.
 

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Discussion Starter · #5 ·
Is it even worth giving consideration to the 110 heads? I've spent alot of time reading different things and many conflicting opinions for smaller motor. Roughly what would it cost to have these have the issues fixed? And they also need front motor brace holes drilled and tapped.

If I don't use the 110 heads are changing to different pistons to get me 10.5 to 1 gonna be a noticeable difference over running cams at stock compression? I have cams lifters and pushrods already. Wood 777 cams, and s&s lifters and pushrods.
 

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You are looking at putting a whole bunch of money into a 103" and you also mention going bigger later. Two totally different directions with parts. My advice is to do a solid cam only upgrade now and kill it with cubic inches when the time is right. You are going to need to address the crank if you put too much more than a cam into it and by then you may as well cut the cases, upgrade the bearings, and go 117" or 124". Save the funds now and build it right ONCE.
 

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Same here, check the depth of the piston in the hole, then decide on a .030 head gasket or what would be appropriate to achieve the squish you need to up the compression. Keep the flat top pistons with the woods 777 or sell that and put an Andrews 57H or another appropriate cam of choice and ride the crap out of it.
 

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Doing the crank is on my list of to do things . I didn't think changing to the .030 head gasket raised compression much? Is there another effect it also has?
Yes it does raise compression, figured correctly, you shave the heads and use a thinner head gasket to achieve desired compression. Just remember, plan your compression on the cam you choose. That is a must. I've done the domed pistons on several bikes using the Dave Mackie heads and pistons. I love them but now, I stick to flat top and achieve a very strong engine. Must of us don't need or want race engines and deal with poor gas quality and pre detonation issues.
 

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Simply changing from stock to a .030 head gasket will raise your compression to roughly 10.15-1. Using a .030 head gasket also sets your squish zone to a more optimal measurement.

Taken from another site:
"So what is squish clearance? Also known as "quench", squish refers to the area or areas where the piston comes very close to the cylinder head while passing through top dead center (TDC). Even though the fire has already been lit, these areas still contain unburned air/fuel mix as the piston arrives. The piston sandwiches the air/fuel up next to the head, causing it to "squish", and shoot out toward the flame front. Think in terms of stepping on a tube of toothpaste. The result is more chamber turbulence, better atomization of the fuel, and the squish band even has a cooling effect on the fuel."
 

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Discussion Starter · #12 ·
I thought the compression came out to be lower than that going to .030 head gasket. Think the calculator on bigboyz site showed it going from 9.6 to about 9.85 or so. If I can get over 10 to 1 by just doing the gasket it's something I would surely do and just run the cams for now.
 

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Discussion Starter · #14 ·
If that's the case it should put me closer to where cams will be happy. Is valve to piston clearance gonna be fine or something I need to clay and check? This will be 1st harley I'll be wrenching on so in those regards it's new to me. Done alot of work to cars and drag snowmobiles so am comfortable wrenching and am a machinist for work.
 

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I'd check just to be sure. You are going to have your heads off anyway. If you are using the stock valves you should be just fine but if using larger valves the stock valve pockets are small. TDC is .200/.187.

While you are at it reroute your breathers and it will really help with all the carbon build up in the cylinders. You'll see what I mean when you get in there.


Sent from Motorcycle.com Free App
 

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Yes. The head breathers are routed into the intake. Certain backing plates allow you to reroute the heads to vent elsewhere. PM me your email address and I'll shoot a couple of photos of how I did it.
 
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