Clogged carburetors are a common ailment for older motorcycles, and vintage Moto Guzzis are no exception. The stock Moto Guzzi square slide (VHB) carburetors by Dell'Orto are very durable and easy to maintain once they've been properly cleaned and rebuilt. With a minimal amount of care, a restored carburetor should last the life of the engine.
If your Guzzi hasn't run for a long period of time, there is a chance that your carbs have been filled with stagnant fuel; which eventually dry and "gum up the works." Over long periods of sitting idle, the lighter components of gasoline tend to vaporize, leaving the heavier particles behind, resulting in gum and varnish. When you pull the bowls off your carburetors and discover something resembling dried-up maple syrup, definitely send them in for Cycle Garden's full carb rebuild.
Guzzis tend to run better on fresh high-octane "super unleaded" gasoline. So before you go through the trouble of sending in your carburetor, make sure your fuel taps are on (it happens), and check them for clogging. We strongly recommend making a habit of turning your fuel valves off when powering down your motorcycle.
If you've noticed that your throttle doesn't respond like it use to - if it begins to sputter or misfire - chances are you've collected some gum, dirt or rust. Dirt & contaminated fuel can also result in:
Some of these simple carb issues can be resolved with a cleaning of the fuel tank, petcocks/valves & fuel banjo screens.
We clean carburetors with a combination of high-pressure air & industrial grade solvents. We have all the correct Dell'Orto replacement parts on hand, in case you wish to simply order them. If it gets too tricky, you can always send your carburetor to us via UPS.
1. Examine the atomizing nozzle for wear (which dangles from the slide)
2. Check the main brass jet and pump assembly for signs of wear or damage
3. Inspect each needle & jet, for dirt, debris, proper size, as well as damage
4. Make sure jet passages in the body are clear
5. Blast the outer casing with walnut shells
6. Re-polish the aluminum slide caps and carb bowls
7. Replace hardware with re-zinced parts (for an extra charge) to really make your Dell'Orto carburetor look brand new. See Zinc & Cad Section
8. Fine-tune throttle cable adjustment & balancing
9. Switch out O-rings & seals
For long-term storage, our first recommendation is to run your carbs dry to prevent varnishing. It's simple and very effective.
An alternative method is to treat the fuel with a stabilizing fuel additive. Start by pouring in the recommended amount of fuel stabilizer and running your bike for at least 10 minutes to ensure the mixture has traveled the entire system.
A third option is, of course, to drain the fuel, remembering to coat the inside of the tank & carburetor with oil. Otherwise, you may experience internal rusting & corrosion.
Whatever carb issues you may be having, we at Cycle Garden deal with Dell'Orto Carb Systems on a daily basis. We can solve your problem, and get you and your carb back on the road, breathing fresh air - the way nature intended.