Chain broke!

Derek

Derek

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I went for a run with son Niall yesterday.Up to Kirriemuir, along to Blairgowrie, up Glen Shee turning off at Dalrulzion to Kirkmichael and over the Moulin Moor to Pitlochry. Stopped threre for a coffee before continuining on to Aberfeldy and on towards Crieff. We were a mile or so over the top of the hill from Aberfeldy and I had just overtaken a couple of cars when all of a sudden I had no drive! I knew right away what was wrong - the chain had come off. :eek:
While we waited up on the moor for the breakdown to come I retrieved the chain. One side plate had broken through the middle and the opposite one had bent, the twisting force pulling it off the rivet. I was extremely lucky that the chain came straight off with out hitting anything or jamming up in the gearbox sprocket with potentially disasterous consequences.
Years and years ago I had a chain break on a BSA A10 Road Rocket, but it was shagged and deserved to break. This was a gold X-ring Tsubaki with 12,300 miles on it, always run with a chain oiler and no tight spots. Both sprockets are in very good condition. I have no idea why it broke :confused: I would have expected at least another 5,000 miles from it.
Anyway, that's me off the road for a few days until I get another one. An expense I could have done without right now, I'd just put 2 new tyres on the car that morning. :mad:
 
I think the chains are a bit light for the power anyway. One of our crowd on a 750 monster had his chain break in Holland and it put a hole in the crankcase, engine goosed and had to tow him to the ferry.
 
not good when it happens but at least it didn't take a crankcase with it!

how good is the sprocket alignment Derek? If the rear is off line it can twist the chain which over time causes side plate problems or popped rivets, i bought one of those laser tools and was amazed at how accurate they are, i thought i could line it up by eye/straight edge but this really does get it spot on.
 
Remember to do the lottery......mind you if you were that lucky it wouldn't have broke! glad you're ok though.
 
Gizmo said:
not good when it happens but at least it didn't take a crankcase with it!

how good is the sprocket alignment Derek? If the rear is off line it can twist the chain which over time causes side plate problems or popped rivets, i bought one of those laser tools and was amazed at how accurate they are, i thought i could line it up by eye/straight edge but this really does get it spot on.
Click to expand...

Interesting point Michael. I'm sure the wheel alignment is 100% spot on, if the rear is offset you notice that the bars aren't straight when riding in a straight line and my MoT man has a bee in his bonnet about wheel alignment, but that doesn't necessarily mean the sprockets are in line and there isn't a lot you can do about that. The front sprocket is fixed in it's position at the gear box shaft and the one is similarly fixed at the rear wheel. One assumes that the manufacturer's wheel spacers lines it all up but do they? I don't really think that wheel/sprocket alignment was the cause though. I wonder if it is worth investing a few pounds in one of these crankcase protectors?
 
the lines on the swingarm aren't accurate Derek, they are a guide but it needs a check. I know most sprockets have the correct offset but on my Laverda you need to make sure you match oem with oem as it has a slightly different spacing to the after market sprockets. Only by a few mm but its enough to put pressure on the chain. One of the other things to watch is making sure chain is slack, the slack is there to take into account an increase in chain tension as the swingarm goes through its arc, i set mine up with rear shock out and wheel raised up just to check. you can then use same point with bike on sidestand and know its slack enough. on a tourer which can run loaded/2 up ts really important as if suspension is compressed and chain is on the tight side to start its going to increase the tension
 
Commiserations on your broken chain, Derek, and glad you weren't lashed by it.

By a strange coincidence, I recall someone else's chain broke on that same stretch of road a year or two ago - on a Scottish Ducati Group run (just before DUN came into existence). The only time I've seen it happen. Very strange.
 
Check this out.

I posted before but the pic didn't come through, this was on a virtually new chain....and if not corrected would certainly have broken sooner rather than later....

..and this was the original Ducati factory rivet. I use a Japanese "Whale" tool which gives a better result IMHO.

BTW broken crankase is not the worst possible result..a broken chain can take your leg off. So check your rivets.

Take care,

Frank
 
Bad news Derek but I'm glad you are unharmed - and the bike too.
I was promising to have my chain replaced this year but out on a run recently the chain decided it had had enough too and came off! It's a strange feeling when you know what's happened as you have no drive.... and you are waiting for the unkown ....... but meantime trying to stop as quickly and safely as possible :eek:
fortunately no damage done to the bike or me either.
 
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