First mechanical breakdown.

[muskrat]

G'day all
           after 1000 miles on FULLY re-built motor, the cafe had it's first mechanical breakdown. Both RH valves bent ! No not through over-reving or valve bounce, but the ingress of a foreign body.
 I had just helicoiled the RH spark plug hole, as I have done numerous times before, with the head insitu. Did it right with no swarf or tang left behind. Wound motor over till ex valve open and blew out with compressed air. All good.
 The next morning it started first kick. I did notice a faint rattle, but it warmed up and didn't miss. So off I go, 30 mph till I got to the highway (1 mile) then opened her up. 1 mile further she dropped a pot so limped home on one lung. Hmmm no comp on RH side, both valve clearance's 50 thou, head off, yep bent ! How the f, then saw a piece of steel the size of a spark plug screw on cap (the bit you leave on or take off depending on the type of cap) sitting on the piston. OK that's how it happened, how the hell did it get in there ? What is it ?
 Two days later after fitting spare valves and blowing the head off prior to fitting I found the source of the problem. The tip of my air gun was missing !!! Bugga.
 Moral to the story, on completion of work check all tools and sundry items are correct and accounted for like they do in an operation theatre. Now where is my wrist watch ?
Cheers

[bsa-bill]

So how do you reckon this bent both the valves - just bounced around until it got into the wrong place ,between valve and seat?


All the best - Bill

[a10 gf]

Sorry for what happened, but thanks for sharing a valuable reminder to be careful.
I guess this > sums up your reaction when finding the cause.

[Brian]

Jeeez Muskrat, you would have to be pretty unlucky for this to happen. I suppose it could have been worse.

Just goes to show that no matter how careful you are things still go wrong. Whats that old saying about expect the unexpected. 

[muskrat]

 Yes Bill, sort of bounced around till it got my attention. Shame it didn't go straight out the exhaust un-noticed.
 Thanks a10gf, yes after two days of racking my brain, thinking of a thousand ways a piece of steel that size got in there.
 Brian, must have been all those mirrors I have broken splitting lanes.
I am usually meticulous with engine work. Shows what can happen if you let your guard down.
 About 20 years ago I had a small (1/8") ball fall down the mouth of a car (mum's) carby un-noticed. It worked it's way from one cylinder to the next and next. Didn't hurt any valves but poch marked three pistons before exiting the exhaust.
 Anyway, fired her up today. A little weak on that side due to a small mark in the bore, but cracked the TON no worries. Still having fun sorting these carbs, getting close.
Cheers