E: Engine Egli 500 Special Carburation

[Bill Thomas]

I found with Dellorto 36mm Pumper type, The main jet size is smaller than we are used to with other Carb's.
I was only running 165 main jet when timed at over 140 mph on my Vincent Special Road Bike.
I also had to use the float valve out of a 40mm type Carb' to pass enough petrol above 110 mph.
I bought a Moto Guzzi hand book to get an idea of what jets I would use.
If anybody knows what Bike would use Ben's Non Pumper type Carb, That may help.
I would take a File to Ben's Slide !!, But only if I had another one !!.
Cheers Bill.

 

[vibrac]

I found a lot of the dyno shops here wont look at old bikes with carburetors, even when I jokingly said to the chap at the counter that I could change jets, slides, idle mixtures and float levels probably faster than he could alter the settings on an injected modern, he laughed and said "Sorry........ Not interested".............

That attitude shows they are not the sort of shop you want anyway it is best to get a plug for a sensor in the exhaust pipe I did start with a probe up the exhaust but a plug position nearer the head is better
We were sorted in an hour by a shop in Buckinghamshire the boss does modern racing so he is a belever and just loved the old Vin
See the old thread 'stock comet on the Dyno' for a vid of him at full throttle!

 

[van drenth]

Actually here is a plug (2 plug head)
View attachment 23395

I run als on mine blackshadow

So I'm back in the garage trying to get the Egli riding well out on the road (where I am desperate to be). With school holidays rolling (I'm a teacher) I'm pleased and ready to get this sorted (when not so busy with my two sons). The great news is thanks to the help here in the club the oil system is sorted and running as it should with special thanks to Marcus. The not so good news the bike simply doesn't go as it should and is an absolute pig to start. I spent over an hour getting started yesterday.
I took the NGK plugs out and replaced with new brisk LOR17,s which I had hoped would be better, well I ended up putting the NGK's back in amongst other checks and a lot of kicks!
The running symptoms are (once started)!
Idles fine after a minute or so
Pulls away fine if a little lumpy
Acceleration is fine
Absolute pinned full throttle seems fine
Part throttle any position other than flat out terrible, surges forward, drops to nothing then surges again, it's like flicking the throttle or running out of fuel but plenty of fuel (50/50 avgas and super plus) and steady part throttle.
For normal cruising/riding it is terrible

In my limited knowledge I feel it's a problem with the carb Dellorto PHBE 34. I have taken it apart several times to clean it out but been unable to remove the float bowl pin to clean parts beneath. Jets are clean.
The picture below shows carb and jet sizes, do the sizes look right? Any ideas please?
View attachment 23392

on this type dellorto leaks are common at the choke valves, IN CLOSED POSITION, so it starts oke but after warming up the eratic running starts. got same problem at mine black shadow.

 

[greg brillus]

Plunger rubbers deteriorating from the modern fuels perhaps.

 

[Normski]

Plunger rubbers deteriorating from the modern fuels perhaps.

On my Guzzi, in which I have sometimes used E10 - 10% ethanol fuel I haven't had any detioration of the choke plunger rubbers which I could blame on fuel. Mostly they indent or get hard with age. They are cheap from Dellorto in Reading UK (formerly Eurocarb) and I do change them out from time to time. It's important to make sure they seat properly i.e. have slack in cable if cable operated. The plungers are quite a tight fit in the bore of the carb and can stick if dirty or corroded. A smear of copper grease helps.

 

[Bill Thomas]

I think I asked Ben to check those a long time ago, Just in case, Mine have been fine for 40 years, I checked them this year. Cheers Bill.

 

[van drenth]

Plunger rubbers deteriorating from the modern fuels perhaps.

ethanol residu's and it will not close properly.

 

[Ben Langton]

Evening, I had a long and interesting chat with Steve A’Lee at GT Motorcycles. A good start to the conversation was that he has worked on classic bikes (classic racers too) before, Vincent’s and new what an Egli was. He said the club had a couple of days of tuning in the past Glyn Johnson.
Anyway I will be getting a few jets and he said he could work on the slide if needed. Going to visit in the new year.
Will keep you posted.