'80 GS1100 Engine Noise

[Guest]

I have been fixing up a 1980 GS1100 for the past few months. At this point I have all the electrical sorted out and I have her running, but the engine does not sound good. Even at idle, something sounds off, and when I increase the RPM there is a definite rattling sound. I made a recording, here is the link:

Engine Sounds

The first 15 seconds or so I recorded from the right side of the bike near the engine, then I gave it some throttle. The next part is from behind the bike near the exhaust. Finally I recorded from the left side near the engine because I thought I could hear the rattling better from there.

I have a feeling that multiple problems exist here. From searching around on forums, it seems as though the rattle could be from the chain tensioner. Even without the rattle though, the engine doesn't sound too healthy. Any help/advice would be much appreciated, thank you!

[azr]

Have the valves been adjusted and synched already? have you rebuilt the cam chain tensioner?

[grantcrose]

no to both questions. Although the bike is an '80, it only has 6k miles on it (it sat in a garage for 20+ years). I have the clymer manual, from reading through the basic tune ups I didn't think that was something that I needed to do. I did clean out the carbs, change oil + filters, replace spark plugs, etc. though.

[grantcrose]

is there a simple test to see if these things need to be done? Or, considering the bike's age, is it safe to assume that they definitely do?

[azr]

oohhhhh....well if you're sure that it's 6'000 and not 106'000 why don't you just ride it for a bit and see what happens? the noise didn't sound like something was going to blow up. If the bikes' been sitting it needs to be ridden then have a look/listen to it. Put a gas tank or two through it and then have a look. Remember though, you have no idea what was done or not done to the bike, maybe the valves have never been adjusted?? just saying. The 'simple test' is riding the bike, but if you don't the GSes you won't know what to look for. Basically valve adjustment is routine maintenance and there's no sense in leaving it because you have to do it like you do brakes. But run the bike a bit first. Once you've ridden it a bit it'll show you what else needs doing. How are you compression numbers? if you cleaned your carbs properly that means you need to do a vacuum synch anyways to get them running well and since you need to do that you might as well do the valve adjustment before that as each time you do a valve job you have to resynch.

[grantcrose]

I have probably put ~200 miles on it since I redid the electrics and got it running. (I wanted to test her out so I took a quick trip down the coast). Only recently, in the last few weeks, did I notice the sound.

I can read through the clymer manual and get the valves adjusted. Do you know how the cam chain tensioner can be inspected? I don't see anything on it in the manual.

[azr]

aahh..To determine if the cam tensioner is working properly, while the engine is running at an idle grab the knob and turn if ever so gently to the left, you should start to hear a clacking noise in the engine as the chain loosens, then let it go and it should go back to proper tension and the noise disappears. Remember, gently is the word. If you haven't done the valves just do them and then synch the carbs. While you're in there check the torque's on the cam cover bolts (careful to to snap any) and check you chain is fine (should be due to the low mileage). If you're concerned about the tensioner they're pretty easy to rebuild.

[grantcrose]

Thank you for all the advice, sounds like my weekend is set