Yamaha frame building.


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When I made the extended manifolds for the 74 and added VM 34s, I noticed something odd with the frame work: The engine is located a few mm off centre towards the left side. At first I thought it was my engine brackets, or the manifolds were slightly off, but, the middle lower and rear lower brackets are what position the engine in place and the manifolds are true to the inlets.

Despite Yamaha's abysmal metalwork, there's no way the frame could bend between these two mounting points. So, obviously their frame jigs were out by a few mm. Not surprising I suppose when you look at the build quality of the frame, I'm pretty sure the five year old next door could have done a better job of making a frame.

You won't notice this anomaly due to the position of the standard BS carbs, but as my extended manifolds position the carbs either side of the central dowtube, the right hand carb has to be angled slightly so it doesn't touch the downtube.

Doesn't affect the bike at all, just an 'untidy' anomaly, but being a very tidy bloke when it comes to building bikes???


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I believe a lot of motorcycle makers fit engines offset, usually to the left, to get the desired alignment of front and rear sprockets with the chain avoiding the tyre.
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