Reassembling the Eldorado

[Freebirdbeachbum]

Thanks for the clarification. Have you checked what I asked above?

If it's the float level, valve clearances and timing, then yes. All check good. The left side fires right up and sounds fine. I went thru the carb again last nite, lapped the valve seat some more, and even ran it thru the ultrasonic again. Still a lot of gas in there and on the plug.

I'm considering getting a replacement carb at this point to either fix the problem or rule it out as the problem.

 

[scottmastrocinque]

I doubt you need a new carb.

The float is not adjusted correctly. it is obviously set to high therefore it never shuts off the fuel flow.

Do you have the specified distance set for the float? I don’t know what it is for this application.

 

[Freebirdbeachbum]

I doubt you need a new carb.

The float is not adjusted correctly. it is obviously set to high therefore it never shuts off the fuel flow.

Do you have the specified distance set for the float? I don’t know what it is for this application.

It measured 24mm on the nose. I'm going to swap it with the left side and see what happens. \

Table: Dellorto carburetor float height values

Carburetor	Float height, millimeters
PHBG	16 +/- 0.5
PHBL	24 +/- 0.5
PHBH	24 +/- 0.5
PHBE	18 +/- 0.5
PHF	18 +/- 0.5
PHM	18 +/- 0.5
VHB/Z/T	24 +/- 0.5
PHSB*	11 +/- 0.5
VHSA*	11 +/- 0.5
VHSB*	11 +/- 0.5
* PHSB/VHSA/VHSB one piece float assembly.

 

[john zibell]

Those specifications probably were designed for the black floats. If you have the white ones, then the level is too high as they are lighter. I suggest increasing the measurement about 2mm and see what happens no matter what color floats you have. One additional question, have you compared the weights of the two floats? If the one on the right is different from the left then you may have just found your answer. A friend of mine that works on BMWs has a tip scale to measure float weights. Since Bing never developed floats for ethanol fuel, they go heavy. He checks float weight on every airhead he works on.

 

[Freebirdbeachbum]

Those specifications probably were designed for the black floats. If you have the white ones, then the level is too high as they are lighter. I suggest increasing the measurement about 2mm and see what happens no matter what color floats you have. One additional question, have you compared the weights of the two floats? If the one on the right is different from the left then you may have just found your answer. A friend of mine that works on BMWs has a tip scale to measure float weights. Since Bing never developed floats for ethanol fuel, they go heavy. He checks float weight on every airhead he works on.

The floats are neither white or black but an olive drab color. Regardless, I swapped the left and right to no effect and then tried the old needle, also to no effect. Still nothing but the occasional pop.

 

[john zibell]

The floats are neither white or black but an olive drab color. Regardless, I swapped the left and right to no effect and then tried the old needle, also to no effect. Still nothing but the occasional pop.

Did you change the float level on the cylinder that isn't firing? I've never seen olive drab floats.

 

[Freebirdbeachbum]

Yes sir I tried that last. The only change was a tremendous backfire with a lot of smoke when I throttled it up. The floats are real Dellorto’s. I’ve got the same colored one on my Lodola.

 

[john zibell]

Yes sir I tried that last. The only change was a tremendous backfire with a lot of smoke when I throttled it up. The floats are real Dellorto’s. I’ve got the same colored one on my Lodola.

I'm beginning to suspect a defective carb body. I've seen that with Bings, but not on a DelOrto. I've got a pair of 30mm off a T-3 you could try (not sure if they would mount), or contact Amboman. He may have Eldorado carbs in his stock.

 

[Amboman]

The floats are neither white or black but an olive drab color. Regardless, I swapped the left and right to no effect and then tried the old needle, also to no effect. Still nothing but the occasional pop.

If you swapped the carbs left to right and it's still not running on the right side, then it doesn't sound like a carburetor issue to me.

The "olive drab" floats start out as grey when new and turn color after prolonged exposure to fuel.

 

[Freebirdbeachbum]

If you swapped the carbs left to right and it's still not running on the right side, then it doesn't sound like a carburetor issue to me.

The "olive drab" floats start out as grey when new and turn color after prolonged exposure to fuel.

I've swapped some of the internals with no luck so why not try the whole unit to either rule it in or out once and for all.

 

[Freebirdbeachbum]

I swapped the carbs and the right side came alive. I then swapped the slides and choke pistons separately with no change to rule out each of those so it appears that the right carb is bad afterall.

 

[Amboman]

Make sure all of the passageways are open in the carb body. thisoldtractor.com/moto_guzzi_loopframe_carburetor_rebuild_-__vhb.html

 

[Freebirdbeachbum]

Make sure all of the passageways are open in the carb body. thisoldtractor.com/moto_guzzi_loopframe_carburetor_rebuild_-__vhb.html

I did that no less than three times.

 

[Freebirdbeachbum]

Thanks to Amboman for referring me to Mark at Moto Guzzi Classics. Mark and I talked it thru and he nailed the problem. I had a main jet in the idle jet position which seems really obvious in hindsight.

 

[john zibell]

Thanks to Amboman for referring me to Mark at Moto Guzzi Classics. Mark and I talked it thru and he nailed the problem. I had a main jet in the idle jet position which seems really obvious in hindsight.

Easy to do on the square slide carbs. The round slide the thread sizes are different, pilot 5mm, mains 6mm.

 

[Freebirdbeachbum]

Easy to do on the square slide carbs. The round slide the thread sizes are different, pilot 5mm, mains 6mm.

I'm pretty sure this is my first carb rebuild where the designers didnt idiot proof it to ensure a mix-up like this wasnt possible.

 

[john zibell]

I'm pretty sure this is my first carb rebuild where the designers didn't idiot proof it to ensure a mix-up like this wasn't possible.

We all learn from experience. We gain experience from mistakes. The thing is to learn from them.

 

[Tonerjockey]

Way to hang in there!
Betcha THAT won't happen again.

 

[Amboman]

The Guzzi VHBs are the only ones that the idle and main jets are the same size. This is because they're the only VHBs with accelerator pumps built into the main jet assembly. On all the other VHBs, the main jet screws into the "bolt" that holds the float bowl on.

 

[Freebirdbeachbum]

Thanks one and all for your input and advice.