Topic: Thanks Mike Rieck..........................BIG PORT HEAD

[Jim F]

Here ya go guys
another master piece from Mr. Rieck.
This is Mikes stage 3 porting
Porting alone is worth 12 to 15 Hp
but going from 29mm CRs to 33mm flat slides. Who knows what the final HP is going to be

big port head  with 33mm intakes
bronze guides
Ti retainers with heavy  springs
33mm flat slides

Cant wait to get the engine run in to dyno this baby

Thanks again Mike
Jim F.

[Jerry Rxman Griffin aka MuthaF'er]

Mike the maestro stikes again. UPS is dropping mine off to Mike tomorrow. I'm looking forward to your dyno numbers with the 33's. I'm doing the 34mm valves with the 5mm stems and had planned on using 31CR's. What size pistons are you using? I know 33CR's can be adapted with available stock intake runners from Honda according to Sudco.

Jerry   

[kpier883]

I noted in another thread that this is for a GS850.  Were the ports originally round and Mike changed them to the current shape with the semi D shape at the bottom? 

Could you comment on the shape leading up to the valve guide?

What about the area behind the valve guide (past the guide going in from the intake side) - did you cut upward there?

[Jim F]

You would have to ask mike the details for the shape of the ports and
the reasoning behind this, But based on the engine size
which is an 840 kit with 10.5 compression
the cams have a 390 lift
and the carburetors he came up with the best shape for the ports to maximize flow

He said that based on the shape of the ports
that the head alone is worth another 12 to 15 Hp alone

The dyno will follow as soon as the motor has a good run in