Strange Noise

[Dave M]

Been messing with Carbs and attempting to tune the Stag, tried a pair of recon carbs with no success, no better than my own Stroms and peed out fuel but that's another story. Before I removed the Stroms I sprayed carb cleaner around the inlet manifold area to check for air leaks. No difference in engine note but I did hear a noise that sounded like a valve closing, a metal to metal thunk is the best way I can describe it.
As I had bought Johns (Koy 23s) Weber I decided to fit that. All fitted but when I spray the carb cleaner around the Inlet manifold area I still get the thunk noise. Any ideas what this noise may be?
Have to say first impressions of the Weber seem good, tick over is far smoother but I've not been out for a run yet. Just concerned about the noise mentioned above.

[Staggard]

I don't know the answer just bumping you up the list. but has the carb cleaner got ether in it ( like easy start I think it was called ) we used to start deisel's with it. That used to cause a sort of a pre ignition knock that sounded metallic. Graham

[Dave M]

Thanks Graham
Could be pre ignition but if it is how's it entering the system when I spray it around the inlet manifold?
If its an air leak on the inlet manifold it must be a large one as it doesn't seem to matter where I spray the stuff it still thunks. I've retightened all the inlet manifold bolts so at a bit of a loos now, don't want to remove the inlet manifold and replace the gaskets if its something else causing the issue.
Dave

[Staggard]

So if we look at this logically, it's possible that there was an air leak before hence problems tuning the strombergs, we can assume there is no mechanical problem because there are no noises unless you spray the cleaner around. Does it show any sighns of running weak plug colour, pinking,flat spot's ect, is there any way you can get it on a colourtune or a Co meter/alanizer. I am thinking on Graham