Thoughts and musings .. tappety noises

APHezzer

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Hello,

So, my r80 G/S has had some rattling tappety noises coming from the right hand cylinder side under load or higher revs since I bought it a few hundred miles ago and I know I need to 'do something'. At mid range speeds/revs and under less load the rattling noise disappears. The rattling tappety noise is definitely rev/load associated as it is 'in time' and increases with revs.

I've checked the valve clearances and they are spot on and the head is 'oiling'. Currently running 20/50 mineral oil which is pretty clean. THe performance does not seem to be affected and it pulls all the way through the range.

Anyone got any ideas on what I should now go looking at .. I did think about checking oil pressure in case in case it is not providing enough oil to the top end.

Cheers
 
Could it be “pinking”?
Maybe a bit of carbon build up on the rh cylinder head.
I only mention this as you say it varies under load etc.
Some engines can suffer from a worn rear cam bearing ,but these are just generally noisy.
Recheck valves and check rocker end float,back off the rocker adjusters and see if the rocker arm needle bearings have wear.
If all seems ok,try retarding the ign a couple of degrees.
If you have a compression gauge do a test,hot.
 
Quick update ...

Valve clearances fine .. checked both sides
Cyclinder head looks okay .. pretty sure it is not pinking but will take a look at ignition timing
Rocker arm float seems okay with just a little bit of 'oil squish' .. so not over or undertight

One thing I did notice was that at some point the pushrods have been replaced and they seem very off centre .. both being in the upper part of the push rod tube and very close to the tube lining .. I don't have a reference but have others experienced very off centre push rods?
 
APHezzer said:
Quick update ...

Valve clearances fine .. checked both sides
Cyclinder head looks okay .. pretty sure it is not pinking but will take a look at ignition timing
Rocker arm float seems okay with just a little bit of 'oil squish' .. so not over or undertight

One thing I did notice was that at some point the pushrods have been replaced and they seem very off centre .. both being in the upper part of the push rod tube and very close to the tube lining .. I don't have a reference but have others experienced very off centre push rods?
Click to expand...
looks like I have answered my musings on push rod position having taken a look at this article: https://bmwmotorcycletech.info/setvalves.htm

.. looks like appearing at the top of the push rod tube and centered is correct .. a useful if detailed read.

Also, I found this video useful, although it is for a 90/6 engine:

Now wondering if I am just being too 'picky' and it's an acceptable level of noise .. I am convinced it is valve/top end related .. going to have a further play with the clearances.
 
They really are just noisy bikes, when tuned correctly. Don't overtighten to get rid of the sound. And there often seems to be one side louder than the other. Usually the right. I've learned not to worry about it.
 
robertotoole said:
They really are just noisy bikes, when tuned correctly. Don't overtighten to get rid of the sound. And there often seems to be one side louder than the other. Usually the right. I've learned not to worry about it.
Click to expand...
Thanks .. I probably need to listen to some other bikes to get a feel for what is 'normal' .. I did actually tighten up a little (.1 inlet and 0.15 exhaust - they were .175 inlet and a little over .2 exhaust) which dampened the noise to my 'personal acceptable' but there is still rattling so I don't think they are over tightened but I may return then and just learn to accept the noise - I'm actually more concernd that the noise=damage/excessive wear rather than being bothered by the sound.

Point about one side being worse than other is helpful .. in my case it is the righthand side as well.

:beerjug:
 
I think you would notice irregular running, and it would be hard to tune the engine to run smoothly (bearing in mind that a GS with 40mm carbs never runs 100% smoothly).

If you check the timing mark using a strobe, and it never settles, jumps around wildly, then that's a sign of timing chain problems.

You can spend a lot of time and money trying to make an airhead GS sound and run perfectly. As the best BMW expert i've known said to me: just use it and enjoy it, and don't be a perfectionist.
 
US bikes usually having the smaller carbs. Do they run smoother? That's what i've heard. The 40mm carbs we have in Europe give a bit more power, but are rougher.
 
Hi (my experience only ….not necessarily facts) obvious but if you use the side stand the oil drains over to the left and out of the rh rocker cover down the push rod tunnel. (Left oil stays where it is.) Try just using the centre stand. Also, although the pillow blocks for the rocker shafts are not adjustable you can buy shims to set the rocker shaft clearance. Also try lightly clamping the rocker shaft assembly before tightening up the assembly. This way you take up any unnecessary play tolerance. Don’t go nuts though since the oil needs to flow. In my experience rocker noise is usually reduced greatly by getting the pots balanced well. Uneven pulses cause all sorts of rattles from engine, cam chain, clutch etc.. If you struggle to balance the engine then you probably have crud in the pilot and main jet assembly. Easy to remove and clean. Avoid crud in carbs by never running the tank low…
Just my thoughts for you. My pd has even sound right and left from doing the above…. ;-)
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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