BSR Yamaha R1 Cylinder Head Porting 

Ya, these do have about as many valves as they could cram in there. It adds a lot of time and hassle to the port work. That Honda (NR 500) kind of failed, at least partially because of the need for two rods per piston, it was impossible to get both rods to have the exact same bearing clearances/tolerances to keep the piston square in the bore. Causing rapid wear and loss of ring sealing/compression. You are right, it would be interesting to see a direct comparison on smooth vs rough inlet ports. I've not tried it myself. I've done both but not on the same motor/application. I just go along with the (now) generally accepted practice of leaving them slightly rough. I believe cars guys have done this experiment but I can't say exactly who or on which application.

***** some guys are having the intake prts dimpled on cnc machines now. Like a golfball surface

Ya, I've thought of trying that but it'd be too hard to get right by hand, I think. I get really good gains with the methods I use. Generally 10-15 HP peak gains (on 1000cc motor) with good gains all throughout the rev range. It's not an all or nothing modification. I did a Suzuki DR650 and made a 49% increase in power (with cams) turned out to be the most powerful DR in the world. Too bad I didn't think to make a video out of it.

***** Awe man I love that big bush pig DR. Did you use the 790 top end? The DR head looks abnormal compared to other 650s with those tiny valves. Thats impressive. Probably over 50 ft lbs at the wheel?

I used a 700 top end (biggest available at the time, 2009). I forget the torque# (I've switched computers since then) but it went from 32 Hp to 52. I increased the compression also with a thinner gasket and milled head. Pumper carb, FMF pipe, pretty much anything I could think of. Set up with 17" street wheels. It was a blast to ride (Wheelie machine) but it still topped out at about 100MPH.

That's funny because if I take the head off after I've already milled it there are no new marks.... You really think the head is that soft or they've torqued it down so hard as to leave permanent indentations?

Yes

Aluminum vs steel

I need you on my team, are you looking for work?

I have been working at a well known VW aftermarket shop on the west coast for the last 24 years.I enjoy porting VW and motorcycle heads on my free time.Where are you located?

Message sent.

Gains of 10-05 peak HP with good gains all throughout the rev range. Email wfofz1@hotmail.com for pricing and options.

What do you mean by 10-05 hp?? 10-15 perhaps?? If so wow my head will come to you the first time it’s off. That’s awesome. Mine has only 4,000 miles on it and I’m not sure I’m ready to go pulling it apart but for 10/15 more hp plus gains throughout the rev range that’s impressive for sure. Would the head come back ready to install or would the lash adjustments still need done??

That head belongs to Brian. I can do another one for you if you'd like. wfofz1@hotmail.com

It can. You just have to remove the cylinder head. I have found that it is much easier to remove the whole motor because then you can work on it while it sits on s bench rather than on the ground.

Have a newer camera now= better audio