Carb sync/rattle while accelerating from idle

[Ruffian]

Hello Everyone,
New member here! I am about to make one of my childhood dreams come true by getting one ´79 GL1000.
It seems to be in good condition but it has some issues: it has been sitting down for a while so the carbs will need some cleaning/adjustment.

My concern is a rattle / knocking sound when suddenly accelerating the engine. According to the owner, this is because of the carbs being clogged/out of sync making one cylinder fail to ignite properly. And that the bike was running perfectly before being put to rest. This disappears once the RPM are somehow stabilised.

Is this something reasonable? could it be the timing chain being shaken by the misfire? I have a short video but I need to figure out how to upload it.

Thank you!
Cheers
Roy the Ruffian

[WingAdmin]

The rattle is actually the primary chain (a hyvochain) inside the engine that connects the output of the engine to the input of the transmission. If the cylinders are not balanced correctly, then at a given throttle setting, some cylinders will be putting out more power than others. This sets up a vibration that rattles the hyvochain and makes that awful noise.

Balancing the carbs will go a long way towards fixing this, but even with perfectly balanced carbs, if you lug the engine at low RPM, the chain will still rattle. So don't do that (it's not good for the engine anyway).