Primary Chain adjuster shoe wear.

+1 (bigthumb)  He retired recently didn't he? Did the business die or did he hand it over to someone?
 
I've already learned the hard way.
The chain rupture happened at 180 km/h at 7,500 rpm when I shifted from fourth to fifth - not funny.
Brettoni told me he had several times the same experience. A maximum of 10,000 km is a must for the SFC.

My recommendation:
- normal 750 + correct oil change: change chain each 50,000 km
- sporty driven SFC or tuned 750 + correct oil change: change chain each 10,000 km

Chain:
switch to two high-quality reinforced single chains (same charge)! E.g. from OCT.
You have four connecting links each, but the one by the single chains are much stronger.

toothless  :-X
IMG_1057.jpg


Better:
iPhona5_606.JPG


Thomas aus LAU
 
AndyW said:
+1 (bigthumb)  He retired recently didn't he? Did the business die or did he hand it over to someone?
Click to expand...

Now in the hands of Jason...    https://the-chain-man.co.uk/
 
Thomas aus LAU said:
I've already learned the hard way.
The chain rupture happened at 180 km/h at 7,500 rpm when I shifted from fourth to fifth - not funny.
Brettoni told me he had several times the same experience. A maximum of 10,000 km is a must for the SFC.

My recommendation:
- normal 750 + correct oil change: change chain each 50,000 km
- sporty driven SFC or tuned 750 + correct oil change: change chain each 10,000 km

Chain:
switch to two high-quality reinforced single chains (same charge)! E.g. from OCT.
You have four connecting links each, but the one by the single chains are much stronger.

toothless  :-X
IMG_1057.jpg


Better:
iPhona5_606.JPG


Thomas aus LAU
Click to expand...
Was that downchange intentional Thomas?
I worked deliberately when racing to make downchanges when the revs had dropped enough, very easy to drop down too early. I know of several motors blown due to that.
Edit: oops, thought you had said 5th to 4th.
 
Tippie said:
Was that downchange intentional Thomas?
Click to expand...

After I had planned to take part in a small local city race the next weekend, I wanted to test whether the SFC was "fit" on the way, home from a Laverda meeting in northern Bavaria.
Usually the SFC Electronica has to manage about 220 km/h (not speedo-sight => GPS!).

To do this, I turned onto the autobahn and accelerated up to 7500 rpm and then switched to the next higher gear.
Exactly when changing from 4 to 5 the chain broke. The rear wheel hadn't locked.

Brettoni said, this is due to the lighter crankshaft where higher alternating forces occur.

Thomas aus LAU
 
Tippie, your twin simplex chains, pictured above look much heavier than the three that I saw broken, do you know what make and type they are, the ones being supplied (in the past) by UK outlets look more like bicycle chain in comparison.
CLEM
 
CLEMTOG said:
Tippie, your twin simplex chains, pictured above look much heavier than the three that I saw broken, do you know what make and type they are, the ones being supplied (in the past) by UK outlets look more like bicycle chain in comparison.
CLEM
Click to expand...
Thomas?picture Clem. Mine are Jwis, supplied by Andy before he retired. They are also very heavy duty, might be able to find a pic if you want. I also got a sinlgle row to use as cam chain on my SF race bike, if I decide to, and that one, same pitch, is not as heavy duty as the primary.
 
no need Tippie but thanks, I am still using triplex, cant seam to wear them out, and I still have some new unused ones.

The historical twin simplex chain failures is probably before dealers got wise as to what works and what doesn't, when triplex were in short supply (they never were if you looked a little harder, NOS and good quality replacements) plus 10 or more years ago those bikes were getting longer and harder  use than they get today.

CLEM
 
My SF3 came with 2 simplex and terribly noisy. One was stretched more than the other so I got a duplex from The Chain Man, Iwis I think. Apart from the exhausts a lot quiter now.
 
Nat Magee said:
My SF3 came with 2 simplex and terribly noisy. One was stretched more than the other so I got a duplex from The Chain Man, Iwis I think. Apart from the exhausts a lot quieter now.
Click to expand...

Same experience.
Twin chains are noisy and cannot be tensioned to reduce noise, probably due to uneven stretch.
I've been using the Mercedes cam chain duplex for quite a while now in my SF2. One will be going shortly in the 3C I'm restoring.

Paul
 
Paul Marx said:
Twin chains are noisy and cannot be tensioned to reduce noise, probably due to uneven stretch.
Click to expand...

If the stretch is uneven, then I reckon you only have one single drive chain (the tighter one). The loose chain is a freeloader that's doing nothing other than flapping around, soaking up energy and making noise.

Same as Clem - I'm still running a Regina triplex on my Jota and have a new IWIS as a spare. The previous owner put a new Regina on it when they were still available. The bike hasn't done a lot of miles since.

I bought the IWIS triplex from the man himself (Andy) at a Stafford classic bike show while on a trip to Pommyland in 2009. At the time he said it was from the last bit of good IWIS triplex left in his stock. It was no longer being made and he had been unable to find any more old stock. He reckoned once his IWIS was gone, that would be the end of good triplex replacements. He held up the remaining length of chain and it didn't reach the floor. I reckon there would have been enough for 2 or 3 primary chains left. He said it would probably be all gone by the end of that bike show because Vincents use the same chain and the Vincent owners club guys were circling like vultures. That's about the time he started recommending the Merc duplex.
 
for shoe wear suggest a cobbler would be very helpful I have issues with the heals of my boots wearing out over time so once a year they go back to the factory in SA for a retread  8) 8)
 
Brett said:
for shoe wear suggest a cobbler would be very helpful I have issues with the heals of my boots wearing out over time so once a year they go back to the factory in SA for a retread  8) 8)
Click to expand...
In SA eh, would that be Twiggys latest purchase at a cool 200mill?
 
Pls. note, that the simplex chain is available as roller chain with a 3,31mm pin, and, as bush chain with a 4,44mm pin.

IIrc Andy (Forsdick) did always recommend the 4.44mm (e.g. IWIS G67HP) for use on primary drives, and, so does Steve B (Breganzane) on his excellent summary page he did for Laverda primary chains.

So in case two simplex chains caused any trouble it should be worth knowing which derivative (3,31mm or 4,44mm) is talked about.

The Mercedes duplex chain is also a 4,44mm big pin bush chain (IWIS D67HP).

Cheers
Jo
 
let us not forget that the '70s CB750 Honda (first type) had twin simplex primary chains, with a common tensioner,but buried in the centre of the four cylinder motor, that embrassment to Honda as their were lots of failures and causing massive engine damage either simultaneously or later when repaired, due to stresses and remaining swarf. They quickly changed the design, but then that was with (possibly) different chains to that we see now.
CLEM
 
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