Valve Clearance adjustment
 

I just had the BMW dealer in Lima check the valve clearance on my F650GS twin and, as I suspected, it is out. The engine pulls fine but sounds a little raspy. They didn't have the shims to adjust it though. My question is, how urgently do I need to sort this out and can anyone suggest a place preferably in Lima, or possibly Bolivia, my next destination, that could deal with this?

Thanks!

This should be a no brain er for any competent mechanic.
The shims for your bike can be sanded to the correct thickness
on some emery paper, if the correct sizes are not at hand.

I'm not sure what diameter shims your bike needs.
Find out the dimension and call other shops.

I'd try the KTM shop in Lima, there's also some good dirt bike
shops in town.

Get it done in Lima.

Did the mechanic who checked your valves determine what shims were
required ?
That would be good info to have while calling around.

Max

Thanks for that. I will try to find the KTM dealer. I have been searching to no avail to find the diameter of the shims in my twin. Lots of info for the singles but always hard to track this sort of thing down for twins... What I did find is that the shims are 'semi-spheres' and that the intake and exhaust valves are different sizes although I imagine this does not necessarily mean the same for the shim/semi-sphere sizes??

Another thing I read in my travels is that on this bike the clearances tend to get smaller with engine wear so it's likely that I could just sand down the existing shims?? The dealer who did the clearance measurement seemed so slack about the whole thing I'm not sure I would trust his figures...

Ask for the shim spec's on advrider.com.

I'm a KTM guy so I'm not familiar with the beemer shims.

As your valves seat into the valve seats (head) the distance between the valve stem and the shim, bucket, cam decreases.
So generally, unless something is out of wack, the new shims will
be thinner.

The problem with tight tolerances is that the valves can remain slightly open at TDC causing burnt valves, in the worst case.

Twist it, Max

After searching around the web a bit it looks like you motor has a
shim shaped like a mushroom top, which will be specific to BMW's
and not available at any other moto shop.

It still seams like the flat side could be sanded down a few thou.
I do that on my dirt bikes all the time.
There is no issue with grinding through a hard surface coating.

Looks like your options are limited.

Max

Thanks Max. I just went back to the BMW dealer and they are telling me that I need bigger, not smaller shims. The mechanic has made this diagnosis by listening to the raspy sound of the engine and by 'scanning' it - using the onboard diagnostics. I am getting them to open the valve cover tomorrow and check the clearances exactly with a feeler gauge.

Then my problem will be waiting for shims to arrive from Europe... Luckily I am planning to return to Lima in a couple of weeks after visiting the north coast. But I am hoping to find a quicker (more expensive no doubt) way to courier the parts from Europe. FedEx?? Any suggestions??