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Own head work - Port and polish

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Good pictures but fairly extreme for 'home porting'.  All depends on use, ie. the above good for competition but epoxy work and shortened guides IMO really not good idea for a road bike long term. I've  cleaned up a few heads - car and bike, and can't give conclusive improvement results as this work was usually done with other improvements not independently! Only advice i'd offer is don't go mad removing metal, just clean off flash and mold lines, blend manifolds / gaskets / ports to each other, semi rough grind finish to inlet port - exhaust can be more polished, watch out for the valve seats as easy to 'kiss' with the stone then they'll need cutting !

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Focus on the combustion chambers.  The valves on the 1100 are quite small, so there are good gains in unshrouding the valves. this obviously lowers the cr a bit, so skimming the head to get the cr back is worth while with stock pistons. Stick some old valves in the head to avoid damaging the seats

Port wise, clean up the short side radius, and blend in the throat around the seats, and match the ports to the carb rubbers, make the ports, 0.5mm bigger than the boot for best flow 

The Pictures above are pretty good.

Similar here, but slightly better imho.


This head below made 156bhp on stock valves and a 1216cc kit.


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2 hours ago, dupersunc said:

Kent SUZ1 inlet. stock exhaust.  can t remember the timing figures.

Fcr41 carbs, micron 4-2-1 exhaust.  ignitech ignition with quite a lot of advance.

Wow - seems my 1186 motor making 144hp wasn't too bad! M head with only port clean up, 36mm CV's, Dynojetted, std cams, Dyna 2000 and a 4-2-1 one off pipe set and V&H Supersport can.

Kawazuki Dyno Run002.JPG

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All this info is very good guys, but I cant help think that we are missing the main point here in this thread, sod all the porting and tuning and dyno figures.  But god damn that Betty Rubble has a fantastic figure.. what an arse.....

Thanks go to Gixer1460 for inadvertently pointing that out to me....


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