The Best High Performance Head Work....

[KenHawk]

I've kinda gotten myself painted into a corner here...

When I had my R100 engine refreshed, I had a Nikasil 1000cc top end with Hi-comp pistons sitting here, so I had that stuff installed, along with some fresh 77 Big Valve heads. Well, the bike runs like a raped ape but I'm also aware that I'm leaving some free HP on the table, because of the mismatch between the squish band heads and the later model, domed pistons.

Well, a couple of days ago I was cleaning up the shop and discovered that I have a perfectly decent, rebuildable pair of 80-83 heads! Imagine that... I have(Or had!) so much crap that I actually lost a pair of good heads that should be a much better match for my later-model, hi-comp pistons.

I gave Chris at San Jose BMW a call and IRRC he quoted me right around $500 for the head porting and a rebuild, and a little more to add in 44mm intake valves. At the same time he wants to install a 336 cam. Something else thats in my parts stash. Hmmm... My other choice might be to have a set of custom, 1977 style squish band pistons made to match my new cylinders but that seems like a lot of extra work and added expense for a mere street bike. Either way it looks like I'm going to be throwing another grand or so at the old bike... I wonder what Donnas gonna say?

Anyway... Do any of you have info concerning other guys/shops doing performance head porting here in the states? I'm leaning towards San Jose for the work, because they're close to home but I just gotta ask.

[r90s]

I was going through the same process as you some years ago. I sent a pair of old stock, brand new, R90S heads to Chris for a mild port job. Instructions were clearly lid out as to exactly what I wanted done.
They were returned with a full blown phase IV race conversion- hogged out ports and oversized valves- and the bill was twice what it should have been.
Besides that, the combustion chambers were damaged with crescent-shaped cuts around the valve seat area, fairly deep and long - not scratches, but deep gouges.

Chris' response? "Those holes will fill up with carbon anyway" and "Put them on, you'll like them".

Well, I wasn't building a race motor with different cams, carbs, and exhaust, so the race heads would have been a disaster. And the damage would have made for serious knock when the sharp edges heated up.

I managed to get a refund from the credit card bank for Chris' charges, but the would not replace - or exchange - the heads.

Since then, others have shared similar stories. I'd choose anyone other than San Jose for this work.

Personally, I use Engine Dynamics in Petaluma:

http://www.enginedynamics.com/

If you speak with Chris again, mention my name.

Cheers,
Jon-Lars Sorenson
Beverly, WA