New Guzzi (to me), long drive & Carburetion

[not-fishing]

My youngest son and I made a road trip over the weekend.  We picked up an 82 V50 III in decent shape with low mileage (12,500).  Of course being a bit of a nut we drove 1600 miles round trip in 35 hours.  I find I need to nap more than I did 30 years ago on Road Trips

Of course we only stopped for gas, potty breaks and naps -- a true Road Trip.

My Guzzi Carburetion question is there's a part throttle hesitation at less than 1/4 throttle possibly in one cylinder.  The V50 has had the carburetors rebuild but I'm thinking the culprit is really the dammed EPA (lean jets) and the universal cone type air filters the V50 has on it.

I'm going to try the carb balance and air-fuel screw adjustment but I was thinking that a better solution would be to get a set of Monza jets (which look like the next size up) and rejet the Carbs to Monza specs.

What say all ye small block tuners about Monza jets?

[Triple Jim]

If it were mine, I'd put a piece of tape on the twist-grip handle, marked from zero to full throttle in 1/8 throttle increments, and mark a pointer on the casting.  Then when it hesitates, note the position accurately.  That will tell you which circuit of the carb is causing the problem. 

Less than 1/8 is usually the pilot circuit.  1/8-1/4 can be the cutaway (round slides?) or needle position, for example.  If it's really only one cylinder, you might have a clogged pilot circuit on that side, and a careful cleaning would be the solution.

Great bike, not-fishing.  I've thought about trying to get one myself.

[SED]

The workshop manual and Guzziology suggest that the v50III and Monza jetting are the same.

My Monza has 50 slides, x-6 needles, and 268 needle jets which correspond to Euro jetting according to Guzziology.  I didn't change jets (so didn't write them down) but the other parts suggest stock Euro jetting.  This is the way I got it  and I don't think anyone had changed it because it still had stock airbox and plastic fuel banjos so no one had worked on it much.  Yours may have the "Euro jetting".

Two things to consider - the air filter arrangement and the auto advance.  Mine runs great with stock jetting and the stock airbox and paper filter.  (though it seems to run too rich at high altitude)  In contrast my LMIII has pod filters and it pops through the carbs unless it has larger than stock idle jets.  (stock is supposed to be 50.  55 is still too lean so it's running 65s.  Haven't found 60 idle jets to try yet)

The auto advance unit was all screwed up when I got my Monza and it had a terrible hesitation. 

A final thing.  If the hesitation is accompanied by a pop through the carb, check the throttle cable balance.  The plastic twist grips with their goofy plastic quick release distort under spring pressure and I was never able to keep the carbs balanced until I replaced them with cast aluminum throttle controls (on both bikes!).

Hope this helps!
Shawn

[Chuck in Indiana]

^^^^^^
That pretty much covers it. Just for giggles, though, adjust the valves, too.

[not-fishing]

Many thanks,

I'd ordered the manuals from Harpers on the V50 and also a copy of Guzziology from Moto International.

I've been able to see from close, "post buy", inspection that the V50 has been "restored".  All the hoses and cables have been replaced, the brakes are new but the some of the engine bolts are rusty and there's "flowlines" of that white oxidation present on the engine.  Points are new.

I've lubed up the switchgear (wd40) which works great now and pulled the side covers to look at the carbs.  The oil looks new.  Tire air pressure was low but the tires are new Avons (I have to check the year).

Brakes are new but the's a throb when using the single front, rust on the left rotor, so I figure I have to pull the rotor and have it turned.

I guess I'll need to start posting pics.

This wouldn't be much of a deal except I'm resurrecting an '82 Peugeot 504 Turbo Diesel Wagon that I recently inherited.  I had to drag it out of the back yard onto the trailer because the brake were locked up.   I'm in the process of new rear brakes, rebuilding front calipers, fixing all the door locks so that the doors open, lube everything, replacing the worthless side window belt weatherstrip, replacing the battery and cables.  The clutch feels heavy and bad but until I get the engine started I'm not worried about it.

Just the initial repairs.

Also just to be clear the Peugeot RAN WHEN LAST PARKED