CLEMTOG said:
from Piets earlier posting
"Really don't understand what all the fuss hysteria is about with ethanol fuels."
I honestly don't know how you can say that Piet, I have been present when ethanol damaged float valves have been diagnosed and on one of those occasions it caused about 4 litres of raw fuel to drain into the sump oil, it ran out like piss, and the engine was running (just) on it, you just cant help thinking, hydraulic'd pistons and bent rods as well,and its not just the one bike either, my experience is more like five bikes, twins and triples but none of them my own, only last Decemebr I recovered from France a very expensive classic Masseratti Khamsin (150,000GBP) and it ran like shit, barley able to drive it onto my trailer, two months later it transpires that the float valve tips in the Webbers are shot,
and if there is no issue, why do Dellorto now provide float valves with revised soft tips of a different colour (red) (as do Webber)
CLEM
No pissing contest Clem, but Laverdas come and go here, a dozen bikes each month, in varying configurations, all quite happy to run on E5 fuels.
The red tipped float valves have been supplied by Dellorto since the early 1990's, no talk of ethanol in regular fuels yet. AfaIk, ethanol-containing fuels were re-introduced in Europe around 1998-2000. Whatever the reason for the Dellorto change, it wasn't the european swing to these fuels. Brasil, amoung other countries, were using alchohol-based fuels in huge quantities by then, maybe that was what decided it.
I've drained full-to-the-brim Laverda engines long before ethanol fuels were even thought of (IIrc, 23 litres was the record!). It's not a material issue, it's a design issue that lets fuel drain past the float valves. Due to the oblique angle of the carbs, especially on the triples, there is simply too much friction between float valve and valve body to allow smooth movement of the valve, or to allow the valve tip to seal adequately over a long period. The VHB carbs on the 750s e.g., do not have these issues, the float valves are close to vertical with a lot less friction involved. And these do not even have a rubber tip!
I overhaul loads of Dellorto PHB/PHF carbs each year and rarely do I find corrosion, certainly none caused by the fuel itself. I sometimes do find corrosion at the bottom of the float bowl, caused by accumulated water. But this can accumulate if the bike is left standing in rain or lives in an especially humid climate, not necessarily by water seperating from fuel. The fact that water is in there long enough and in a quantity to cause corrosion alone is an indication of how well a bike is maintained. Rubber components show mostly deterioration through simple drying out, pump diaphragms and o-rings are often bone-hard and brittle. I do find a lot of residue and gumming, but that had been a huge problem in pre-ethanol times as well.
Your Khamsin example isn't exactly very good Clem,
dodgy specialist engineering in abundance. How well was the vehicle maintained? The float tips were possibly shot well before the incident. Perhaps still working, by the skin of the teeth? There are bound to be as many expensive, polished turds in the classic car scene as in the bike scene, probably many, many more.
To illustrate my point, just today a rather tidy 3CL in close to original appearance happened to be brought in for a carb service. These had been repeatedly ultra-sonically cleaned and rebuilt, but the bike would stubbornly refuse to idle. Odo showed an original 23000km (in line with overall condition), the valves had been "done" 2000km prior to being
laid up parked at the back of the shed 20 years ago. An initial compression check showed below-par values, especially on #1. Checked valves, clearances all over the place. Corrected and another comp check, all a bit better and a lot closer to another. I found bowed inlet stub flanges, the o-rings had been replaced. The bowing was as much as 0.3mm, given the o-ring is squashed by less than 0.5mm, this was quite borderline. No problem, remedied on the lathe in a matter of minutes. Float heights all over the place, jets loose, needle and needle jets with a lot of fuel residue, no blocked passages. With a bit of fettling and a handful of odds and sods later, all seemed well. Three new (Champion
) plugs, hooked up the freshly-charged battery and it sprang to life. Up to now, I hadn't touched the balancing screws... balancing was way, way out. Another 5 minutes of fiddling and I had a steady 800rpm idle, on 95 octane E5 Eurosuper
. Strobed the original BTZ ignition, all OK, pleasant surprise. The dangerously low float heights were possibly the main culprits causing the erratic idling, but it was probably the culmination of all manner of little things. Just 'cos a Maserati may command 150000 quid, doesn't mean it's in reasonable condition. Many probably just look 150 grand good. You probably know full well how bloody expensive it is to keep a car of such calibre in top condition. What's a couple of float valves compared to the total complexity of that particular car?
What exactly was the diagnosed "ethanol damage" on the Laverda float valves?
piet
