phil37
Hero member
- Location
- Lincolnshire
Triple conrod peace of mind check.
- Thread starter jdugen
- Start date
Simonr501
Hero member
- Location
- Lympne, Kent. UK
Greg Parish said:
Ok, we give in! That is the best bent conrod by a mile.
Yogi,
The problem I had with the white floats was swelling, such that they wouldn't pivot on the mounting shaft.Cured by taking a craft knife to them, but not exactly what you'd expect...maybe a modern fuel thing, I dunno. Keith binned them anyway, without discussion, as he doesn't like them, it seems with good reason.
The problem I had with the white floats was swelling, such that they wouldn't pivot on the mounting shaft.Cured by taking a craft knife to them, but not exactly what you'd expect...maybe a modern fuel thing, I dunno. Keith binned them anyway, without discussion, as he doesn't like them, it seems with good reason.
jdugen
Junior member
- Location
- Manchester UK
Hi all.
Although this is my first Laverda, I'm no stranger to motorcycles, my first was a Ducati 250 way back in 1965. I know that owning most examples of the generations since does not qualify me as a de-facto 'expert', far from it, but I do know my way around the things. (I could go into the total re-design of my CB77 to eradicate all its faults, the Laverda engines being very similar in design). My observations are just that, comparing my experience of other designs to this one for the groups consideration, comments and suggestions.
So, to the point. The float bowls are indeed quite large, but not in total volume when the internal castings are considered AND the angle they sit at means at least a third of that volume is just air. This impacts on the floats ability to open and close in a controlled manner. To ensure the correct volume of fuel actually above the main jet (this set to the rear of the bowl, in the 'shallow end' as it were), means that the fuel level has to be set quite high at the front of the bowl, actually not too far from the bowl / carb body joint. This is the area of fuel supporting the floats. Because the floats are circular (and the bowl bottom flat), there is little actual room for the floats to move through the arc between fully open and shut when set to the right fuel level. The white floats as delivered, with the small metal tang horizontal, don't even begin to close the needle valve. The one that has settled to the right level has the tang bent at nearly 45 degrees, miniscule adjustments of the tang up or down have a dramatic effect on fuel level. I consider this method of fuel level adjustment to be ridiculous. (I have made up a float bowl with an external clear pipe fed from the bottom of the bowl, I can see exactly where the fuel level is, much like the clear plastic bowls that were available). The 47 - 48 milli-litres that is specified as the correct fuel amount brings this level to a few MM below the bowl front edge.
More worrying, is that an empty bowl takes over 30 seconds to fill to correct level. I am pretty certain that the floats do not open the needle valve fully when the bowls are empty, basically because the bottom of the float is held up by the floor of the float chamber. With a flat profile to the base of the floats, they would be able to swing much further down into the bowl allowing a faster fuel flow. As I have said previously, these white floats are a royal pain to set-up, the black ones do allow for a lot more fine adjustment, but even they are finiky.
As to just riding it and sacking the psychiatrist........ I would if I had money to burn and the supply of crankcases was infinite. As it is, both money and crankcases are very definitely finite!!! A bit of time and a few gaskets seems like a no-brainer to me....?
Although this is my first Laverda, I'm no stranger to motorcycles, my first was a Ducati 250 way back in 1965. I know that owning most examples of the generations since does not qualify me as a de-facto 'expert', far from it, but I do know my way around the things. (I could go into the total re-design of my CB77 to eradicate all its faults, the Laverda engines being very similar in design). My observations are just that, comparing my experience of other designs to this one for the groups consideration, comments and suggestions.
