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My old 1000SP project returns

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--- Quote from: Michael Moore on September 02, 2021, 03:29:38 PM ---Me too!  Maybe I can get it done before 30 years are up.   :grin:

--- End quote ---

Yes, you need to get going on this before I'm too old to ride it!  :thumb:

Michael Moore:
I wanted to start off with something fun on the SP, so I gathered up some port molds I had on hand and also made molds from a couple of Guzzi heads.

The molds I already had  were given to me by the late Ken Augustine (Kinetic Analysis) a very well known cylinder head guy (he did the heads for the Butler and Smith BMW Superbikes back in the day, and for many top riders and also factories).  Those I'll show are for a Yamaha TT500 with stock valves (47intake and 39 exhaust) and intake/exhaust manifold locations.  Ken told me that they had very impressive flow numbers.  I road raced a TT500 special in a Kenny Roberts frame for 6 years and Ken knew that I liked the motors. Ken's molds include the combustion chamber.

In the middle are heads by Craig Hanson that I had him do for the SP.  Craig did a lot of head/dyno development work over the years and built the heads on my Honda and Laverda vintage road racers.  These have Kibblewhite 44/37 valves.

The remaining set are from a stock head (I'd picked up an extra set) with 41/36 valves.

These are the raw scans of the port molds without any post-processing/smoothing of flaws where the molding might not have gone quite right, or had small tears develop when being removed from the heads.

The Guzzi ports are pretty crude.  It doesn't surprise me that stock head bikes often don't respond well to bolt on mods like big carbs etc.

Craig's ports have welded-up exhaust port floors and epoxy filler in the floor of the intake port.  You'll note he's added some offset for swirl in the intake.

Ken's TT500 ports are pretty cool, and show what can be done by someone who was a top-level porter for many decades.  The Yamaha is a 500 with 87x84mm bore/stroke, and somewhat less included valve angle than the Guzzi.  My SP with Gilardoni kit is 90x78.  The Yamaha intake would break out into the stud tunnels and is 10mm wider than Craig's intake.

Once I've dug out my flow bench and refreshed my memory on how to use it (and make a valve-opening fixture for the heads) I'll put the stock and modified Guzzi heads on it to get some comparison numbers.


Hi Michael,

Very cool story and thank you for posting the port info, that is right up my ally! :grin:

I too have a plan to do some work on the ports and it is very interesting to see how others have done it, specially the ones who have been at the top of the came for decades!

I am looking very much forward to following along!


Michael Moore:
I'm glad you found it interesting, I wasn't sure if it was too technical/esoteric to be of much interest to people.  I'll post more info as I accumulate it.

I am not sure how many would find it interesting (or how many people that actually drift over in this section of the forum) but I find that stuff very interesting. But if you're the type who believe that the Guzzi Engineers knew exactly what was best and that it shouldn't be messed with then maybe it is not such a interesting side of the forum here.

I will be looking much forward to updates on the build and don't feel you need to hold back with the details :) 


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