Interesting motorcycles, not XS650

rideitfast

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Been getting in some garage time and my Harley project is getting close to done.
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Adamc

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kshansen

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That’s a great looking machine. Love the colours. Twin disc front end looks really good. Never liked the single disc styling on such a big bike.

I did the twin disk front brake conversion on both my Sportsters that I ran sidecars on. Dealer actually "insisted" on it after I had a cracked rotor on the 1988, also installed a fork brace. That was after around 800 miles with a sidecar. Went on to put close to 100,000 total on that outfit and even put a larger sidecar than the original one and never had another cracked rotor so maybe the dealer was right?
 

MaxPete

Lucille, Betty, Demi, Gretel & Big Sue money pits.
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WOW - I've been around bikes for more than 45 years and was an avid Cycle World reader in the 1970s, but I have never seen the RZ201 before. Obviously, Yamaha dropped it before they lost their shirt on it, in contrast to Suzuki who chased the equally cool RE5 down a very expensive rabbit hole that nearly bankrupted the company.

The problem with rotaries (Wankels if you like) is that they have inherently have poor volumetric efficiency and difficult machining geometries. This results in expensive engines that burn a lot of fuel, have extremely hot exhaust gases (and so they require big stainless steel mufflers) and have atrocious emissions performance (and so they need very large and expensive catalytic converters meet government standards).

As for durability, a Mazda engineer once told me that some RX7 and RX8 sports car engines seemed to run forever with no apparent internal wear at all while others were totally shot within 20-30,000 km (about 12-20,000 miles) - and nobody could figure out why. One outcome of this was that they had to replace A LOT of rotary engines with new units, but the owners hated this because the cars were no longer numbers-matching vehicles and thus, their collectability was significantly reduced.
 

Adamc

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