So, here I am with an empy engine case with the # that matches my frame ( thanks to Ken C. in Chilliwack, BC - long story). Task at hand is to move the inerts of the currently installed engine to the "new" engine case to make this a matching numbers R60/5.
Now as with all things, you think about improvements: the 750cc piston/barrels/head are a given as they are there. Consider that a reasonable upgrade that won't even offend the collector.
Now, there is the 336 sport cam that was originally developed for exactly this 750cc engine and there are 900cc barrels/pistons/heads that you can make fit.
I am looking at four scenarios/variations:
Option 1: do a 1-to-1 swap and be done with it (min $$$)
Option 2: add a 336 cam to the 750cc engine (since the cam has the flat asymmetric keyed interface that also requires the use the later timing cover, points-in-beancan, 107mm alternator etc) (option 1 + 336 cam)
Option 3: add 900cc barrels/pistons/heads and use everyhting else as is (option 1 + 900cc)
Option 4: option 3 + 336 cam (max $$$)
I am torn between the two extremes (as-is or 900cc with 336 cam) but the problem I really see is the following: if I have a 900cc engine, it will accelerate faster and I will get into situations far more easily where good brakes save lives. Is a well adjusted and maintained /5 front duplex front brake up for the job? I have heard it beats the single ATE but have no first hand experience myself.
Is the 750cc engine with the 336 cam a worthwhile (as in noticeable) improvement? Also, does a 1979 timing cover with single chain fit the /5 housing, does the later flat keyed cam (1979-on) fit the engine case when used with the correct inner rotor?
It being a R60/5, would the options 3 and 4 be considered over the top upgrades by collectors (not that I intend to sell it ever but you never know there might be situations where an emergency sale has to be considered)? In other words, will the value be affected? The color is Monza Blue Metallic #538 which is correct for a 1972 R60/5, but the original painted parts I used were a contribution from my Dad, and were not on the bike originally.
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I will install the matching engine case into the frame, that's for sure! In the process and since the case is empty, I will learn about installing camshafts and crankshafts and by that complete my apprenticeship on Airhead engines by reaching the final frontier, a rebuilt engine from an empty case to full completion.
Would like to hear about your views/opinions/lessons learned etc., technically and philosophically!
Thanks, Stephen