Big End Repair

Ib-Denmark · Post by **Ib-Denmark** » Tue Nov 08, 2005 11:22 am

Hello
The big end bearing in my G80S 1957 need to be exchanged.
It lasted 20.000 miles but now it is knocking to much to make it to the International in Holland and back again. -All summer I was hoping that it was only piston slap but that was not all.-
Now I have heard of BSA-conversion (saw an advertise in Jampot). Is that an improvement or what?
Any good or bad experience?
Can anyone recommend a reliable person that I can trust will be handling my crank as was it his own?

Regards
Ib

Colin F · Post by **Colin F** » Tue Nov 08, 2005 7:26 pm

As far as I know Malcolm Saggers is the only person who does this conversion. The flywheels are remachined to take the BSA type big end which is more robust than the AMC one. He has Alpha manufacture these for him with an AMC size sleeve to fit straight into the conrod.
I have a crank here ready for my next project that Malcolm has modified, I have never hear of one of these big ends failing.

Malcolm's contact details are in the Jampot, he is NOT on email.

Biscuit · Post by **Biscuit** » Wed Nov 09, 2005 5:25 pm

There was a picture of a failed BSA conversation in a magazine some time ago, can't recall which one however. Mind you it probably failed for the same reason as the AMC big ends allegedly fail, the flywheels were not pulled up to the outer sleeve properly, leaving the central pin unsurported.

jonesboy · Post by **jonesboy** » Wed Nov 16, 2005 9:23 pm

malcolm fitted one of his bsa big ends to my ajs scrambler,which has now done 2 seasons,it runs 9.25/1 compresion and is ridden hard,no problems whatsoever,I use 10/40 car engine oil and ancartrige filter on the return

Ib-Denmark · Post by **Ib-Denmark** » Mon Nov 21, 2005 6:37 am

Thank you for your interest.
After talking to you and other AMC-riders I have come to the conclusion that it is a bit a question of what you belive in. I decided to let the danish AMC-Guru Carsten Kyhl do the job. He has now mounted a new two-piece pin of his own manufacture and I am expecting it to work the rest of my life!
Regards
Ib

lawrence · Post by **lawrence** » Mon Nov 21, 2005 6:46 pm

How old are you Ib?????????

Biscuit · Post by **Biscuit** » Mon Nov 21, 2005 7:42 pm

Glance at Ib's bio Lawrence, he is but a youth!!

lawrence · Post by **lawrence** » Tue Nov 22, 2005 6:36 pm

he was chasing girls while I was only interested in Dinky toys. He is an old boy!!!!

Biscuit · Post by **Biscuit** » Tue Nov 22, 2005 9:12 pm

Hmm, where does that leave me?

Ib-Denmark · Post by **Ib-Denmark** » Wed Nov 23, 2005 8:31 am

No man is older than he feel!
As you discovered I am 56 and I an planning to stay her at least until am 100 yers old.
My bike runs 3833 revolutions each mile and I drive around 3000 miles each year. So: when I am 100 the new big end has run 506 million revolutions! No problem! (Half the revs. has no load)
Ib