Cylinder sleeve question

Hi the notch on the Commando is for the throw of the conrod the chap who resleeved my barrels put them back in .But i dont know much about the early ones.Why dont you loosely fit Barrel without rings on the pistonand turn it over

Cheers Steve

Hi.

I think this 'notch' is there to aid fitting the piston rings into the bore when slipping the barrel on - thats what I use it for!

Regards.

Ian.

I think it is there for the same reason as in the commando as described by Steve. My 36 inter has the notch and when I got it re-sleeved the guy put the notch back in.

It's just the same as my 1949 ES2

See attached photo

As the "notch" hardly goes through to the outside, I would say it was for clearance of the conrod.

I think it's fair to say that the small diagonal notch shouldn't be there. Having said that, it probably didn't do any harm - it might even have held some oil on the cylinder wall. Fitting the cylinder liner should restore your bore to normal. At ease, sergeant! Gordon.

I think you'll find that 'diagonal notch' is actually an oil feed hole linked up to the cylinder base flange. It's fed from an oil pressure relief ballvalve in the timing case.

Cheers.

Ian.

Mt knowledge is based on the pre-'38 pattern side valves but I believe that the OHVs used the same system - The 'notch' is the exit hole from a drilling which begins on the cylinder flange at the rear and travels diagonally up through the cylinder before exiting in the lower part of the bore.

It is esssential for the cylinder wall oiling on the earlier models and originally was controlled by a regulator screw.

I'd check to see if it is a drilling on yours and more importantly if it lines up with an oil feed on the top face of the crankcase. If so then it needs to be reinsated after sleeving, as per the conrod clearance slots.

Looks like plenty of meat in that barrel. Why do you think that it needs a sleeve instead of an over bore?

If you do sleeve it, does the sleeve have the cutouts for the conrod clearance? You will have to drill the sleeve before installation being sure to index the sleeve to the cylinder so that the hole you drilled in the sleeve will line up with the old oil notch. The hole does not have to be in the existing diagonal shape but if you want to elongate it a little dremel work will do nicely. The piston oiling hole in the later singles (my '61 Model 50) is just a circular hole

If the notch in your barrel is an oil feed (quite possible - as on my Rudges), you should be able to force some oil through it and see where it comes out - the cylinder base flange presumably. Or indeed, squirt oil into the oil feed hole in the cylinder base flange and see if it appears from your groove. If it is purely a blind groove, it isn't an oil feed, so safe to sleeve and forget. If it's an oil feed, it presents more of a challenge to reinstate once your barrel has been sleeved. A spot of careful measuring would be required. Gordon.