Low power, right side engine rattle.


Information and questions on GL1100 Goldwings (1980-1983)
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nickgroves0308
Posts: 17
Joined: Wed Apr 14, 2010 8:47 pm
Location: Oak Lawn, IL
Motorcycle: 1982 Honda GL1100 Gold Wing

Low power, right side engine rattle.

Postby nickgroves0308 » Wed Jun 09, 2010 11:07 pm



So, I've posted this topic before but I wanted to add some details.

Hears the problem:

Bike has a rattle and vibration, while riding. Rattle is coming from the right side (cylinders 1&3). Upon acceleration rpm 2k - 4.5k there is power loss/lag and that dang rattle that sounds like it's coming from inside the engine. Like I said it's the right side that the sound is coming from. The funny thing is that when the bike is in neutral and I rev the engine, there is no rattle whatsoever. Everything sound good until you put the bike under load while riding. Wingadmin told me that it might be a carb synch issue and that it could be the cam chain rattling around due to unequal cylinder power. However, why would I only hear the rattling on the right side, if that is in fact what's going on? The bike idles fine and come off the line ok but as soon as you hit 2k on up, it rattles, acceleration is poor, and there is some pretty heavy vibration. She moves pretty good as soon as you hit the higher rpms but it still feels rough.


What's been done:

Carbs rebuilt, not synched but close enough, I think. New Plugs all around. New spark plug caps/boots ( 2&4 only). Caps on 1&3 seem to look great inside. New air filter, fuel filter, and fresh gas from clean tank.

My major concern is that the rattle is in fact a valve, piston, or rod moving about and damaging my engine. I'm not sure but could the problem be a timing issue or could it be a spark/fuel issue?

Thanks a lot guys. This forum is extremely helpful and I am so appreciative of all the information provided.

Nick



jimac
Posts: 12
Joined: Wed Aug 19, 2009 2:30 pm
Location: Newcastle, England
Motorcycle: 1983 GL1100A Aspencade

Re: Low power, right side engine rattle.

Postby jimac » Thu Jun 10, 2010 9:12 am

Well, first off it can't be a cam chain rattling as there isn't one! The Goldwing uses belts to drive the camshafts and they don't rattle. I suppose it could be the primary chain (which transmits drive from the crankshaft to the transmission) and they are known to rattle a bit but I guess the real problem is what is making it rattle. This has to be something that is causing uneven running and therefore the engine to be out of balance.

Carbs are the obvious culprit but you say they have been rebuilt. I know a lot of emphasis is often placed on synching the carbs but they would have to be a long way out of synch to cause noticeable uneven running under acceleration and you would notice an uneven, lumpy tickover. Could be an air leak, or a failing accelerator pump diaphragm.

Failing coils can give uneven running, but normally this would be at higher revs rather than lower and clearing as the revs get higher.

Don't get too hung up on the right-hand cylinders failing just because that is where you hear the rattle. The rattle is more likely a symptom than a cause, and broken valves, pistons or rods would be noticeable at idle and you wouldn't want to take the revs very high due to the "rattle" getting worse.

I think you may have to revist the carbs, and it might be worthwhile changing the plug caps on 1&3 as a visual check doesn't always prove anything!

nickgroves0308
Posts: 17
Joined: Wed Apr 14, 2010 8:47 pm
Location: Oak Lawn, IL
Motorcycle: 1982 Honda GL1100 Gold Wing

Re: Low power, right side engine rattle.

Postby nickgroves0308 » Thu Jun 10, 2010 10:05 am

Thanks for the speedy reply jimac. I'll take another look at the carbs and change out the spark plug boots. I appreciate the info.

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WingAdmin
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Re: Low power, right side engine rattle.

Postby WingAdmin » Thu Jun 10, 2010 2:23 pm

It's the primary chain rattling, and 1100's are famous for it.

Any time you have an imbalance between the power being developed by the individual cylinders, you will be putting uneven power pulses into the crank, and at certain RPM's (mostly lower RPM's, and the more throttle you're giving it, the worse the noise), this will cause the primary chain to resonate and make a hell of a racket. The solution is to balance the power output of the cylinders as best you can. The good news is that you'll end up with a much smoother-running engine as a result, with a lot less vibration.

Check the compression of the cylinders, if you haven't already. If you have a fair disparity in compression between one or more cylinders, you've found your culprit right there.

Assuming the compressions are all fairly close, you can adjust your valve clearances, clean and gap your plugs, and when you're all done, the last thing you should do is synchronize your carburetors. That will give you a nice, smooth-running engine, and the rattling noise will diminish significantly - it will never go away completely, but the RPM at which it happens will be lower, and the power setting will have to be much higher.

nickgroves0308
Posts: 17
Joined: Wed Apr 14, 2010 8:47 pm
Location: Oak Lawn, IL
Motorcycle: 1982 Honda GL1100 Gold Wing

Re: Low power, right side engine rattle.

Postby nickgroves0308 » Fri Jun 11, 2010 9:47 am

Thanks wingadmin. Sorry I was mistaken as to what chain was making the noise. So the "primary" chain is the likely cause of the rattle. I will do as you suggested and check the valve clearences, compression, and plugs. Thanks again.




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