Hitchcocks Forum

HI
Anyone know a really effective carb cleaner especially non proprietary that will get all the metal clean and any foreign bodies melted away?
I need to be sure all the little passages in my Mikuni are free of blockages. It is the, now, main suspect for making the engine stop after a short (float chamber emptying) run. Any suggestions please?

It might seem a bit odd, but I've always found the best carb cleaner to be petrol. I use a small clean paint brush, and a clean old soup dish and simply carefully wash all the components in the petrol. Then place to dry on some clean newspaper. You can then blow through the jets once they are fully dry. Obviously it goes without saying that you've got to take care to keep the garage ventilated and don't work near a roaring fire! Oh, and don't put the petrol back in the tank when you've finished......

Graham I had a Monobloc that needed a thorough clean inside& out. I used a company in Birmingham (but they're everywhere) to clean the carb ultrasonically, cost was reasonable @ £20 and it's now like new, if it's within your budget I recommend this technique, regards Brian

I`m confused here,how can you have little passages/ blockages to be free when there`s no fuel in the float chamber? There`s only one way to clean a carb and that`s a strip down.What`s a non proprietary cleaner?

Graham, for £20 or so you can buy an ultrasonic cleaner. I got mine from Aldi, but Maplins sell them. I use neat Cillit Bang for cleanig carbs.

Hi guys--------- GRAHAM43, as WESTYBOY indicated the ULTRASONIC method is by far the best (IMHO, that is)..........have a look at this }----------- http://www.youtube.com/watch?v=xhGyK6MpkOQ ---------------- I have used this particular firm in the past and can reccomend them. You may want to do as I did and buy your own unit, there are LOTS for sale on E-bay, like this one for example }-------http://www.ebay.co.uk/itm/0-44G-2-0L-50 ... 5593?pt=LH --------------- OR, why not get a group of you to club-together and buy one of the larger commercial units. The system uses microscopic bubbles that collapse and the resulting pulse of energy mechanically scrubs the metal etc.... It's ideal for pilot fuel jets and the like. I regularly use mine and has been well worth the initial outlay.

I would have thought that the float chamber emptying has to be a direct reslt of no fuel getting into the chamber and the only passageway this fuel comes through is the fuel line and the needle and seat. I would be suspicious of an airlock forming in the fuel hose

Hi Graham. I strip out all the jets etc. then I use Isopropyl Alcohol (Propanol) for cleaning out the gungy deposits inside the body float chamber and the jets. Acetone can also be used too for this purpose. Then I clean the entire body inside and outside with phosphoric Acid to leave the carb looking brand new. Don't leave the acid on the slide and slide barrel too long though. If there is some external corrosion I sometimes use wire wool or wet and dry before using the acid....Then I use very hot soapy water to swill everything out and finish with the Alcohol to dry the whole thing off and then blow through all the small air and fuel drillings. I refit the jets after checking by eye that they are all clear.....If it's an Amal Monobloc carb, I then use a rotary polishing mop on the casting to get the carb shining like chrome...the shine lasts for quite a time surprisingly.

As Les said, phosphoric acid cleans alloy up a treat but don't leave it too long!!! A useful source of phosphoric acid is rubarb; just boil some up and stick the carb in for a few minutes. Just make sure you get all the bits out afterwards

--------- whichever method you choose DO make sure that you have a supply of compressed air available. If you are cleaning a Mk1 Concentric then take a look at the route the primary air travels in the main body. You'll see that there is a 90 degree bend in it which can be difficult to clean 100%. We had one recently where the pressed-in jet bush had created a piece of swarf which partially blocked the passageway--- been like it from new !! Having cleaned your carb, you then need to "prove" all passageways to be clear.