Del-orto carbs, help needed please

I have little faith in ultra sonic cleaners and gunged up carbs. Far better getting in with a very fine wire and a good blast of air to blow every thing through. Does the V50 have accelerator pumps within the main body of the jet assembly like the Big blocks? That will mess up your colourtune.I find the plugs on mine are always dark what ever I do. I just put it down to modern petrol, I have read that plug colour no longer works as an indication of the state of tune.Have you tried riding it yet? Does it pull away and ride smoothly?

Don

It doesn’t have the pumps.

I have tried riding it, and it runs, but soots up the plugs very quickly.

It is rich I assure you, they aren’t just black, they are sooty.

The colourtune is fine on tickover, but as soon as you lift the slides, even just a little, it goes to very rich.

Once off tickover, the mixture is controlled by the amount of fuel the needle lets through, and the amount of air the slide lets through.

I’ve had a call back for Reed Speed Scooters in Stourport upon Severn, which has been recommended to me as a del orto specialist.

They seem to know these carbs very well, they’ve suggested we check the air filter assembly , recheck what we’ve done, and if we can’t resolve the issue, they have full carb and test kit, and they estimate it’ll take about three hours to do both carbs and check everything on their dyno, but that’ll cost me just shy of £200 they guess.

They think the restriction is most likely in the air filter, as otherwise we’ve either been supplied with the wrong parts, ir we’ve made exactly the same mistake on both carbs, all are possible of course.

**** me for £200 i think you would near enough buy new ones from delorto
http://www.dellorto.co.uk/merchandise/Carburetor_parts.asp?CategoryID=2&PartsectionID=20

Have you read the Dellorto Tuning Guide?

I hadn’t Brian, but I have it now, many thanks

I had similar issues with the carburration on my 850-T3. I found that the float heights were wrong according to the Moto Guzzi manual (but correct according to Haynes).
I reset them to 23.5-24.5mm using a gauge made from a bit of thin card. When I reassembled the carbs it had transformed the bike. My plugs had been black but now they are coffee coloured and the adjustment screws on the carbs are really effective whereas before they did not seem to do very much.
All the best,
David.

my t5 would start from stone cold in the winter with no choke and blacken the plugs , as above was down to carb cleaningfew hours in the ultrasonic tank and a good blow through all the air ways and jet seats with an air line helped massivly but it still ran too rich mine turned out to be caused by the chokes failing to close fully, i swapped over to flip top chokes and never looked backPre ultrasonic cleaner days i would soak in solvent or redex for few days and keep moving them roundIf you disconnect the air cleaner pipes and carefull do a brief test ride does the engine run lean?Are you sure its running rich? rather than poor combustion or burning oil causing the sooty plugs?If you draw a blank with the carbs get the compresion checked

One thing I have found is Guzzis carburation is simple yet needs everything spot on. BUT they will run under many out of kilter tolerances.

Clean air filters
Clean carb
Good fuel
Good plugs and leads
The Chokes set and working correctly (Many have too little free play in the cables)

Then make sure the tappets are set correctly (Another big point of error here many I have helped with have been far too tight, I actuall cannot remember any I have helped with EVER being set too loose!!)

Make sure no leaks in the zorst system, another failing is tightening the header pipes too much crushing the gasket, once used to it you can feel the point the headers start to meet the resistance of the gasket.

Also make sure the open end of the exhaust rings are pointing downwards and slightly inwards that gap soon closes up when they get hot, they get hot real quick too

ONLY then can you go for a good run open it up get at least 30 miles under the wheels as long as it is feeling ok no obvious pops and bangs.

THEN check the plugs for fouling.

The unleaded fuel is NOT as good as the old 4* and does take some setting up REMEMBER the old manual for settings will NOT be quite correct for unleaded fuel, I forget which way it goes but make sure you have the settings for unleaded fuel when you set the timing and such.

Ah that is what I was referring to.

Going back to the air bleed inlets, it’s a very long shot, but it’s just possible that the air filter mounting to the carbs is covering or blocking them?

Matt at Eurocarb the Dell’Orto importer is extremely helpful - maybe worth giving him a call too and explain the problem.

Yep that’s who I spoke to not only very very helpful but parts arrived next day… fantastic service

First things first: please check your float levels.
All the best,

And that the floats are not filled with petrol. It happened to me.
Bought a new set of floats as the old ones were heavy compared to the spec (did a special trip to the Post Office to weigh them).A bit later it was running rich, and I found both new sets of floats full of petrol. They came direct from Eurocarb too.Brian UK2013-05-25 10:33:14

It does indeed appear to be the floats gentlemen, I’ll order some and let you know.

DOH!!! Didna fink o’ dat did I OK poss, also, needle valves could be leaking (?)

It is having new needle valves as well.

When I took the carbs off, petrol ran out of the engine side, there was our clue, no wonder it is running rich !

Great news. Be careful bending the arms on the floats when adjusting the height. They are very delicate. Slow and careful wins.
All the best,

Awl-righty then! If these are VHB’s, the info I’ve got is ~ If float weight is 10 grams, float height is 23.5mmIf float weight is 14 grams, float height is 24.5mm ‘float height’ means the distance from flat bottom of float to jointing face on carb body, that the float chamber seats on. Helps a lot to have a small piece of card with a cut-out in one corner that is 23.5 or 24.5mm long and say 10mm wide, you can then use that as a simple but quite accurate gauge. HTH

According to my book it’s supposed to be 14gm and 23.5mm.Check is done with carb upside down of course.