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Blew up my motor

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NinjaBob:
Noting my last post in Garage can it be a coincidence???
I was accelerating hard, in 4th gear I think, on a back road about 30 miles from home when my 09 Concours 14 just died. My first
thought was that I had hit the rev limiter and quickly upshifted but the oil light was on and the engine was dead and I was coasting. I downshifted to match my speed and let out the clutch to bumps start  it but nothing. I coasted to a stop and tried the starter which spun at higher than normal speed. I immediately sensed that I had a major problem.


A couple of pickup trucks passed before a good samaritan came along on his Honda Shadow with is young son on pillion. They lived nearby and went and got their truck and trailer and took me and the bike home 30 miles.


I sought help on two Concours forums, posting an audio recording of a starting attempt. All the knowledgeable subscribers, including three pro mechanics agreed there was no compression. I first removed the timing cover to access the crank bolt to turn the engine. There was a tooth broken off the timing rotor. Removing the valve cover I discovered both exhaust cam sprocket bolts sheared of. Ex valve buckets for 3 & 4 were abnormally low, suggesting bent valves. 1 and 2 buckets were way high and removing them revealed both valve had dropped.


What caused it? The obvious first culprit in my mind is the valve adjustment work, but it ran great for 500 miles after that. The evidence seems to me to suggest over-revving. In half a million miles of biking this is the first engine I ever blew up.
 

brider:
That just sucks.  I would lean toward the valve adjustment process too.  Something either didn't get torqued right and backed off  or failed when torqued and gave way later.  I'm no expert but I did stay at Holiday Inn all week.  ::) How many miles?  Only engine issues I've ever had or heard of out of the Concours was in 2000 when they had that soft cam lobe issue.  That was fixed under the warranty.  Any chance you have a warranty recourse? 

OldButNotDead:
Trouble shooting on the web is really shakey.   The theme title of blowing an engine is not something I would bet on.  IMO opinion blowing engines are pretty noisy affairs and engine parts tend to put holes in things like engine casings.  My bet is something electrical.  ECU, or some other engine control component.  Although there are sharp guys on Connie forums, I would try a dealer first.

If it were valve job related you would have known it immediately.  BUT, if you disconnected some plug and it came loose later, that could do it.

NinjaBob:
Just under 30,000 miles. It is an 09, no warranty. I have removed the valve cover post mortem and clearly have valve damage.
I assume when the cam stopped turning the pistons hit the valves, at least in 3 & 4.
There is no sign of damage to the cam bearing surfaces so does not appear the cam seized. But something major had to happen to shear the cam sprocket bolts. I am amazed I did not feel anything, except the motor die. I fished around in the sump with a magnet looking for the timing rotor tooth and found one of the sheared off bolt heads.


To remove the valve cover for the post mortem I had to go through all the same steps for the valve check and did not find anything out of order.

TN2Wheeler:



--- Quote from: NinjaBob on May 20, 2017, 08:15:09 AM ---...
 I first removed the timing cover to access the crank bolt to turn the engine. There was a tooth broken off the timing rotor. Removing the valve cover I discovered both exhaust cam sprocket bolts sheared of. Ex valve buckets for 3 & 4 were abnormally low, suggesting bent valves. 1 and 2 buckets were way high and removing them revealed both valve had dropped.
...

--- End quote ---

Bummer. Pretty sure that ^^^ rules out electrical issues.

Of course this should not have happened, particularly not at only 30K miles. I know many of these bikes seem to go on forever.

My personal experience with Kaws has not been great. I not owned many Kaws however on 2 of the 3 or 4 that I've owned they failed  catastrophically.  They didn't just quit running - they broke a lot of internal parts making for very expensive repairs. i.e they "blew up".

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