Porting and Polishing

[Anonymous]

Has anyone here tried porting and polishing your heads? I've done it on a few car engines, but never on a motorcycle. I'm sure it would work great, but wonder how people managed to get by the soft aluminum plugging the grinding materials...


Thanks,
Tim

 

[saaz]

Tim

I would be a bit careful about doing anything too drastic. The heads in stock form are a bit rough so a clean up will not hurt. I had my GS 1978 ported way back in 1984 or so by an expert with a flow bench who also did race bikes. It is a work of art, and it is easy to stuff it up.

John

 

[Anonymous]

I've done high level race mods to two-stroke bikes in the past, but as the porting is all in the cylinder it was mostly cast iron work. I also modified cast pistons for these engines with the same tools. I found then that using burrs is better than carbo stones for polishing. Keep the burr clean before it loads up and there is no problem.

For doing the heads of a four-stroke I would also try a rubber plug with a carborundum sleeve. I've used these on a dremel-like tool for plastic and found them good to work with. You probably won't want to take off much metal, just polish up the rough casting and maybe match the exhaust outlet to the header pipes.


Kim

 

[Anonymous]

Yeah, I'll need to remove quite a bit of material to match the header -and- the intakes. I have a spare head that i'll be doing the work on. These heads are not bad stock, but can be made much much better IMO. There is a lot of excess material under the valves. The only motorcycle head I have ever seen that looked great stock was from a Kawasaki ZX1100. There was very little that could have been cleaned, matched or otherwise on that thing. I've always wanted to do a motorcycle head, looks like i'll be firing up the air compressor and die grinder tomorrow.


Thanks,
Tim