6 replies to this topic

[eiaprilia]

Hi peeps
I stripped the engine of my cota last night as she had a very slight rattle, the small end has a tiny bit of play so i've decided to change piston & rings etc while the engines open. I phoned BVM today but they didnt recognise the code on the piston head? They said it should have an A,B or C on it, mine has 7w ? I tried phoning Sandifords but they were closed. Can anybody shed any light on this one for me? The code on the barrel is 7 x B 03

Thanks in advance

[tt5th]

Easiest thing to do is just do a top end swap. Send off your old barrel and they will send you back a nice newly nicosil coated barrel with matching piston and necessary bits.

Sandifords will do it but I got mine from Feetup Trialsport near scarborough. Not sure about Sandifords but Feetup just add a tenner on from what it costs them to cover the cost of keeping it in stock.

Otherwise you will need to buy a new piston and send it and the barrel off to Langcourts to be coated and matched. I wouldn't change a piston without getting the barrel relined.

Sandifords and Feetup both offer spot on service.


EDIT: In answer to your original question my piston also didn't have a normal code on it. Both sandifords and feetup didn't seem to worry about it they just swap the whole thing over. After mine was done its tight as anything, well worth the money. What condition is the cylinder? Any scoring or dark lines? Can you still see the crosshatch honing?

Edited by tt5th, 17 June 2008 - 06:41 PM.

[eiaprilia]

Interesting thanks for the speedy reply

the barrels still nice and shiny, looking at it again there are a few dark lines down it only one or two, i put the top ring in it and measured the wear all the way down, its totally even at 14 thou ring gap. How much did the whole barrel swap and piston replacement cost you if you dont mind me asking? I could just chuck in a new small end bearing and a set of rings to get me by, just back from biking holiday in Norway and bought new leathers etc so moneys a wee bit tight at the mo.

Cheers again

Ian

[tt5th]

Cost me £250 or close as for absolutley everything. The exchange cylinder was £135 wheras Langcourts will coat yours for £125.

Piston is about £70 on its own.

Rings, gaskets and small end bearing would be about £32. If it were me in your situation I'd do these for now then do a proper job when you've got the cash.

[eiaprilia]

thanks dude think i'll be going for the cheaper option at the mo, ive got a rotax motor to rebuild as well so the money would be better spent on that

[tt5th]

In fact I even quoted for a gasket you won't need, so it'll be £3.75 less.

The top gasket is metal so most people reuse it.

[TooFastTim]

Piston Code? Is that Dan Browns latest book?