does anyone have any ideas as to my engine idle problem.......when i start the bike up the engine sounds fine ticking over at about 1200-1500 revs, but it will suddenly drop revs and a knocky sound can be heard from the engine, the engine will immediatly return back to idle and sound fine again, when i rev the engine no sign of the knocky sound can be heard.
i cant seem to determine if its head or base of the engine the sound is coming from, the engine sounds fine apart from the slight knocky sound , this happens now and again and its not constanly there, the engine pulls well sounds fine and goes well, also there seems to be slight back pressure into the carbs, as ive noticed a sort of backfire although its not from the exhaust its from the head into the carbs, ive changed the plugs for new standard ones and :dunno_white:regapped them, and ive cleaned the air filter.... ?
i was told its the cam shafts moving side to side causing the knocky sound... and that its normal.... but i dont think the knocky sound is normal is it ?
the plugs seem to indicate the engine is running fine ive checked the pilot screws and im about to ballance the carbs. but i dont really want to have to take the engine apart . does anyone have any ideas as to what it my be.......i hope its not the main shaft shells or crank shaft....... the bikes a gs 500 e 0n a 2003 plate done 12,000 miles
The GS does have a knocking noise, which according to Suzuki is not a problem, but they do have a fix.
Suzuki released a bulletin on 3/21/06 regarding this matter. I have yet to find out from the dealer if this is a free fix.
And Welcome!!
Welcome gw0wvl, you describe it slightly differently here than on the other forum but it still sounds like the harmless camshaft knock to me. I've only experienced it at slow idle with a hot engine; never heard the camshaft knock with a cold engine when the oil is thicker.
Sooner or later you need to check your valve clearances so you might want to check your camshaft endplay when you have the valve cover off, I did when I first had the knock on the 97 GS and found considerably more endplay on one camshaft than the other. Never bothered to check it on the 02 GS but have heard the same knock on occasion.
If you click on search above and search for camshaft knock or engine knock you will find much discussion of this problem has taken place here. Others will probably jump in to express opinions and ask questions regarding your knock problem.
Welcome!
Since you experience a drop in RPMs as well I rather think it's something to do with combustion. Might be an upstream backfire. Which might be related to valve clearance issues. But then, it might just be choppy ignition at idle, causing the chain to knock.