24MCS when did hard chrome bores change to iron liners

[Stevefromleicester]

Hello there, I bc am looking at getting another Greeves and its frame number is 61/3712 so that makes it a 1961 Moto-Cross is it 246cc or 256 cc !
anyone know when the early hard chrome bore engines were changed to iron liners ??
thanks
steve Joyce

[johnrunnacles]

It would work out at 246cc on standard bore, Steve. Obviously, a re-bore would increase the cc's. It is my understanding that the hard chrome plated bores were superseded by iron liners after the initial run of the 24MCS model in 1961, although chrome-plated bores may have continued to be available to works riders only.

[Colin Sparrow]

I deal with this in detail on page 86 of my book "Greeves the Complete Story". John is spot on. Greeves changed to austenitic iron liners in 1961. The problem with the chrome bore is that if they are damaged in any way they cannot be re-bored, and Greeves realised that this would not work for private owners. I doubt that there can be any left with the chrome bore still serviceable after nearly 60 years.

[Brian Catt]

I covered the same point in a query on FaceBook a while ago (thanks for the info Colin!). I wonder if there was a power advantage in the chrome bores, or was it just a case of the works boys using up stocks?

[Colin Sparrow]

I daresay there was a perceived power advantage, although somewhere during my researches I found a reference that said the austenitic liner was just as good. They didn't waste much at the factory (apart from iron barrels), so I imagine it was the latter. Or perhaps they were conning the works riders. I imagine Dave Bickers would have taken a bit of conning, though!

Druid might know.

[Colin Sparrow]

61/3712 was a fairly early 24MCS. It left the factory in March 1961. It didn't go to a works rider.

[John Wakefield]

The chrome bore would not wear as quick as iron, but if the chrome peeled off they were scrap. Many continental two stroke manufacturers ie Sach, used chrome bores.

[druid]

I was told a long time ago by someone at the factory that the first chrome bores were very good in maintaining performance. These were a very few for works bikes. When it was tried in production the chrome bores from the platers were a bit iffy. As pointed out a flaky barrel is bad news all round so the factory decided to play safe and not plate the bores.

Druid