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[Tim NZ]

The worst of 'running' the main bearings is seen on the timing side (the timing side wears worst if the crank is 'out'). By the time you can hear the bearings rumbling, the eyes in the flywheels will have already fretted oval. Plus there will be evidence of immense stress risers on the flanks of the crankpin just inboard of the thrust washers. Right at the edge where the Flywheel sits.


The easiest way to gauge how bad the fretting is is to simply hand sit the old crankpin back in the eye. If it freely enters the flywheel deeper than 1/4" you have a real bad one...


Not renewing the crank pin when the main bearings have failed is also likely to see the crank pin snap off through the Oil way drilling on the timing side. (I have several such crank pins)




Why does all this happen?


Well, too many of the Indian made bearings are shite. There are sooo many rip off pirate versions of reputable brands available in India. Situation is made worse for the 500 due to the heavier piston. But mostly I believe that it happens from a poor initial fit of either the crank pin, OR the main bearings, combined with over-reving the motor?


I have examined brand new cranks and found leaky Oil Pressure relief valves, Oversize crank-pin fitted from new, different diameter crank pin sides, loose main bearings, offset small end eyes, Oval Con rod eyes, Con rods that look like they had been fettled with an angle grinder...


The 350 is not so bad, as the floating bush usually either fails due to a stripped pump worm, (too many kickbacks when starting) a knackered quill seal, (often a precursor to stuffed main bearings...) or worn out oil due to too long an oil change interval. Evidence of oil breakdown and cavitation is often seen on the floating bush if you catch it before it has flogged itself to death...

[nickbarber]

Interesting read Tim, thanks for that! always good to talk to someone across the ditch in NZ. -Nick

[Waltr]

So Tim, have you been inside a UCE engine and found the same?

[Tim NZ]

The UCEs have a much larger dia and longer crankpin, same assembly as in the AVL motors, much stiffer, and do not have any where near the same number of potential problems.




The UCE have other 'issues'...

[Adrian]

Tim,



I'd be interested to know what those UCE issues are, if that's not the subject for a different thread. I am well aware of the best-known failings of the 500 AVL Electra-X, having collected the full set.



Do your comments on the classic Bullet cranks also apply at least in part to Redditch cranks too? Quality control my have been better to start with, but of course these cranks are now over 50 years old. There was a 500 big head Bullet on ebay a few months ago with a crank whose big end had come undone (I was tempted, factoring in the cost of one of our hosts' performance crankshafts). Fortunately I missed the close of bidding, being parked up by the roadside 5 miles from home having to fit a new clutch cable...



A.

[Tim NZ]

The Redditch Built-up cranks face the same issues as the Indian counter part, be aware that the pre '72 Indian motors still have the old imperial Built-up bearing for the timing side, which is a stronger assembly; a stiffer crank shaft assembly.


Ultimately it is about; Fit for purpose, and build-standards. The basis for the Indian bike has 70kph being considered FAST, so it was built with that as one of its principle Build requirements?




To generalise, the Bikes being made pre 99 were a grossly inferior item, and the Share holders (including Manganese Bronze) were happy to take what ever profits and dividends they could at the expense of production quality. If some one still has a Pre 99 bike that has not been rebuilt, I'd wager it is a rare beast? When they 350 was first introduced to the Uk and Europe in the late 70's early 80's to get 5000 miles out of a bottom end was considered exciting news! To put it bluntly, for the most part they were crap...




I believe that the issue with the early Electra X cranks was related to inadequate crank pin hardness, and poor engine breathing. It was not uncommon to drain 200cc of water from out of the Oil tank of a post 2003, when the bikes were used for short runs about town. Killer!
(Only about a dozen Electra X's came into NZ, and I am aware of three of them that have died as a result of oil degradation)
Poorly designed and set-up breathers used to see the primary chaincase being over filled with oil, the Air filter and Carb choking on emulsified oil/water puke. Low oil levels in the tank and with the bottom of the oil tank deep in Sludge. The resultant seriously degraded oil lead to an abraded crankpin, dead rollers in the Big end and stuffed cams and followers.


I have the remains of two dead Electra X cranks, both conrods are fine, (relatively) but the crank pins and rollers are seriously fornicated.


If you want to kill the Big end in a UCE, (same Big-end assembly as the AVL/Electra X) extend the oil change intervals past 5000km, and use only the cheapest Super Market oil you can get your hands on; inside 30-40,000km will see it fried. Sooner if you Lug the motor.


At least one can now order spare parts for the crankshaft, for a long time only a complete replacement assembly was available.