A Good Ride Spoiled

Tornado

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Did a great bit of riding out to Squamish (about 75 KMs) and along the river in perfect weather, as you can see:

IMG_20201007_1228468.jpg



On the return trip, not more than ten mintues along, just passing a big truck on a hill, asked the old girl for bit more power and something gave up, sputtered and dropped a lot of power. No or little power on tap. Pulled over and a blipped throttle showed lots of smoke, most on left side and lumpy sounding. Shut her down and sorted a flatbed to get her home. Since drivers wont take passengers had to take a $95 taxi to next town where I could take a bus rest of way to Vancouver. Did try waving down lots of passing bikes. One did stop and offered a ride but since hauler hadnt arriveds yet and expected anywhere upto two hours to arrive, he couldnt hang about so long.

Anyway, im guessing maybe a ring or valve has gone? Maybe headgasket? Will do a compression check and inspect plugs tomorrow.

Real shame, she was going so nicely all day. Was only reving around 3-4k when this happened.
 
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I'm sorry to hear this bit of news. A bad way to have the day turn.... Had it happen on a Sporty once.... quick cough and all power gone. Found two dusted pistons & bent intake valves. Almost wound up tight at the time too. Bad things happen fast. Hope you find it to be something minor anyway.
 

Fast Eddie

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That’s a bummer, but it happens with old stuff.

3-4k is NOT caning it by the way, so no need to feel bad that you caused this. Whatever it is was gonna happen anyway.

Keep us posted.
 

baz

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That's a shit , sorry to hear that!
Keep us posted with the autopsy
Cheers
 

Derek Wilson

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One of my greatest fears. I know my day will come too. Hope it is nothing too serious. Keep us posted. Fingers crossed here.
 

TomU

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Anti-sump valve?

It sucks getting stuck, but looks like the location you got stuck in was beautiful
 

Tornado

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Anti-sump valve?

It sucks getting stuck, but looks like the location you got stuck in was beautiful
Not of the auto spring loaded check valve variety.
Engine didnt seize, was still running as I pulled over and I did a blip or two at roadside to see smoke before shutting it down.
HG makes most plausible explanation as smoke visible out of both non-balance tube pipes wit h a lot more on left side. So whatever happened affected both sides to some extent. No fugly noises other than lumpy idle.
 

baz

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If you were revving balls out 7000rpm or more I'd be inclined to think overheating/seizure/ partial seizure
But at less than 4000rpm?
Can't think what else would lose you loads of power and smoke from both sides
Maybe it is a head gasket as someone already said,but would that cause smoke?
I've blown a hole through one piston before on a triumph twin but limped home on one cylinder 70miles don't remember any smoke
Very intriguing
I'm hoping there's not too much damage to your wallet mate
And back up and running asap
We are lucky with the commando almost every part you could want is available
Good luck with it
 

Tornado

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IMG_20201008_1205150~2.jpg


Left side fouled. Compression test on the cold engine shows 90 left, 120 right PSI. Both were at 125 PSI on warm engine less than 1k miles ago.
Cannot see any obvious external signs. There has been oil seepage at front fins for a while now. Watched pistons and intake valves moving with rear wheel rotation.

Will begin head pull procedure.
 
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I'm sorry to hear this bit of news. A bad way to have the day turn.... Had it happen on a Sporty once.... quick cough and all power gone. Found two dusted pistons & bent intake valves. Almost wound up tight at the time too. Bad things happen fast. Hope you find it to be something minor anyway.


Bought a 73 XLCH Sportster used in 1974 with 1400 miles on the clock . I was riding down the road one day minding my business and bang the big end seized up on me and with the ten over tubes on the front it darn near put me on my can and the mileage at the time of the dastardly deed was 1600 miles this was a expensive used 73 Sportster.

Mark
 
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