A thing of beauty...

[Anders]

The pics speak for themselves.. Ported intake, exhaust and welded combustion chamber to give 11,5:1 compression with a stock piston.

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[DAVID THOMPSON]

i am a basic daily driver type fellow ... but i do love it when an artist is at work
dave

[Anders]

Well I can't take credit for the headwork myself, I'm just the custodian of the head at the time being.

I came across this head as part of a box of spares which came with the Mikuni TM34-B65 carbs that I bought some time ago.

The head is ported and welded combustion chamber by a legendary tuner "Grottis" who passed away a few years ago, amongst other things he ported the heads used in Belgarda (producers of the SZR) Racing R7 bikes (also 5-valve), which produced more power than Norioki Hagas Factory Yamaha R7 Superbike.

This SZR head has been modified along the same lines as the R7 head, you can see the similarities in the attached picture.
Unfortunatley the SZR head has suffered a light cam seizure, the "races" are a bit scuffed but nothing too bad but I'm looking for ideas to save/refurbish the head.

Grottis ported Yamaha R7 head

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If you compare with a stock SZR head you will appreciate the amount of work that has gone into this.

Stock Yamaha head

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