Signs Your Carburettor is Blocked and How to Fix it

How to give a carburettor a basic clean 

The hardest part about carburettor cleaning is getting the bastard off. The rubber seals can be an absolute pain to take off and refit, and if you only have to do a basic clean count yourself lucky, because a deep clean involves taking off the throttle cable and other pieces which can be a complex job. This can be aided by the use of a little head to soften the rubber. Here I’m going to list out the process for taking off and giving the carbs a basic clean step-by-step.

1. Turn off the petrol, you don’t want that leaking while you’re trying to do this, and make sure the bike has been off for a while and cold. Petrol leaking on to a hot exhaust isn’t a good time. It’s also a good idea to drop a few rags on top of the casings below the carb to absorb any fuel that might leak. Set down another small rag beside where you’re working to keep all the bolts and screws that are about to come off the carb.

2. Wear a pair of hearty gloves and some eye protection – carb cleaner is nasty stuff.

3. Remove the rubber clamps, heat up the rubber boot if necessary and work the carbs loose. at this point you can remove the throttle cable if needed or just hang the carb out the side for ease of access.

4. Undo the single bolt at the base of the carb slowly – you’ll probably see a bit of fuel leak out here, and again – make sure your fuel line is turned off.

5. Remove the float bowl by undoing the four Phillips head screws and check it for debris, gunk, rust etc. Give it a good spray with carb cleaner. At this step if there’s any considerable amount of dirt or debris, it may point to a dirty fuel tank and call for the installation of an inline fuel filter

6. Remove the float. This piece is usually held in place by a small pin that can just be pushed out. Take care here while you’re tapping it loose not to damage the mounts. There should be a little valve (the float needle) that the float pushes on to stop fuel flow when it’s at the right level – this should come off with the float. Give this all a good clean.

7. Have a look for the jets under the carb, they look like two bolts with holes in the middle. This is usually where you’ll find a lot of debris and is usually the main blockage culprit. Spray your carb cleaner into the jets and let that soak for a few minutes. if there’s a significant amount of gunk in there you may want to remove the jets carefully one by one and clean off the bike. 

8. Use an air compressor or a can of pressurised air to blow through the jets. Repeat this step until you can see all the build up has cleared.

9. Work your way back up this list to put the carburettor back together. Once reassembled and bolts tightened you can turn your fuel line back on. This should have cleared up what was causing the issue. 

If you’ve finished the basic cleaning steps above, reassembled the carburettor and you’ve noticed a slight improvement in the problems you were having, it might be time for a deep clean. 

It’s worth mentioning here that if you’ve run through all of the steps below and you’re still experiencing sputtering, your issue could be somewhere else – spark plugs, ignition coils, ignition timing etc. If you don’t to go down the deep clean route, most motorcycle mechanics would handle the job.