what kills con rods?

SFC 750 rods..

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Piet, I can confirm the Carillo rods will run for a looong time tweaked. My 750 F1 Ducati racebike had a number of piston disintegrations in its life before I got it. I discovered [after two seasons of racing,10k redline] that the wristpin wouldn't go through both holes with the rods side by side on the crank. Close inspection revealed approx. .25mm misalignment on the vert. small end. It also explained the blowby on the left side of the piston! I sent the rods to Carillo to see if they could be straightened/refurbished and for about $200 I got my rods back as good as new. I should add that they were new in 1988 and are still in use. 
 
I've had a lot of Carillos through my hands over the years - though not so far any for a Laverda...They used to specify a life in hours for their rods when you bought them. They also used to offer a service whereby you could return the rods and they would normalise, re heat treat and rebush/resize them.

Keith, Shiny....very impressive. I personally prefer to see a nice dull surface these days...shotpeened after polishing.
 
For some reason, with all the bikes I've ever owned, I have always turned the taps off, way before you blokes scared me shitless with stories of bent conrods and aerated cases. :(
 
Learnt my lesion on a 64 Bonnie,went to start it and couldn't kick it through,completely full of fuel,top and bottom
 
I even turn them off roughly 500 meters before I get home. This makes sure the float bowls get fresh gas when I turn the fuel tabs on next time. Better starting, no issues.  :-*
 
Laverdalothar said:
I even turn them off roughly 500 meters before I get home. This makes sure the float bowls get fresh gas when I turn the fuel tabs on next time. Better starting, no issues.  :-*

Lothar, excellent advise..like a airplane pilot doing the checklist coming in for a landing..I do the same thing..fuel off right side..check..fuel off left side..check..gearchange..park the bike..let it idle for a minute,check..lights off..check...ignition off..check.

Only problem is you need to wait a short period of time once restarting to allow the floats to refill...so the drill is...turn petcocks on, check..inspect the the chain, bike and controls to be sure nothing has loosened, check...as a habit..glance under carbs (no fuel float bowl leaks), check, put on helmet and gloves..start bike.

 
there are numerous posts on the triplesonline forum (our brothers on BSA/triumph triples) about what the right moment is to cut off fuel before coming home. Apparently some guys ran into trouble with their pistons rings and hone by closing off too early. Their advantage is also that they've a prime button on the amals to refill the floats.
 
None the less, the open taps doeas not explain why the rods let go at 4K RPM.


As an aside I had a 72 Pantera with 4 2 barrel downdraft weber carbs. I went to start it and sure enough hydro locked. Fuel leaked past the floats. No taps to turn off there.
 
It only takes roughly 5 seconds to fill the floats from completely empty to full if everything goes right. So - no need for a tab to fill them, just open the fuel taps before you put on helmet and gloves and you can start the bike right after you are fully armored.  ;)
 
I've been having this 'discussion' over on the 'other' forum.  (Where the idea of conrod damage from fuel lock was pooh poohed.....)
My recently acquired Jota was merrily dumping its fuel straight into the barrels, new float needles immediately ordered, but....
Surely the problem is the lack of overflow venting on the Del Orto's?  Inspecting my set, there is nowhere for the float chambers to drain other than the cylinders.  Mine now have a judicious 5mm hole drilled into the float bowls just above ideal fuel level.  Serves two purposes, allows exact setting of fuel level in the floatbowl, and any overflow goes out down the pipes to the floor.  (Just as every Jap carb has had since they were first designed).  (Doncha just love Italian engineering).
 
Surely the problem is the lack of overflow venting on the Del Orto's?  Inspecting my set, there is nowhere for the float chambers to drain other than the cylinders.  Mine now have a judicious 5mm hole drilled into the float bowls just above ideal fuel level.  Serves two purposes, allows exact setting of fuel level in the floatbowl, and any overflow goes out down the pipes to the floor.  (Just as every Jap carb has had since they were first designed).  (Doncha just love Italian engineering).

All floatbowls must be open to the air somewhere or the carb wouldn't work.  Jap carbs often have drain hoses, but that has nothing to do with overflow.  There's a good reason why there was a move to vacuum operated taps in the last year of carburetted bikes.
 
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