cam timing after cylinder head replcement?

[simonsGSA]

Oil arrived yesterday... With some trepidation I filled up, had a final check and hit the starter... A few moments of cam chain noise then it settled down and sounds really sweet. Only ran it for a minute or so as the oily handmarks on the headers was starting to smoke and I didn't have time to take it out of the garage for a ride. Running in starts this weekend!
Thanks all for your input, is dropping valves common on these, its 33k miles and well looked after so seems odd to me.

 

[Pukmeister]

Are we talking RH cylinder ?.

It isn't "common" but there have been a few (mostly 2005/6) that have snapped exhaust valve heads off the right hand cylinder.

A pal of mine had it happen to his yellow 2005 GS on the way to the dealers on part-ex day. They still honoured his trade-in deal and presumably got the nice chaps at the Fatherland to pay for repairs.

My theory is a choice between overly tight exhaust valve clearances, engines running too lean by design for emissions compliance, and maybe over-revving eg a missed gear change or two. I got my own bike remapped to avoid issues with lean running.

The exhaust valve heads look like they are friction (spun) welded onto thin-walled sodium filled stems, it seems they fail around the weld area at the hollow stem junction, possibly through embrittlement of the heat affected zone.

 

[simonsGSA]

oke

Mine is a 2008, it was the upper exhaust valve on the right hand side that failed. I don’t think the valves were too tight, and I can’t remember the last time I missed a gear on this bike (famous last words????) but I have always thought the plugs look very pale when I change or check them. Maybe it’s a touch too lean and a remap might benefit me. Maybe the leanness coupled with the recent hot weather was the final straw for a pretty lightly made valve.

Either way I rode it today and it seems back to full health.

Your friend was very lucky, it must have been eye wateringly expensive to fix with new parts and BMW labour rates! I used second hand parts apart from rings from Motorworks who have been really helpful. Final shopping list was:

Piston
Piston rings
Cylinder
Head with valves
Cam gear
Head gasket
Base sealant
Base O rings
Oil filter
Oil.

Anyone want some very second hand engine parts? Make nice paper weights?

 

[Pukmeister]

I can't recall the exact air/fuel ratio when mine was done, but I recall the stock fuel map was dangerously lean in places, especially part-throttle which is where we tend to sit for most of the time.

At least with a proper remapping, you can be sure the air/fuel ratio is optimised throughout the rev range in real-world conditions on a rolling road for your engine, not just a generic map made to comply with EU bureacracy.

Best get the running-in period over with first though.

 

[Woland]

AF-Xied at setting 8 doesn't run lean and the engine pulls really well

 

[simonsGSA]

I can't recall the exact air/fuel ratio when mine was done, but I recall the stock fuel map was dangerously lean in places, especially part-throttle which is where we tend to sit for most of the time.

At least with a proper remapping, you can be sure the air/fuel ratio is optimised throughout the rev range in real-world conditions on a rolling road for your engine, not just a generic map made to comply with EU bureacracy.

Best get the running-in period over with first though.

I see you are local to me, who did your remap? Was it done on a rolling road?

 

[Pukmeister]

Hilltop remap on the dyno.

Worth the ride.


Sent from my iPhone using Tapatalk

 

[simonsGSA]

I have heard lots of good things about them on this forum, when I get the chance and a free day I will try and arrange something.