Engine noise at 3500 rpm no load

[crguy]

Hello, my 1983 r65 began to emanate at ting ting noise like you would hear when tapping your fingernail on a coffee can from the left front timing chest area, noise only happens when at 3500 rpm an above while cruising with no load, but if I accelerate or back off throttle the noise ceases immediately, I can't even replicate when on center stand, I opened chest to expose chain which only has 4 years and 22000 miles since last change out thinking I'd find a busted tension er or some physical evidence but all is clean, the hydraulic tension er is extended more than I think it should be so I'm going to change chain again but I'm wondering if this sound which is a ting ting sound when cruising along 3500 and greater is something someone is familiar with,,,thanks for listening.
      

[montmil]

A complete timing chain and guides replacement should also include the coil spring that applies tension to the chain tensioner piston. IIRC, there is no oil pressure involved behind the piston.

When I did a chain chain replacement on my '81 R65, I used the full kit from Motobins which included a new coil spring. My original spring had evidently lost its tension as it was considerably shorter than the new spring. YMMV

[crguy]

Yes I agree and I did a complete job only 22K miles ago including new sprockets all after going 125K on the original that was still quiet with a solid timing mark but I changed it anyways due to age, just seems too early, maybe it's a bogus chain, can't remember the amount of tension that a chain should have and just wondering if the 3500 rpm noise indicates it could be something else.

[Bob_Roller]

Have you done anything else to the engine ?

[Tony Smith]

IIRC, there is no oil pressure involved behind the piston.

My understanding is that all R65s and all airheads after 1979 have a hydraulic tensioner. Please see the photos at http://bmwmotorcycletech.info/timingchain.htm

I do agree with you that replacement of the complete kit of parts is a good and sensible idea, delving into the timing chest of an airhead is not rocket science, but there is no reason to have to do it more than once in a blue moon.
 
OTOH, my R100 (and I suspect yours) have purely mechanically tensioned duplex chains which in spite of BMW's protestations to the contrary, continue to last near on forever whereas simplex timing chains wear out with regularity.

[crguy]

Yes Rob, when I changed chain last time I also installed dual plug heads, since I've added an Alpha bean can....I just checked my parts invoices and it was only Feb of 2012 when I performed chain, tensioners, sprockets, bearing change...I recall and still not sure the setting placement of the slide rail, does it just touch chain when positioning or give it a little pressure against chain? Tony mine has single chain, not duplex.

[crguy]

Let me add what I've checked. Thought possibly a lean state on left side giving me a ping at light throttle so checked plugs and both cyl are same. Checked exhaust header nut for possible leak. Checked valve lash and rocker condition, lash hasn't moved since last 3k check. Check timing since never heard this engine ping but just to make sure, in fact I deliberately retarded it just to prove not ignition ping. My bike is naked so I'm not getting reflected sound, it is definitely in front of the cylinders left side but only at 3500 rpm light throttle...thanks for the input fella's.

[Barry]

Seems to me very unlikely to be pinging which would occur on heavy load and usually kick in at lower revs although that might depend when the Alpha can stops advancing. It also has a distinctive sound which is easily recognized due to it being at a higher frequency than the cylinder firing frequency.

I have no idea how an Alpha bean can might produce the noise by mechanical means but I wonder if you have the original one to swap in as a process of elimination.

[crguy]

Good idea Barry, thanks I will pursue.

[crguy]

Just to update it was the chain...thanks to all.