Valve Adjustment and Motor Oil question

[badgertom]

I want to adjust the valves on my '82 R65. The R65 Rider's Manual indicates a 0.05 mm gap for the intake, whereas
both Clymers and Haynes Manuals state the gap should be
0.10 mm. Since I have some "noise" in one of the cylinder typical of a valve problem I would like to know which gap to use. Also, when I rotate the tire to get to line up the the TDC with the index mark on the case the wheel just pops ahead making me pass the point. Is there a trick to getting this without many tries?
My second question has to do with an oil change. I currently use synthetic Amsoil 20W-50 for motorcycles. My dealer no longer carries the brand nor can I find it in any stores near where I live. So, can I change to some other brand of synthetic oil 15W-50 without causing any harm to the engine? The dealer tells me to keep with the Amsoil. But, if I can't readily get it I have to change. Any thoughts? Thanks for any help.

[Barry]

All your sources were correct at some point in time.  Valve clearances were changed several times by BMW and eventually settles at 0.1mm (0.004")  inlet  and 0.2mm (0.008") Ex.  To be honest they are really not that critical but strive to make them the same for both cylinders.

Unless they are very much wider than those specs i.e in excess of 0.25mm ( 0.010") the clearance itself isn't the reason for excessive noise. It's more likely you have too much end float on the rocker arms.

Just my personal opinion and I know others will not agree but the method of setting the engine at TDC by rotating the rear wheel in gear borders on barbaric and all but impossible to do accurately if for example setting static ignition timing.  I use an Allen key in the alternator rotor bolt with the spark plugs out. There are other methods of setting the engine position for valve clearance checks but TDC is the official method and the simplest.

You can change to another brand of synthetic oil with no problems at all.

[Tony Smith]

Just my personal opinion and I know others will not agree but the method of setting the engine at TDC by rotating the rear wheel in gear borders on barbaric and all but impossible to do accurately if for example setting static ignition timing.  I use an Allen key in the alternator rotor bolt with the spark plugs out. There are other methods of setting the engine position for valve clearance checks but TDC is the official method and the simplest.

For what it is worth I totally agree with you Barry.
On the other hand we mildly disagree on the topic of oils.

I fail to see any advantage whatsoever in running synthetic oil in our bikes, I do see a lot of potential problems, starting with leaks and ending with he fact that few (if any) synthetic oils have an additive package designed for air-cooled engines.
 
My own view is that a specialist mineral oil with additive package tailored for air-cooled engines is the way to go - principally the inclusion of high amounts of zinc.

In Australia we are lucky to have a premium blender by the name of Penrite who makes (amongst many others) a 20W60 blend specifically for air-cooled engines. I have used Penrite in my BMWs since the early 80s and I have never experienced a lubrication failure.
 
I say the above from the standpoint of owning a 1978 R100RS  which some here will know as being a model  (in)famous for destroying both its oil and the engine due to the small capacity sump and the high temps caused by both the output of the engine (the 78 has I think the most horsepower of any airhead) combined with the effects of the fairing.

I have run Penrite pretty much since new and have never felt the need to retrofit an oil cooler - in the 1980s I used to send samples of changed out oil away for analysis and the reports always indicated that the oil was still doing its job.

I will admit to having recently bought a period aftermarket deep sump for it from Larry Chibara - purely to increase the oil volume.

[badgertom]

Thanks, I will give that a try. The wheel rotation drove me crazy. The 0.10 mm on the intake ( and 0.20) on exhaust
seems good enough for me.

[badgertom]

If there is too much float on the rocker arm what can I do? Do I have to replace the rocker arm. I check if there is excessive movement but all seem tight. Rocker Arms are not cheap. 

[mrclubike]

The rockers can easily be shimmed and no need to buy the factory upgraded rockers that they sell with the shims
Just put them on the bottom

I got these from McMaster-Carr

You do not say what part of the world you live in so  I don't know if you can get these   from Mcmaster

I use 20w50 V twin Mobile One because I feel it will do better in the cold

[mrclubike]

Allen wrench in the rotor is the way to go

I drilled a hole thru the front cover and plug it with a timing hole plug

[Tony Smith]

Allen wrench in the rotor is the way to go

I drilled a hole thru the front cover and plug it with a timing hole plug

That was clever thinking - I take my hat off to you.

[wilcom]

Allen wrench in the rotor is the way to go

I drilled a hole thru the front cover and plug it with a timing hole plug

That was clever thinking - I take my hat off to you.

+1 on what Tony said......

That was thinking outside the cover!

[Justin B.]

Slick!  I may have to try that...

[BPT]

I was thinking the same thing.......

[Barry]

On the other hand we mildly disagree on the topic of oils.

In your climate I also would probably not bother with synthetic provided the mineral could cope with high oil temperatures.  I don't use synthetic because it has some magic ability to lubricate better than mineral, I  don't believe it does.  The major benefit for me with synthetic is the way it flows for cold starts during the winter.  I use 5W40 which is not available as a mineral or if it is it will be so full of viscosity index improver there will be little room left for the oil.  Synthetic, whether real or pseudo, inherently has a higher viscosity index so needs less additive leaving more oil to lubricate.

Although I've never experienced it I do believe synthetic has the potential to cause leaks most likely through it's higher levels of detergent but if the OP has been using synthetic for some time a switch to a different brand is very unlikely to cause problems.

[mrclubike]

I haven't had any problems with oil leaks  caused by using Mobile 1  V twin
The oil gallery plugs are the only oil leaksfrom the engine that I have had
Final drive is another story
And I use dino only in it

[mrclubike]

The rockers can easily be shimmed and no need to buy the factory upgraded rockers that they sell with the shims
Just put them on the bottom

I got these from McMaster-Carr

You do not say what part of the world you live in so  I don't know if you can get these   from Mcmaster

I use 20w50 V twin Mobile One because I feel it will do better in the cold

You may want to get a pack of .004 thick shims with the .002

When reinstalling my rebuilt heads today I had to reshim
the rocker end play and I   had to use some .004 thick shims plus the .002's
 

[Adrian]

In Australia we are lucky to have a premium blender by the name of Penrite who makes (amongst many others) a 20W60 blend specifically for air-cooled engines

Thanks for this Tony - having got my rebuilt engine back I've been wondering who's oil to use - as we both live in Oz this is timely advice :-)
.
And Mrclubike - great modification for the allen key - I shall do the same -
.
I think this site is great - I pick up all sorts of very usueful tips and tricks _ thanks guys