[ace.cafe]

IF the bore and rings are the issue, I recommend going +.010" bore and new +.010" piston/rings.

Let's face it, the OEM piston is a piece of crap, and so are the rings. It's a good opportunity to get that stuff out of there, put a fresh bore/hone on it to get the correct clearance, and bed in the fresh rings. There is no good reason to retain that OEM junk. Believe me.

[Black fingernail]

IF the bore and rings are the issue, I recommend going +.010" bore and new +.010" piston/rings.

Let's face it, the OEM piston is a piece of crap, and so are the rings. It's a good opportunity to get that stuff out of there, put a fresh bore/hone on it to get the correct clearance, and bed in the fresh rings. There is no good reason to retain that OEM junk. Believe me.

I couldn't agree more, my bore is ok, I'll be staying standard, but a forged piston is going in, with a light hone, new valves & springs just to make sure, and I'll put it back together carefully with new gaskets, washers, etc.
I noticed that the rocker feed pipe has had a straightened out kink! so that is being replaced also.
I do not understand why the oil control ring groove has been sliced in such a manner on the OEM piston, would it not have been better to drill it like everybody else?
I am not in a great hurry to get her back on the road, I am taking my time, so I am unashamedly taking advantage of a good friend of mine who likes to polish aluminium casings, he has just done the rocker covers, and has taken away the cylinder head, I'm intrigued as to how that pans out! When the head is back, I'll give him the timing cover!

[Adrian II]

It's quite common to tart up the cylinder head casting by carefully removing all the casting flash and generally tidying up the fins, then polishing the fin edges, ideally after the head has been vapor/vapour blasted. Once that has been done, you'll need an alloy barrel finished to match. 

A.

[ace.cafe]

Just be careful with clearance on that forged piston. It needs noticeably more bore clearance than the cast piston did.

[Adrian II]

That was certainly true with the Accralite high-compression pistons a few years ago.

A.

[AzCal Retred]

Anodizing comes in a wide variety of colours, if you're going for flash...shouldn't adversely affect heat transfer either. 

[Black fingernail]

It's quite common to tart up the cylinder head casting by carefully removing all the casting flash and generally tidying up the fins, then polishing the fin edges, ideally after the head has been vapor/vapour blasted. Once that has been done, you'll need an alloy barrel finished to match. 

A.

I'll just leave him to it, lucky for me, he is very OCD!

[Black fingernail]

Just be careful with clearance on that forged piston. It needs noticeably more bore clearance than the cast piston did.

Thanks for that, I'll measure it carefully, how much clearance do you recommend?

[Adrian II]

Check with Mr H, I think they had to issue revised instructions!

I'm not sure anodizing works that well on cast alloy.

A.

[ace.cafe]

Thanks for that, I'll measure it carefully, how much clearance do you recommend?

It depends on the piston, but generally they need at least .005" but not more than .006". The maker should give specs, but sometimes those specs are for water cooled applications.
Beware of any forged piston specs calling for less than .004" clearance.

It comes down to how dense the forging is, and how much material is located on the critical expansion areas to soak up heat and expand.
For our Ace piston forged from 2618 and plenty of lightening machining, we could do .005" if we were very careful about state of tuning and controlled break in.
However, at .006" we might get some piston slap, and at .0045" it might seize,  so it is a tight window for clearance.

[Black fingernail]

Just an update.
The piston and rings are fitted, nicely honed cylinder ( to suit piston clearance), fitted with new base gasket.
I'm just waiting for Big Al. to finish doing whatever he is doing to the cylinder head, he has informed me that one of the old  valves was not seated to the collets very well, It seems he is cleaning up the ports as well, I'll find out on Monday.
Now the cylinder is sorted and I am awaiting parts, I'll get the primary casing off ready for Al. to polish them when he brings the cylinder head back. I have got an 18 tooth sprocket ready, and a foot of 'o' ring chain (off cut from work), so I can see if a full 'o' ring chain will fit.
I'll take some pics as things go on.

[cyrusb]

Not so sure the Oring chain will clear the inner primary cover. The master link pins contact the inner primary with a standard chain.Thats why my stock machine had the link installed the "hard way" with the clip on the inside.  But with a Bullet, who knows, you may have the room. Also a 19t drive will eliminate the half link.