Carburetor cleaning

cheese monkey

Active Member
Hi chaps, got two carbs on my Guzzi. It was running reasonably well before I had it and has not run now for about 3 years. Externally the carbs are pretty filthy, internally I dont know. I have fiddled with carbs in the past but I really am not keen on the idea of doing anything again. Do you think it is worth getting them ultrasonically cleaned? There is a place near me that does it for 45quid each carb. I'm thinking they will be sure to run, they will look nice and will give me a good base for any tuning required. On the other hand it might not be necessary and it costs a fair amount of money.
 
Make sure that they fully disassemble the carbs. Many shops just throw them into the bath and hope for the best.

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Cleaning is a waste of time without new fuel filters and cleaning the rest of the fuel system. Empty the tank, derust it, coat with 2stroke oil to prevent flash rust, and fill with treated 100% gasoline. Ultrasonic cleaning is not magic, but if done properly is probably the best method to clean internal pasages fully ONCE THEY ARE OPENED.
 
Yes very important point.Make sure youre Tank is clean.

On my last project I gave the carbs to a professional carb guy who was doing this for decades.
They came back nice and clean,but since i´m anal about everything I took them apart again to see how meticulous he worked.

I tapped out the needle jets and found that they were FILTHY and filled with sand (seemed to be some kind of material that was used in the ultrasonic cleaner).

My advice is:
Since you want to run and own a vintage motorcycle grow some balls :D
Take them of and carefully dissassemble and make photos.
Blow out the air and fuel orifices and when the carbs are apart get them ultrasonically cleaned.

EDIT:
Like pidjones said,you need to open up the orifices first.the bath cannot reach spots that are blocked.
 
And you ONLY have 2 carbs! I started with a GL1000 (4 CV carbs) and now I'm working on the carbs for a CB750F (another 4 CVs). Finished #1 today. I'm in no hurry, I'm retired and need to make this project last all winter. I have 2 US tanks. One is big enough to set the entire rack of 4 in, and the power to handle them. But, I've broken them down and doing them individually. There is no substitute for getting the jets out, squirting carb cleaner through each one and running a .008 E string through the ones that are fully plugged with varnish (like the accelerator pump nozzle in #1 today). THEN they go in the US (just to be sure), and body passages are flushed with carb cleaner while the tanks scream. Now, I do have a fall-back if things go bad. Pistol Pete lives about ten miles away from me.

Meanwhile, about 1.5 gallons of Evapo-rust is being rolled from side-to-side int the old tank. Once it is drained and well flushed it will be sprayed inside with MMO, then filled with Stabil-treated 100% gasoline. I'll probably run dual filters for a while. My GL1000 hasn't plugged a filter yet, and it was another horror story like this CB750F.
 
cheese monkey said:
Hi chaps, got two carbs on my Guzzi. It was running reasonably well before I had it and has not run now for about 3 years. Externally the carbs are pretty filthy, internally I dont know. I have fiddled with carbs in the past but I really am not keen on the idea of doing anything again. Do you think it is worth getting them ultrasonically cleaned? There is a place near me that does it for 45quid each carb. I'm thinking they will be sure to run, they will look nice and will give me a good base for any tuning required. On the other hand it might not be necessary and it costs a fair amount of money.

did you drain the fuel from the carbs before letting the motorcycle sit for so long?
gasoline does all kind of things when not drained.
 
You could buy a small Ultrasonic cleaner for less than £90, and do the job yourself. It's very easy to do....https://www.youtube.com/watch?v=oKBdvmGYWQM
EuroCarbs, and Gutsibits stock Dellorto rebuild kits, and any other parts that you're likely to need.
 
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