GB is not OK, again!

[Greybeard]

After adjusting the clutch this evening I took the bike for a gentle pootle. Got about a mile away...Bang! followed by a fairly heavy rattle. I very gingerly rode home, the engine was running just as smoothly but sounded horrible. I've taken the drive side cover off to see if it was anything to do with the clutch as I'd just been in there; that all appears normal. I've come indoors now and made myself a stiff drink. I'm thinking big end failure. I'll fess up and tell you that I reused the big end bolts that I put in new 6 years ago. Oh well, it looks like I'm destined to miss another BSAOC camp! 

[a10 gf]

Damn  My sympathy. Courage, you'll find the problem (...and make another educating topic for the good of other owners).

[Triton Thrasher]

I don’t see how re-using bolts would make it go bang in the first five minutes, but we’ll see.
Did it have good oil pressure when you started it?

[RoyC]

Oh NO, not again.    You are making me very nervous about taking my bike out for a run.

[duTch]

 Hmmmm, not good- where's the fat lady   It's her fault 

 Hope it's nothing major- or you'll become an expert at  'stiff-drink' mixing reviews too 

[Greybeard]

I don’t see how re-using bolts would make it go bang in the first five minutes, but we’ll see.m
Did it have good oil pressure when you started it?

In a hurry to get out before dark, forgot to look in the tank.

[KiwiGF]

After adjusting the clutch this evening I took the bike for a gentle pootle. Got about a mile away...Bang! followed by a fairly heavy rattle. I very gingerly rode home, the engine was running just as smoothly but sounded horrible. I've taken the drive side cover off to see if it was anything to do with the clutch as I'd just been in there; that all appears normal. I've come indoors now and made myself a stiff drink. I'm thinking big end failure. I'll fess up and tell you that I reused the big end bolts that I put in new 6 years ago. Oh well, it looks like I'm destined to miss another BSAOC camp! 

Don’t run it until you have checked if it’s serious! Hopefully it’s not though. The attached pics (not my A65, thankfully) are from a bike that just had a rattle, no smoke, and which we stood around revving on it’s stand to see if it could still do the rally run. Makes me cringe at the extra carnage we may have caused. Piston had broken was the diagnosis when it got back home (via trailer).

[RichardL]

GB,

I think you know we all feel horrible for you about this. I think of you as a person of determination, so I expect you will be back to it soon. Maybe a couple of days off to take in Spring. You know what they say, "Stop and smell the roses," then get back amongst the oil. Wish I was close enough to help.

Richard L.

[Black Sheep]

I took the A10 off the road when it suddenly started making a knocking noise on the way to work one morning. 17 years later, I decided to tackle the engine strip. Off came the outer primary chaincase to reveal - a slackened off cush drive nut. That's all that was wrong. Just as well the A7 was running perfectly all that time. Fingers crossed your problem is as easily sorted.

[RogerSB]

Oh no! I can't add anything except .

[Billybream]

Followed your experience with interest, and was overwhelmed with the forums support, stick at it, here's hoping it's something simple and you get back riding her again shortly.

[muskrat]

G'day GB.
BUGGA Back to the drawing board.
I doubt a loose cush nut would start with a bang. I know you would have cleaned everything but could it have been a missed piece of the errant little end hiding in there to jam a pinion. Next step would be to look inside the timing cover.
Big end bolt is possible but I used the same original (1957) bolts in my race A7SS for 8 years in numerous rebuilds doing 8 grand and 14:1 comp. Snapped a few cranks and lifted a few barrels but never had a big end let go.
To get the right answer this time quicker you need to offer more than a kiss .
We're all rooting for you.
Cheers

[Greybeard]

To get the right answer this time quicker you need to offer more than a kiss .

I'm braced!

[duTch]

 I know I'll be up early counting the stars again, and lucky had too-good-a-deal at the bottlo the other day so...just exactly what kind of 'bang' and 'rattle' was it....from where-ish...?

 Rattle and Hum is almost acceptable, but Bang and Rattle didn't really make the charts

  I snapped a crank once and it would've also got me a few Km's home, except we were still in miles then...and it got me home

[bsa-bill]

Commiserations GB