Author Topic: Pin dropped into crankcase - HELP  (Read 1243 times)

Online Colsbeeza

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Pin dropped into crankcase - HELP
« on: 01.10. 2018 08:18 »
Oh Dear,
Just when things were going OK - I had rings compressed with new ring compressors (photo attached), had the cylinders dropped on, and was removing the ring compressors when one of the trunnion pins fell out and into the crankcase. *problem*
What a sh--t design.!! - how could a maker not see that happening.?? I had assumed that the trunnion pin could not slide out.
It is about 1/4" diameter x 3/4" long. I cannot see it and suspect it lies beneath the flywheels somewhere.
AND I had the gasket sealer on ready.!!
I had removed the rags to make it easier - and now much harder.
As a first step I will remove the sump plate and try to wash it out or use compressed air to dislodge it.
Anybody had any luck without dismantling the engine?
Col
1961 Golden Flash
Australia

beezermacc

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Re: Pin dropped into crankcase - HELP
« Reply #1 on: 01.10. 2018 08:23 »
removing the sump plate isn't a big job and you've got a good chance of finding it that way. Ring compressors come in various sizes and you should use a size which allows you to undo the screw enough to slip the trunnion over the clip whilst the screw is still in the trunnion, then just pull the compressor off.

Offline LJ.

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Re: Pin dropped into crankcase - HELP
« Reply #2 on: 01.10. 2018 08:24 »
Fish around with a magnetic telescopic pen. I wouldn't use an air line in there could blow anywhere and get tightly wedged in somewhere.
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
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1961 BSA A10  650cc Golden Flash-Red

Online Colsbeeza

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Re: Pin dropped into crankcase - HELP
« Reply #3 on: 01.10. 2018 11:31 »
Thanks Fellas,
Whilst you were replying, I was in the shed. I took off the sump plate and there it was. (Picture)
Yes Beezermac - It dawned on me that I could remove the ring without removing the screw- just undid enough to remove it from its clip. Live and learn eh.? Ring compressor wasn't a piece of crap afterall. *red*
I now have the cylinders and head on - finish tomorrow hopefully..
Col
1961 Golden Flash
Australia

Online morris

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Re: Pin dropped into crankcase - HELP
« Reply #4 on: 01.10. 2018 11:39 »
Happened to me also. Didn’t take long to fish it out with a small flexible shaft magnet.
If you ask me which tool I use the most it’ll probably be that one  *smile*
Afterwards I closed up the eyelet that holds the trunnion to make it a push fit so it wouldn’t drop out anymore. Funny though how something has to happen before you do something about it. I remember thinking that the trunnion was rather loose and I had to watch out for it not to drop in the engine... which it did *problem*
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Offline RichardL

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Re: Pin dropped into crankcase - HELP
« Reply #5 on: 01.10. 2018 12:04 »
You won't find me making such silly mistakes. *whistle* ::hh:: *smile*

Offline ellis

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Re: Pin dropped into crankcase - HELP
« Reply #6 on: 01.10. 2018 18:54 »
Famous last words RichardL.


ELLIS

Offline RichardL

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Re: Pin dropped into crankcase - HELP
« Reply #7 on: 01.10. 2018 19:59 »
All my mistakes are silly.

Offline a10 gf

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Re: Pin dropped into crankcase - HELP
« Reply #8 on: 01.10. 2018 20:17 »
Did this once with a piston circlip. A small nightmare but finally recovered it. Quickly thereafter became an expert in stuffing rags etc into the crank when doing anything.


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Offline jachenbach

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Re: Pin dropped into crankcase - HELP
« Reply #9 on: 02.10. 2018 00:00 »
Can't remember for sure what I dropped in my Bonneville engine years ago, but my brother and I turned the whole bike upside down and shook it until it dropped out.

Offline WozzA

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Re: Pin dropped into crankcase - HELP
« Reply #10 on: 02.10. 2018 02:58 »
I use Musky's method with the plastic drain pipe...
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Online orabanda

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Re: Pin dropped into crankcase - HELP
« Reply #11 on: 02.10. 2018 06:37 »
Did this once with a piston circlip. A small nightmare but finally recovered it. Quickly thereafter became an expert in stuffing rags etc into the crank when doing anything.

The piston clip that caused me the most grief was the one I forgot to install!

The pin acted like a slot drill, and milled a railroad track into the barrel of my friend's hotrod two stroke.

After seeing how fast I had managed to get my DT1 to go, he had asked a big favour: would I unleash my mechanical skills on his TS185?

It was the only time he asked; hasn't called in the last 45 years!

Richard

ps; NEVER made that mistake since!

Rest easy Gavin, all 4 clips WERE fitted into GF#4!

(I think?? *doubt*)



Offline duTch

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Re: Pin dropped into crankcase - HELP
« Reply #12 on: 02.10. 2018 08:47 »
 
Quote
....The piston clip that caused me the most grief was the one I forgot to install!....

 Yep was reminded of same misdemeanor today (/8" groove) while digging out my special tool...  that being a bit of tin cut to shape of the crankcase orifice, but in conjunction with other bits...;

 *Edit*  was originally intended more as something to rest the pistons on though...
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Online olev

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Re: Pin dropped into crankcase - HELP
« Reply #13 on: 02.10. 2018 09:42 »
One of the best bits of info I have got off this forum is Trevor's (BSA_54A10) method of installing rings.
Sit the barrels on the cases held up with a couple of pieces of wood, then hang a dirty great pair of stilsons on the drive shaft so the pistons are presented to the bores.
squeeze the individual rings with your fingers on each side.
The pistons magically slide up into the bore like (can't think of anything that's not rude)
you know what I mean.
I couldn't find Trev's post. He explains it much better than me.
cheers

Offline BSA_54A10

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Re: Pin dropped into crankcase - HELP
« Reply #14 on: 02.10. 2018 09:58 »
Nothing is ever new.
It was a method I was shown by one of the old time racers.
He raced Gold Stars when they were new and on them he used some lengths of garden hose with a slot cut in them ( goldies are through bolted ).
Did not take long to modify the idea for twins.
Better still have not broken a ring in better than 20 years.
If you get a chance to look at the factory promo film you will see that the factory clamped the pistons, put the barrel on top of the clamps then wound the pistons up.
From memory he takes about 6 seconds start to finish.
It is down as a first job for the mill when we get it working.
Bike Beesa
Trevor