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Old 12-20-2006, 11:43 PM
mainlylinux mainlylinux is offline
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Join Date: Nov 2003
Location: Michigan
Posts: 211
From what I've read the "bowl" area is usually the lowest hanging fruit (easiest to improve on) for most cylinder heads I've read about. also sometimes the chamber can be "unshrouded" to help flow (though on hemi combustion chambers I think this is a moot point). A kick butt valve job is usually well worth the money as well.

Part of the "magic" is that you can ruin the heads if you don't know what you are doing. If port size was the key then everything would be huge from the get go. But velocity and flow at a given valve lift is what is important, and typically a flow bench and velocity probe are used by head porters to measure their improvements.

In some cases epoxy or welding are used to radically change port shapes.

I'm betting that minor cleanup is all you'll want to do; hogging metal is a recipe for disaster unless you know where it needs to be coming from.

I ported a 2.2 dodge turbo head a long time ago (and spent hours and hours doing it). It made a huge difference - but I spent a bunch of time planning it out and researching it, and the 2.2 head design isn't as good out of the box as an xs11 head is, it's not a cross flow head (intake and exhaust ports are on the same side) and it uses a conventional wedge shape with 2 valves). The 1100 has a hemi shaped combustion chamber if I remember correctly.

Actually, it's a pretty cool looking combustion chamber. For kicks google the new hemi motor and read up on how efficient it's 2 valve design is - its pretty remarkable considering the hemi costs less to manufacture than the 360/318 did (http://www.allpar.com/mopar/new-mopar-hemi.html).

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Old 12-21-2006, 12:22 AM
goldcoastguy001 goldcoastguy001 is offline
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Join Date: Dec 2006
Location: Gold Coast, Australia
Posts: 137
I have to agree that port n polish is better suited to cars that are raced this also goes in hand to port matching with the manifolds etc that dosnt apply to bikes since the carbs mount in rubber boots and exhaust is almost mounted into the head anyway....the extra hp gained wouldnt really be beneficial compared to the cost if it was outworked by a shop, if done at home I believe the job although may look pretty to start with may not give much increase to hp.....Thats just my thought bout' the idea.....lol......Im rather new to the site so tale it with a grain of salt, but my thoughts of the topic are compared to the drag racing i use to do with big V8's.....let me know how you go anyway and if it actually made an extended differience....
1982 XS1100R
1982 XJ650
1983 VT400
1990 XVS Shadow
1983 Z1100

-I just love the look on their faces when you leave them standing in the dust after they've lined you up on your XS.
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Old 12-21-2006, 05:37 PM
MikeFromMT MikeFromMT is offline
Join Date: Jul 2005
Location: Traer IA
Posts: 71

let us know how it goes
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