DT1 flat track project

Getting ready for more engine assembly, I bought a gasket set from ebay seller Vintage MotorCycle Parts Warehouse.


I'm waiting on a new clutch flat bearing, so I've been doing some clean-up on the clutch cover. A little more work and it will be ready.


The stock Autolube is the only way to go on a street bike, but since I will be using pre-mix I bought a block-off for the oil pump.


The DT2 engine in the bike for mock-up had a standard cylinder, but would have needed an overbore anyway, and I figured it would be nice to have a spare, so I bought another cylinder for a $42.92 'buy it now' on ebay. It has what looks like a nicely done mild port job, so I'll likely end up running it.


Here is the exhaust port on the standard cylinder.


Here is the cylinder I just bought. It was listed as being for a '74 DT250, which is a completely different bike and engine from the '68 to '73 DT1/2/3 series, but I could tell from the pictures it was a '72 or '73. The stock bore is 70.00 mm. The Yamaha oversizes are 70.25, 70.50, 70.75, and 71.00mm. Wiseco has 70.50, 71.00, 71.50, and 72.00mm oversizes. The one I bought is currently at 70.75mm. It measures loose, and would rattle bad, so I'll take it in and see if it will go 71.00mm, which would still give me two oversizes to use.