Bikers Festival Francorchamps

Otto

Otto

Full member
Location
Holland
Last weekend we had a great weekend at Spa Francorchamps with the Laverda’s.
Great wether. In the box were 10 orange bikes and at the paddock same number I guess.
The Zane 650 was fantastic.
 

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Did Larry's bike come complete, Marnix? I bought his SFC rear hub, disc, sprockets. He'd converted to Suzuki cast wheels. Or did he have another SFC? I thought Wolfgang had Larry's old SFC.
 
Yes it did come complete in urgent need of a complete overhaul. When Larry Strung raced the SFC in the 80ies he didn’t trust the magnesium hub and fitted a Suzuki GS750 rear hub. Tim Parker did same with his Elettronica SFC at the time. I removed the hub and fitted an original magnesium hub and disc. Never had issues with them. Still have the Suzuki hub (photo).

Wolfgang did buy the SFC off Larry, yes. Then it went to Germany, then Scotland and finally Holland.

Marnix
 

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MarnixSFC said:
Yes it did come complete in urgent need of a complete overhaul. When Larry Strung raced the SFC in the 80ies he didn’t trust the magnesium hub and fitted a Suzuki GS750 rear hub. Tim Parker did same with his Elettronica SFC at the time. I removed the hub and fitted an original magnesium hub and disc. Never had issues with them. Still have the Suzuki hub (photo).

Wolfgang did buy the SFC off Larry, yes. Then it went to Germany, then Scotland and finally Holland.

Marnix
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Cool story. A bit of history there. Larry also offered me the SFC swingarm but I opted out of that; I think he had the Suzuki swingarm, front and and wheels on the bike (or that may have been his and/or his wife's SF). The hub and bits I had for years and eventually swapped them all for the SF3 gearbox and clutch complete that's in the SFQ.

What additional performance work in the motor now, Marnix?
 
.. and the ASI MOTO Show at Varano with MML gang in May with my 1973 Bol d’Or machines: Segoni and SFC. All three memorable events in their own way. Happy days.

Marnix
piranha-bro2 said:
Cool story. A bit of history there. Larry also offered me the SFC swingarm but I opted out of that; I think he had the Suzuki swingarm, front and and wheels on the bike (or that may have been his and/or his wife's SF). The hub and bits I had for years and eventually swapped them all for the SF3 gearbox and clutch complete that's in the SFQ.

What additional performance work in the motor now, Marnix?
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Larry had a box section swingarm made in UK (JMC) for the SFC, so the original swingarm was no longer required.

When Larry sold the SFC, the engine had an Elettronica cylinder and head. Don't think he ever raced with that though. One of the later owners took the head from the bike and replaced it with a very nicely ported head (originally small valve, but with big 7mm valves, moved manifold studs etc.) which I guess was the spare head that Larry had flowed in US by Steve Ferree, but I'm not really sure about that.

Inside the head was a very nice lightened camshaft, very likely a Megacycle of unknown spec. I used the engine a few times until a retaining key snapped.

Next, I took that head and mounted it with a 6/C cam on my Segoni's SFC spec engine and put an original 1974 SFC head, that I still had on the shelf, on the Strung SFC.
Mounted the special cam and run it like this for 2 years now. That engine really flies.

Marnix
 
Not a lot of rivet counting going on there, Marnix. Love it!

The modded small valve head sounds similar to what I made for the SFQ - fundamental idea courtesy of Mr Phil Todd.

7mm stems, big inlet but std size exhaust valves. A lot of thought to the shape. I'd moved the studs for 10 degrees more incline (than a std big valve) and did the big grinding work to enlarge the ports to around the guides but the porting guru moved them again to achieve only 5 degrees from std big valve in order to get rid of dead air pockets in the port floor revealed when he ran it on the flow bench. I left the entire throat area to him. 5/C cam 3 degrees advanced. Certainly works!
 
Since Larry lobbed off the r/h crank end, and mounted a Pitsch/Kröber ignition there, it is not really easy to bring the bike back to stock condition, so I won’t. It’s a pure racer without dynamo, starter and battery and all unnecessary brackets removed. The wider very nice US made Sun rims are great too. I love it the way it is, and it’s my preferred track tool at the moment.

Marnix
 

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MarnixSFC said:
Since Larry lobbed off the r/h crank end, and mounted a Pitsch/Kröber ignition there, it is not really easy to bring the bike back to stock condition, so I won’t. It’s a pure racer without dynamo, starter and battery and all unnecessary brackets removed. The wider very nice US made Sun rims are great too. I love it the way it is, and it’s my preferred track tool at the moment.

Marnix
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I love that Larry prepared his SFC to race without the constraints of 'investment preservation'. It's what they were built for. I doubt there's a race-prepped factory SFC that hadn't been modified to improve it for its intended purpose.
 
For each race, the factory racers changed, sometimes for that specific track (racing without fairings in Barcelona), often to try to improve the machine (many different exhaust systems) or just to try new things (chain oiler in 1971). Sometimes changes were subtle, need to be a rivet counter to notice them. It’s my big fascination. 1973 was a top year in that respect.

Marnix
 
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