Kawasaki GT 550 Tapping noise ?

Robby · Dirty Old Man Joined: 16 May 2002 Karma :

I would be wary of trying to diagnose too much from noises in the video. It does sound nasty in the video, but it's an aircooled bike, in a garage, with the sound caught by a phone. I don't know if it sounds like that in real life, or if the phone is amplifying the engine noises.

As a general rule of thumb for Jay, the engine should not be noisier than the exhaust.

The fact it is running means you haven't done something like put the cams in 180 degrees out, or have the camchain in totally the wrong place. It wouldn't be running it if was out by more than a tooth.

If it is clutch basket rattle, that normally goes away when the carbs are balanced.

So, yet again, rule out the basics first. Carbs all set the same, according the manual, and balanced. Carb balancing port covers all in place. Exhaust gaskets good. Valve clearance set properly.

Jay2903 · Scooby Slapper Joined: 03 May 2016 Karma :

bikenut · World Chat Champion Joined: 21 Nov 2011 Karma :

to prevent hair loss, take the carbs off and check the rubber stubs and fitting faces.

Bench test float levels and fuel hieghts.

You will need a fuel tank of some sorts say 1 litre capacity and some clear tubing.

Make a bracket using the carbs bottom large screws that screw the cross bar to the carbs. This bracket will allow the carbs to be vice mounted ( via the bracket ) as a third hand keeping the carbs level etc.

Once plumbed in the carbs drain stubs can be used to "see" fuel level in each carb float bowl by arranging the clear pipes to stick up above the tops of the carbs, and with the drain screws slightly open, the level of fuel in each carb fl;aot bowl can be seen and compared with reference to each other and the carb float bowl to carb body gasket line, sound complex but its simple. There is a fuel level quoted in the manual that i will look up for you, for the 750 model.

bench throttle butterfly balancing. Using the bracket again, with the carbs angled back somewhat ( so the ball bearinsg used rests against the closed butterflyies ) .

Arrange so that each dash pot piston ( thats the piston attached to the rubber diaphragm ) is raised and place a ball bearing down each venturi so that the ball rests against the closed butterflies.

Open the bitterflies via the cable cam slowly and look/listen to the balls falling thru past the opening butterfly, did they all drop thru at the same time??

If not ( probably the case if the carbs where seperated/worn/fiddled with ) then adjust so that they do.

Look at the adjustment system. From memory the left air are balanced to each other, then the right pair to each other, then the pairs to each other. Look between the carbs and see the joining system and the adjusting screws and lock nuts.

Again this sounds complex but isnt, just time consuming and fiddly.

When done, refit carbs to engine, prime and start engine, smoother now??

For final fine tuning then use the vaccum gauges remembering you get what you pay for.

You could make your own manometers, aquarium bits and bobs are useful.

Bench test and set first else expect hair loss and remember fire risks.

I suspect the engine may have to come apart again. With plugs out and turning engine over by hand in the correct direction of rotation, any tight spots/clicks etc..????
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Riejufixing · World Chat Champion Joined: 24 Jun 2018 Karma :

Jay2903 · Scooby Slapper Joined: 03 May 2016 Karma :

Jay2903 · Scooby Slapper Joined: 03 May 2016 Karma :

So I’ve set the carbs up on the bench...
I ran it for a couple minutes, it’s not firing on all cylinders Despite having fuel and spark all round.
Here’s that sound again nonetheless.

bikenut · World Chat Champion Joined: 21 Nov 2011 Karma :

mmmmm 2 noises, the thumping tapping one and another that sounds as if it may be the starter motor trying to turn/energised???
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bikenut · World Chat Champion Joined: 21 Nov 2011 Karma :

so carbs floats set and fuel levels compared and adjusted, fiddly yes but good practice for even running.

Carb butterflies set so all the balls drop thru past the butterflies at the same time, again fiddly but needed for good smooth running. The above should be done ON THE BENCH!!!

Fine tuning with vacuum gauges when carbs on bike and engine running, fine tuning. Again fiddly but if bench settings done that is a good starting point, saves much hair loss!!

I assume all the carb to head stubs are good with no cracking or air leaks etc., and the carb butterfly spindles are not toooooo worn, else air leaks there as well.

What did you set the valve working clearances to, mid point more or less between upper and lower limit?

Cam chain droop set and the the correct cam shaft in the exhaust position etc..

Does yours have a cable driven tacho or electronic?

You got some of those red neon plug caps you have been told off some time ago? they will come in real handy now........

cam chain tensioner is the cross wedge one? 2 wedges and spring type??

A timing strobe light is also a good bit of kit, how is ign timing?

You took the head off and barrel to do the piston rings ( if you didnt you are far more clever than i, or anyone else on here for that matter!! ) and you DID fit the cam chain tensioning blades correclty????
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