Exhaust smoke, tapping noise, compression test

The tensioner bolt shouldn't be tight against the tensioner rod if it's the automatic type like other suzuki's I've seen. The only time you screw it in tight is when removing and installing the tensioner. After you install it, you back it out a half turn and secure it with the lock bolt.

I meant the nut that holds the tensioner knob and spring on.

[Tom R]

The tensioner bolt shouldn't be tight against the tensioner rod if it's the automatic type like other suzuki's I've seen. The only time you screw it in tight is when removing and installing the tensioner. After you install it, you back it out a half turn and secure it with the lock bolt.

[2BRacing]

I bought my 850 new in 1981 and it has been making that cam walk noise for many years without getting any louder. Performance is not affected at all and she now has 45 000 km on the clock.

After I learned here on GSR what the noise was, I do not worry about it any more.

I'm in the middle of a top-end refresh and found that my cam chain tensioner was missing the 'lock bolt' which holds the tension knob down against the spring. I believe this means the adjuster was free to slide back. I have a suspicion that was the noise I was hearing, since I hadn't heard any cam walk or anything like it for a few thousand miles beforehand. Only time will tell I guess - hopefully it won't be too long before I get it back on the road.

If I feel like I have extra time, I'll look at the cam walk threads and see if I can identify any movement or worn parts.

[jsandidge]

That is cam walk for sure. Sounds just like mine.

Here's another video - the sound I thought was Cam Walk is back. Is this it? This was about a few blocks ride after starting up after work. I heard this and did some more high-rev riding and this sound stopped, but the other higher pitched, steady sound remains.

https://youtu.be/GZtAZZVCpxs

Is that smoke coming out of the breather tube from the breather cover? Which is on top of the valve cover.

I will take a closer look, thanks for the suggestion.

I'm wondering about the breather tube too. The passage where the breather feeds into the airbox gets clogged with rust, and can cause the crankcase to build positive pressure instead of letting the intake keep it at negative pressure.

That makes sense - the way the smoke comes out from under the tank seems like it's from more of a forced convection (fan or induced pressure) as opposed to natural convection (heat). It also has a bit of an exhaust smell, but I'm sure there's some burning oil residue mixed in there.

Something is making the cam cover oily on the left side. If oil is pooling right on top of the head, it might get hot enough to smoke.

I guess I need to take things apart and clean them up to really diagnose everything. Steve and I had the valve cover off when we did the shim adjustment, but I didn't have much time to get things cleaned up. This bike leaked oil profusely, mostly coming from the tach cable seal (which I refurbished). So the tach cable seal and valve cover gasket are new, the rest is still from the PO (breather cover gasket, head and base gaskets, etc).

If it wasn't riding season I'd happily take the bike apart, replace all the gaskets, clean the valves and replace the seals, get the bolt threads repaired, and probably have the engine cleaned (and maybe painted or Cerakoted). But with these long days "summer hours", there's hardly any time during the week to take on big projects, so it would take forever if I tried to do all that now.

I'll clean what I can, replace the breather cover gasket, try to find the breather hose airbox thingamajig, and see what I can find.

I think that noise is something in addition to the normal valve clatter, but I don't recognise it. Hopefully someone else does.

I guess I agree with you. I was trying to be positive and hope it was nothing unusual, but I know what valve clatter sounds like (I've been driving Nissan Frontiers) and this has a bit more of a metallic ring to it. I don't mind doing some work to diagnose and repair it, I just hope I'm not making it worse by riding.

[Dogma]

I think that noise is something in addition to the normal valve clatter, but I don't recognise it. Hopefully someone else does.

I'm wondering about the breather tube too. The passage where the breather feeds into the airbox gets clogged with rust, and can cause the crankcase to build positive pressure instead of letting the intake keep it at negative pressure. It's not the tube on the airbox where the hose connects, but the rectangular sheet metal box at the very top of the airbox interior. Anyhow, if this is blocked, blow-by smoke might escape a vent hose, since it isn't very tight.

Something is making the cam cover oily on the left side. If oil is pooling right on top of the head, it might get hot enough to smoke.

Is that smoke coming out of the breather tube from the breather cover? Which is on top of the valve cover.

Can you post a video featuring the noise so the experts can hear what's going on?

Here's a video. It's gotten much quieter since the 'Italian Tuneup'. There's a slight tapping which is probably normal valve noise. The phone didn't pick it up very well so I took a couple of videos, and this one I was actually looking more for smoke than sound, but it seemed to pick up the sound the best.

https://youtu.be/JyribgaolnY

[Steve]

Next time you stop by, I'll fire up my wife's bike so you can hear what I KNOW is cam walk, then we can compare that to your noise.

.

Sure, I'll do that next chance I get.

I've been doing a little research and am starting to lean toward 'cam walk' as my hypothesis, or at least something related to cam walk. The 'synchronous' sound I heard when I was stopped at a light, and another peculiar noise I started hearing/noticing which I thought sounded like cards in bicycle spokes (but faster and quieter), so maybe the cam chain tensioner needs an adjustment and is allowing cam walk. This all makes me feel a little better - I can live with it as long as I know it's not causing harm (or can be fixed with a cam chain tensioner adjustment).

I'll do the RPM check and see if it goes away at 1200-1500 rpm...and take a video.

[Dogma]

Can you post a video featuring the noise so the experts can hear what's going on?

I tightened the loose exhaust clamp, torqued the engine mounting bolts (had some handlebar vibration), put things together and went for an 'Italian Tuneup' ride. At one point I was at a stop light and the tapping was really loud, to the point where I could basically feel it, and it was sort of cyclic (rapid taps, constant rate, but amplitude varying sinusoidally). I kept up the ride and it seemed to quiet down to where it was before. When I got home, the tapping sound was constant: if I listen near the left side valves, I hear what sounds like normal valve noise. If I listen on the right side, it's a similar kind of noise but much louder - like the valve is hitting as opposed to sealing. It could be a number of things so I don't want to say it actually is some kind of valve interference yet. The first 2 things that I did with this bike was bring the carbs to Steve and have him help me with valve clearance, so it could be something else (cam chain adjustment? although the adjuster was refurbished...)

I didn't get a good look at the exhaust smoke - it needs to be dark with a headlight behind me, and it was late so I didn't take the time to get out my maglite when I got home. It also wasn't a very long ride so I figured it needed more time before reassessing. I will say that this bike is a freakin' animal - at 6,000+ rpm in 2nd and 3rd I had to hold on pretty tight But it was very stable and no sign of vibration until 7000-7500 rpm (I cut back throttle as soon as I felt it, so I don't know what the exact number was).

[Dogma]

It looks not like work is going to run late tonight. We'll see if I can get out.

It seems ridiculous to me that we had to go to Indiana to finally meet.