So, to the point. The float bowls are indeed quite large, but not in total volume when the internal castings are considered AND the angle they sit at means at least a third of that volume is just air. This impacts on the floats ability to open and close in a controlled manner. To ensure the correct volume of fuel actually above the main jet (this set to the rear of the bowl, in the 'shallow end' as it were), means that the fuel level has to be set quite high at the front of the bowl, actually not too far from the bowl / carb body joint. This is the area of fuel supporting the floats. Because the floats are circular (and the bowl bottom flat), there is little actual room for the floats to move through the arc between fully open and shut when set to the right fuel level. The white floats as delivered, with the small metal tang horizontal, don't even begin to close the needle valve. The one that has settled to the right level has the tang bent at nearly 45 degrees, miniscule adjustments of the tang up or down have a dramatic effect on fuel level. I consider this method of fuel level adjustment to be ridiculous. (I have made up a float bowl with an external clear pipe fed from the bottom of the bowl, I can see exactly where the fuel level is, much like the clear plastic bowls that were available). The 47 - 48 milli-litres that is specified as the correct fuel amount brings this level to a few MM below the bowl front edge.
More worrying, is that an empty bowl takes over 30 seconds to fill to correct level. I am pretty certain that the floats do not open the needle valve fully when the bowls are empty, basically because the bottom of the float is held up by the floor of the float chamber. With a flat profile to the base of the floats, they would be able to swing much further down into the bowl allowing a faster fuel flow. As I have said previously, these white floats are a royal pain to set-up, the black ones do allow for a lot more fine adjustment, but even they are finiky.
As to just riding it and sacking the psychiatrist........ I would if I had money to burn and the supply of crankcases was infinite. As it is, both money and crankcases are very definitely finite!!! A bit of time and a few gaskets seems like a no-brainer to me....?
- Location
- Calgary, Alberta, Canada
as far as actual fuel flow volume, there are five different sizes of float valves, ranging from 250 to 400, all the same price. If you figure fuel flow is too "slow", go for a bigger float valve. http://www.dellorto.co.uk/merchandise/products_details.asp?PartNo=8649&CategoryID=2&PartsectionID=51
as for the white floats, having apparently identified an issue with them, don't use them, go back to black floats, used if necessary.
then you can look at fuel feed line i.d. to the carbs, a fuel balance tube to feed the three carbs equally, the fuel flow through the petcocks, and the venting of the fuel tank.
it certainly does not hurt to level the carb rack a bit more using angled manifolds, various manifolds have been tried, Triumph triples, snowmobile, Red's 15 degree manifolds, etc, all of which usually mean it is then a tough connection to the stock airbox, but frankly the angled manifolds don't seem to make much of a difference. The angled manifolds do make it easier to fit the taller Mikuni RS flat slides though.
I actually had an RGS rod bend from hydraulic lock caused by fuel leakage through the float bowls into the cylinder so I have considerable sympathy for your quest, it isn't inexpensive to rebuild a Laverda triple crank with Carillo rods and new bearings, ALWAYS turn your fuel petcocks off when the bike is not in use....
Paul LeClair
as for the white floats, having apparently identified an issue with them, don't use them, go back to black floats, used if necessary.
then you can look at fuel feed line i.d. to the carbs, a fuel balance tube to feed the three carbs equally, the fuel flow through the petcocks, and the venting of the fuel tank.
it certainly does not hurt to level the carb rack a bit more using angled manifolds, various manifolds have been tried, Triumph triples, snowmobile, Red's 15 degree manifolds, etc, all of which usually mean it is then a tough connection to the stock airbox, but frankly the angled manifolds don't seem to make much of a difference. The angled manifolds do make it easier to fit the taller Mikuni RS flat slides though.
I actually had an RGS rod bend from hydraulic lock caused by fuel leakage through the float bowls into the cylinder so I have considerable sympathy for your quest, it isn't inexpensive to rebuild a Laverda triple crank with Carillo rods and new bearings, ALWAYS turn your fuel petcocks off when the bike is not in use....
Paul LeClair
Tom Eatman
Hero member
The new white floats have a completely different shape than the older ones so the baseline measurement of 18mm from the top edge of the float to the edge of the carb body doesn't work. No idea what the white ones require, I normally re-use the tried and true old ones so I'm not adding new variables into the equation. The Dells work perfectly fine if the basics are set properly.
Tom
Tom
Simonr501
Hero member
- Location
- Lympne, Kent. UK
Ha ha, more folded, but I get your point.