Valve (engine in general) maintenance ?

[guyom]

Hi Barry thanks. You mean that the values (example 0,004" and 0,008") should be the same for the left and right cylinder. Correct ? Thanks for time !

[nhmaf]

Yes, make the left and right as close as your reasonably can so that when you go to synch the carbs afterwards, you'll *know* that the (2) cylinders are sucking in air/fuel at the same rate, so any imbalance will be in the carb adjustments.

0.004" intake and  0.008" exhaust work fine - I think I run mine at about .005"-.006" intake and 0.008 exhaust.  You don't really want to go more than this or the valves do get a bit extra "clackety-clackety".   Though, as we say in Airhead land - "Happy valves are tappy valves!".  When you cannot hear any valvetrain noise, that is when you have to start to worry and get in there

[georgesgiralt]

Valves are like kids. When there not making any noise, trouble is not far... But too noisy is not good either. Just like kids ;-)

[Barry]

Hi Barry thanks. You mean that the values (example 0,004" and 0,008") should be the same for the left and right cylinder. Correct ? Thanks for time

Yes, use the same clearances both sides but what I was trying to stress was the the setting isn't that critical so for example if you set the inlets at .005" it really doesn't matter as long as both sides are at .005" and more over you use a consistent technique to make sure both sides are as close to exactly the same as you can get them.

[guyom]

Hey Thanks all for reply ! (like the comparaison between kids and valves ;-) got three boys so understand very well this concept ;-))

again a question : when i remove the covers, the right one, low amont of oil inside, but the left one... at least 10-20cc... it is normal or there is something unscrew... i checked the video on valve clearance setup and at some point the guy uses clamps to screw "something do not know the name" and the result was to reduce some movement of the small arms (valve rocker i think)... i do not see any screws at the bottom and top of my R65... how i can check that. i looks like on arm moves up and down a bit more where there is more oil on the cover...

no sure i am super clear...

Thanks for time

[mrclubike]

He is trying to tighten up the side play in the rocker arms by using a "C" clamp to squeeze the shaft supports together 
You want it to be zero play but not tight

It has nothing to do with valve lash but can cause noise
The later rocker assembly's came shimmed from the factory
I just bought some standard stainless steel shims with the proper 16mm ID .05 mm thick and used them on mine to take up the end play of the rockers on the rocker shaft   

BMW sells the complete update kit but it isn't necessary 

[guyom]

HI Guys thanks for feedbacks..

So i checked the clearance and then adjusted the carb. A bit noisy on right side but i will check in 200-300 kms. Just for my information : why valves clearance and rocker adjustment impact on carburation ? if i will understand the order is : Valve clearance --> Carb synchro --> Carb mixture (that's what i did).

thanks

Guillaume

[Barry]

Barry - are you saying that there's some benefit to doing the adjustment slightly warm? Or just that it's not necessary to wait for a complete cool down?

Sorry I'm more than late responding to this.

There is no benefit other than the convenience of fitting it in to a service.  It's just not necessary to wait.

HI Guys thanks for feedbacks..

 why valves clearance and rocker adjustment impact on carburation ?

It's because when you change valve clearances you also make small changes to valve timing. For example if you reduce the clearances the valves are open a little longer and there is more overlap (inlet and exhaust open at the same time). This will require a slightly richer idle mixture than a wider clearance because you reduced the efficiency of the engine at low speeds.

Conversley if you set the idle mixture properly i.e. only as rich as it needs to be, then increase clearances by a couple of thou, it will raise the idle speed and require a slightly weaker mixture.

[Bob_Roller]

There are shims available from BMW, to put on the the rocker arm shaft between the arm and support blocks at each end .

http://www.realoem.com/bmw/enUS/showparts?id=0364-USA-09-1980-248-BMW-R65&diagId=11_1698

Item # 17, available in various thickness .

I've got about 77,000 miles, 125,000 km on the shims and they are just showing signs that they need replacement .