BSA A50 Pushrod Epic Fail!
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- Опубликовано: 11 сен 2024
- Returning from a trip to a classic car and bike show at Sheringham I completely lost all power on one cylinder.
After getting recovery back to the shed I stripped the top end only to find a broken push rod!
Only question is why did it break?
More checks will be required once I get new pushrods and reassemble.
That's a very strange one. Just as well that you were able to find the fragments. I was decoking my AJS over the winter and dropped a washer down the pushrod tube. Luckily, I could see it sitting on the cam follower and retrieved it with a magnet - phew!
Unfortunate Ian, but at least it didn't impact a valve and piston. Here's to better luck with this bike.
Best wishes, Dean.
I just managed to save the life of my B33 , I found my intake spring had lost virtually all seat pressure, it had 10lbs and its free length was 13mm shorter than the exhaust spring ! . Good luck .
That could have been nasty!
Just stumbled upon this channel. I muck about with old bikes if you clean up the broken end with petrol then put it under a loupe ( I have a cheap USB microscope ) IF it was a crack or a stress raiser ( machining or something ) where the crack started will be polished as it rubs and if I remember principle stresses happen at 90 deg to the load and Im pretty sure there ain't horizontal loads on a pushrod top some side loading yes ! so me thinks it was a stress raiser and or a crack One good thing about these old bike ,,it got ya home and is a doddle to repair !
Yes, would be good to get a closer look at the break.
Dam Ian your not having much luck at the moment I must say I've not see that before but I can say that I've seen loose steel tips, did you have a look inside the rocker cover for any witness marks regarding the tappet adjuster as they do look very long, but having said that it could just be a case of fatigue, but its a one off for me, when you get the new parts you can run the engine with out the rock cover on and you can look and see if any thing looks untoward, there are some molly push rods about that look ok and they have no steel caps, anyway hope you get sorted, kind regards Adrian. ps it could of just bounce off its seat. please take care Ian.
Sorry to hear about your woes Ian.
Do you have any thoughts on why the cylinder was oily? From the video I can't understand why an inlet valve being closed all the time would create so much oil in the cylinder.
Hope you get it sorted.
Andy.
Oil quantity looked worse than it was.
I can only guess the cylinder could act like a suction pump (Inlet stroke not being able to pull in air via the intake) and instead draw in oil past rings/valve guide?
Of course. Now why didn't I think of that! 🙄
I Ian just read on line the a50 has shorter push rods I just typed in a50 push rod problem and britbike forum came up with all the spec for the rods hope that helps. Adrian
Thanks Adrian, push rods are the shorter A50 ones.
I took the head off again and think I have found a possible cause, I will do a follow on video.
I thought the push rod ends were forged into shape?
Hi. Informative video. I’ve just redone my a50 head gasket and found that one pushrod was chipped at the end. Refitted it and now lost the left side completely like yours. I’ve noticed that some sellers are selling a50/a65 rods as the same but after a bit of research it seems they are actually different sizes. Can you confirm this and can you recommend a particular seller/brand etc? Thanks, Mark
@@markhowe1576 yes A50 and A65 rods are different lengths, got mine from Feked but I suspect they all come from the same manufacturer wherever you get them.