Dellorto floats

[Garry]

The RGS drives me crazy sometimes...
I have/had the problem that after driving for about five minutes, it would run on two cylinders and sometimes on just one. Because I’ve completely restored it and replaced or modified all sorts of things, I didn’t know where to start looking...
Eventually I got round to the Dellortos, where I replaced all the brass parts (jets etc.) and the throttle needels, as well as the floats.
The black 10g ones were no longer available and were replaced with the equivalent type 7450-01 in white.
When fitting them, I didn’t compare them with the old ones, only to discover that these are actually the right ones.
I swapped the floats back to the old black ones, and only then did I notice the differences.
Looking at the photos, does she get too much fuel with those white ones?
Which might explain why she then runs on just 2 or 1 cylinder?
After a short test drive, she does indeed run better and the exhaust headers are turning more brownish-blue.
A longer, more thorough test drive will show whether this was indeed the problem.

Does anyone have any experience with these white floats?

 

[sfcpiet]

What i was thinking - it has always been an alternative method for measuring fuel height. Are you serious that the new float bowls have no adjustability???

And yes, a very small discrepancy in float height can indeed spell 'bad things' DAMHIK.

As for WOT, why in hell wouldn't you be able to operate a Laverda at WOT??? I must be one seriously anomalous gent. In fact, I think I must know quite a few anomalous Laverda owners. The bikes didn't just suddenly become allergic to WOT throttle because a few decades had passed FFS.

Quentin,

The "new" white floats have a very different tang that acts on the valve. They sort of fit the old PHB/PHF and are not really meant to be adjusted, the adjustment range is extremely limited. Apparently made for a new variation of float valve.

The thickness of the sealing washer under the float valve seat alone has an enormous influence on float height, having a means of adjustment is paramount. The original Dellorto PHB/PHF service sets contain 2 almost identical fibre washers that fit under the float valves, they differ only in thickness and colour (to keep them apart). I've found many "overhauled" triple carbs with different washers fitted across the 3 carbs resulting in heights differing by as much as 3mm. Would have lasted about 20-25 seconds at WOT.

Lavs were made for WOT, it's in their DNA. Not using a Lav at WOT? Go buy a H-D... or Vincent?

piet

 

[Paul Marx]

Quentin,

The "new" white floats have a very different tang that acts on the valve. They sort of fit the old PHB/PHF and are not really meant to be adjusted, the adjustment range is extremely limited. Apparently made for a new variation of float valve.

The thickness of the sealing washer under the float valve seat alone has an enormous influence on float height, having a means of adjustment is paramount. The original Dellorto PHB/PHF service sets contain 2 almost identical fibre washers that fit under the float valves, they differ only in thickness and colour (to keep them apart). I've found many "overhauled" triple carbs with different washers fitted across the 3 carbs resulting in heights differing by as much as 3mm. Would have lasted about 20-25 seconds at WOT.

Lavs were made for WOT, it's in their DNA. Not using a Lav at WOT? Go buy a H-D... or Vincent?

piet

Put Amals on them. No need to worry about float level, just throw petrol in the bores.
Paul

 

[Vince]

Wasn't there an issue a while back about some fuel taps not flowing enough at WOT, some talk about adding a third fuel tap? It didnt get much traction as a story, pun intended

 

[Paul Marx]

Wasn't there an issue a while back about some fuel taps not flowing enough at WOT, some talk about adding a third fuel tap? It didnt get much traction as a story, pun intended

The same story goes around for a lot of motorcycles I think.
Same for Vincents, some recommend opening both taps for fast riding.

Be it on the Vincent, or the Falcone, which have two taps without reserve, practice is to use one tap and keep the other as reserve.

What would be the point of three taps on a single or a twin?

Paul

 

[MarnixSFC]

.

What would be the point of three taps on a single or a twin?

Paul

Early Egli Laverdas had 3 fuel taps, since they used the central tube as a second fuel tank.

Marnix