I went to this good event, rode to portsmouth-santander.
rode santander-biaritz-calais.

So many problems occurred.
cush drive nut came loose and was gouging the primary. fixed roadside.
prmary chain went all baggy
lights died
magneto cam plate screws came out
magneto came loose
ran out of classic oil and had to use modern 15w40 from petrol stations
bike spewed oil like a breached tanker.

as we neared calais the bike was using so much oil it needed topping up every 150k there was blue smoke on deceleration. I noticed the magneto was moving around quite a lot. the oil smell was pungent and was of a burnt nature. there was no compression in the engine.
then it died at calais. I took the top end off and
the piston is melted.


not sure why it all went so wrong. I suppose with the mag working loose and the cam plate screws losening the timing was messed up and became too advanced. doesent explain the blue smoke on deceleration and the oss of compression prior to all this tho.

Hi Maxwell, not sure what you mean by "cam plate screws" I thought it was held by a sprung wire circlip on your bike.

Its also unusual for a mag to come loose as the straps don't normally stretch. I did see a mag on a BSA wobble arround while running & it had been fitted with no free play between the drive gear & engine idler gear & the armature end was actually trying to bend when the mag fixing straps were tightened, causing a horrible whining noise & a wobbling mag.

When the mag was fitted, was care taken to shim it correctly?

15W /40 is what I run all my BSA's on all year round.

Shame you didn't complete the trip, wasn't that exactly what happened to the last piston recently?

contact breaker plate? basically the screws/nuts that are visible from the points end vanished bar the long one with the clip for the points cover.
yea the previous piston ciesed from being too lean so I had it a bit rich ever since.
I think the strap bolt has vibrated loose. My bike has no head steady and vibrates quite a lot, every stop we made something had come loose. at one point the carb had come loose! are you using modern synthetic 15w40?

when fitted mag didn't need shim, no whining or wobbling. everything was fine untill about 800k into the trip. then noticed lack of compression, stench of burning oil, and then death to piston

Not fully synthetic oil, I use 15 /40 in them yes.
Oh, I see your mag body end casting came off, I wonder if it should vibrate that much even with no head steady, wonder if your piston is off weight by a long way? ? ... That's a fair few miles it managed though isn't it.

yea a fair few mies, needless to say I was well and truly saddlesore! yea maybe that's the case. bike's not really configured for long distance. it performed well on the 'twisties' around biaritz etc but yea long haul kicked its ass. smashed it to bits i think we stuck at 65mph to 70 ish, like 110kmph

I would say your timing was probably incorrectly set and your holed piston is the result..also the mixture will have been weakened if the carb came loose which would cause overheating and not help...
It seems to me..and you probably won't like me saying this...that you need to start again with the engine and assemble it and set it up correctly..Also fit a head steady..it's function is to stiffen the engine/frame assembly and reduce vibration..
You can't just throw an engine together and expect it to perform properly..I did 450 (motorway) miles in a day on my 600cc B33 at a steady 60-65 with no problems...the bike should do a trip like that easily if everything is in good order...Ian

email (option): ian@wright52.plus.com

I dont blame You for thinking my engine was a bodge up but I can assure You I put the thing together with the gratest of care and observed all correct procedures. I set the timing quite obsessively as well.
The bike ran like clockwork and was super super fast.
I have done a good few hundred miles since rebuild and until recently it was great.

Head steady - The lug has been removed bu previous owner.

carb - Tightned roadside.

I think the timing got messed up when the mag screws fell out (mag was not done by me)

we did a lot of hard and fast riding in france and spain (couple of competitive speedy mountain runs!)

Greetings Maxwell,

I presume this to be a blog about the event you mentioned....and a picture of your bike included..

Cheers,

JDE



http://thevintagent.blogspot.com/

email (option): teladelujo@msn.com

yes that's the one!
I dont want to spam up this place but there are also some nice event pics on my site here if your interested
http://corpsesfromhell.blogspot.co.uk/