Main Motorcycle: 82 T140ES
Join Date: Dec 2014
Location: San Diego
Other Motorcycle: 1969 T100R Brit Rac Green
Extra Motorcycle: Vespa GTS250 (sorry)
Belt Drive Conversion and Electric Start Questions
I bought this '82 T140ES (electric start) in little pieces in many boxes. Somehow I got it all together. It came with a belt drive conversion that seemed to be in perfect condition. Regardless, I bought a new Gates belt, a name I have learned to trust.
It ran great for 100 miles around town, then after cruising on the freeway for 8 miles the engine bogged down and stalled. It was too stiff to kick over, and of course the electric starter had long before broken the sprag clutch. I loaded the bike on my pickup and went home with my tail between my legs. I had always had misgivings about the belt drive so that's the first thing I investigated.
1. The belt drive has a flange only on the outboard side of the crankshaft wheel. Why only one side? When I exposed the primary drive the belt was offset 5/16" inboard meaning that it was not fully engaged with the wheels. The belt and everything are in perfect condition. The belt doesn't have any directional arrows. There is printing on the belt. Is that an indication of direction of rotation? There's no sign of wear on either edge of the belt and no sign that the belt has been rubbing on the aluminum castings on the inboard side. But still it just isn't right. Does someone have advice about a guide surface that could be improvised (or that might be missing) on the inboard side of the belt?
2. Now that I've opened up the primary drive and inspected it the engine turns over quite freely and has incredible compression. When I bored the cylinders I fitted the new pistons and rings with the minimum recommended clearances. I suspect that the engine tightened up simply due to thermal expansion of the pistons. Maybe the engine could stand several hundred more miles of gentle break-in before I push it too hard. The compression is so good that I'm not sure my 190lbs can kick it over. I'll try the trick of bringing one piston to TDC then kicking it.
3. Has anyone yet solved the problem of the freekin' sprag clutches breaking? My electric starter worked well for maybe 20 starts before it broke.
Thanks everyone for your help and advice. I've easily spent 100 hours getting this beast together. It's time to start enjoying riding it.