I've weighed in on this before. P.E.I. always insisted that the barrel should be clamped by the crankcase mouth, but what would he know!
Misc: Oil Oil Seals on inside of Comet-C Timing Side Cover
- Thread starter Joe
- Start date
Its not the first time I just had a barrel being bored out to find that in the area below where the crankcase mouth is the barrel 'bells' out and could not be cleaned out to +40.
I certainly dont worry about oil feed to the barrel but then racing clearance is 6 thou and I am asking 4.5-5 for my next road twin.
I certainly dont worry about oil feed to the barrel but then racing clearance is 6 thou and I am asking 4.5-5 for my next road twin.
I think that clamping the barrels with the case is a poor way to proceed. I have never done it, but I certainly do not know as much as P.E.I. The liners are too thin to clamp at the waist and the crankcase will distort the liner significantly. Some builders "hot hone" their cylinders in the cases to avoid this, but that seemed too complicated to me.
I have had good luck with ten thou clearance for the crankcase spigots, but it is too big a gap for the oil to transfer through the liner hole. This was a good reason to discontinue the use of the oil hole. Two of the racing 500 singles have cylinders that were plated 30 years ago and are still being used today as they remain within their stock racing spec. The Nicasil appears to hold up well without oil holes or clamping. The piston skirts were set at 0.0035", with the Nicasil aluminum liners and 0.006." with the nodular iron liners.
David
I have had good luck with ten thou clearance for the crankcase spigots, but it is too big a gap for the oil to transfer through the liner hole. This was a good reason to discontinue the use of the oil hole. Two of the racing 500 singles have cylinders that were plated 30 years ago and are still being used today as they remain within their stock racing spec. The Nicasil appears to hold up well without oil holes or clamping. The piston skirts were set at 0.0035", with the Nicasil aluminum liners and 0.006." with the nodular iron liners.
David
I have three Vincents running on the road with the oilholes to the liners blocked. One twin and two singles since more than 10000 miles. No liners clamped in the crankcases.To my mind the biggest advantage beside distorsion is more oil in and on the camshafts. To my mind the pistons don`t need as much oil as most poeple think,there a 2 stroke engines running with 1: 100 mixtures without any problems and doing more than 10000 revs! Erik