Balancing 750 Carbs

Seeing tiny drops of oil only just dribbling from the underside of the rockers at idle speed isn't exactly confidence-inspiring.  This oil mostly sort of finds its way to the valve tip... the rockers and cams are almost dry after only about 30 seconds.  I don't subject my valve train to such abuse if I can avoid it.  It is only at higher revs that oil flow increases.  Even then, pressure still isn't sufficient to squirt oil to the cam lobes, but is more or less splashed/flung around by the oscillating motion of the rockers.  The additional oil feed from the gallery above the cam at least delivers a couple of drops almost directly to the cam, may be the decisive drop between OK or knackered.

Reckon there weren't many traffic lights in late 60's Italy... :D

piet
 
sfcpiet said:
Seeing tiny drops of oil only just dribbling from the underside of the rockers at idle speed isn't exactly confidence-inspiring.  This oil mostly sort of finds its way to the valve tip... the rockers and cams are almost dry after only about 30 seconds.  I don't subject my valve train to such abuse if I can avoid it.  It is only at higher revs that oil flow increases.  Even then, pressure still isn't sufficient to squirt oil to the cam lobes, but is more or less splashed/flung around by the oscillating motion of the rockers.  The additional oil feed from the gallery above the cam at least delivers a couple of drops almost directly to the cam, may be the decisive drop between OK or knackered.

Reckon there weren't many traffic lights in late 60's Italy... :D

piet
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The oil hole in the rocker pin is also a great place for small flecks of reconstituted cam chain tensioner roller to congregate, and this is greater cause for concern (assuming your top cover isn't causing the flow past the two middle front studs to be restricted in any way). Unfortunately the rocker pins can't be removed with the engine assembled (and in the frame) unless you remove the outer long studs, otherwise i would make checking and cleaning the rocker pins a job for every oil change or two.

IMHO the extra drilling the factory made in SF2/3 heads only serves to reduce that meagre flow at idle even more. I drilled my SF1 head after seeing the factory 'upgrade' but decided to block those holes at my next top end overhaul. Have had no problems.

My heavy SF1 rockers did over 100,00km before I went for the lighter later model ones and fitted a 5C cam - the rockers were still in decent nick. Now that I'm going to run a double row SF oil pump (12mm vs 6mm) I'm hoping that trickle will be a stream! I also swear by top quality synth old like Mobil 1 (for moto wet clutch motors).
 
When I have run the motor to check oil flow to the top end, even at idle there is oil flinging around all over the place, so I haven?t experienced that which Piet has seen. I will NEVER assemble an SF head without bits of wire to prevent the studs blocking that oil channel though. My cams come out perfect and the followers are the ones that I fitted way back when I discovered the problem with my motor, which ate IIRC four cams and sets of followers in two years chasing the cause, I was even test riding new bikes, it was a nightmare. An inline oil filter would prevent debris from getting stuck in the rocker arm holes, would be a good use for the oil cooler lugs that are blanked off on my street motor.
As for carb synch, I just get it dead even on both cylinders at idle, then ensure that they pick up off the stops exactly the same. If they are a mm off at WOT it means absolutely nothing, compared to one cylinder opening after the other when coming out of a corner. Do people who set up multis with vac gauges then go and check them with drill bits and stuff afterwards so that they can gribble over the difference between the vac gauge and slide height?
 
Tippie said:
When I have run the motor to check oil flow to the top end, even at idle there is oil flinging around all over the place, so I haven?t experienced that which Piet has seen. I will NEVER assemble an SF head without bits of wire to prevent the studs blocking that oil channel though. My cams come out perfect and the followers are the ones that I fitted way back when I discovered the problem with my motor, which ate IIRC four cams and sets of followers in two years chasing the cause, I was even test riding new bikes, it was a nightmare. An inline oil filter would prevent debris from getting stuck in the rocker arm holes, would be a good use for the oil cooler lugs that are blanked off on my street motor.
As for carb synch, I just get it dead even on both cylinders at idle, then ensure that they pick up off the stops exactly the same. If they are a mm off at WOT it means absolutely nothing, compared to one cylinder opening after the other when coming out of a corner. Do people who set up multis with vac gauges then go and check them with drill bits and stuff afterwards so that they can gribble over the difference between the vac gauge and slide height?
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Vacuum guage readings sometimes don't concur with slide heights.  Inlet vacuum is also largely dependant on valve clearances, especially at low revs.

I don't even start synchronising carbs without first checking/adjusting valve clearances.

I cannot detect any wear or tear on my cams and rockers after 60000-odd km with my modified pump.  Idle revs give a nice flow at the rockers, with oil flying everywhere almost imediately after start up.  But worn, stock pumps usually deliver no more than a dribble.
piet
 
You don't say, I spent 18 months trying to find where my off idle power had gone in my Pantah after I bought a new set of vacuum gadgets.My old mercury gauges had developed bubbles so I bought a set of rod style ones. They worked great on the 3C but as I said the Pantah needed to be revved like a drag racer to get away off idle.I eventually found the slides were 5mm out of sink via vacuum, done with a drill bit it became much more tractable.
 
Simple thing is drop the carb slides on to a Hex Screw Driver adapter and work from there.

And Listen - Sync your throttle cables first  ;o)
 
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