GL1100 Engine Rattle Noise?

[Goldenroad12]

Hello All, I just recently purchased a 1983 Gl1100 Standard that has previously sat for the last 6 or 7 years. I have been going though the bike and replaced all the necessities like timing belts, full carb tear down and rebuild, oil change, etc. I had just gotten the bike together and fired it up for the first time the other day and it runs super smooth at idle and it has a really crisp throttle response. I noticed it has a rattle like loose hardware on the bike when reving up and returning to idle but it seems like its above 2500 rpm. below all the its very quiet and smooth. I took it for a ride and under a load the bike makes no noise until high rpm again and on decel. If you lug it in a high gear it doesn't do it. I don't think it is rod bearings or anything terminal but i am also clueless on what it could be. The bike has 43k on it and i have yet to sync the carbs. I did a gl1500 hot coil conversion and eliminated the ballast resistor as well. At idle it sometimes coughs back through the intake on the #2 cylinder. The timing marks were on before and after belt change. The vacuum advance unit works just fine. I don't understand what i'm missing unless my belts are too tight and the carb sync will fix it? Thanks for any thoughts or comments fellas! other than this issue I love the bike its great.

[DaveO430]

Could be in the exhaust. The headers have a double walled pipe, I had one once that the inner pipe had broken loose.

[Goldenroad12]

Yeah I never questioned the exhaust before. I had a 79 Yamaha XS1100 that had that problem before and I had to cut it apart and fix it. It Could be the exhaust. Would un-sync carbs cause a rattle or clattery noise? I don't know if something is tight in the engine because it had gas and oil mix in the crankcase and it sat on the side stand. I think the intake valve sometimes sticks on the #2 cylinder that's why it sometime coughs through the intake. Maybe the valves are out of adjustment? I haven't had the valve covers off yet or the sync gauges on it.

[DaveO430]

The synch basically only affects it at idle and a little bit after. Probably lean on #2. Adjust the valves before synching the carbs.

[Goldenroad12]

Carbs are now set perfectly, valve lash is set, and timing belt tension was revisited. It still vibrates/rattles but its more of a "tinny" type of a rattle that could be the fairings or exhaust I suppose. Its just the nature of the beast I think.