Forum

[John M]

[binary]

In the 1953 Hitchcock's Parts Books Online page 5 500cc bullet engine crankshaft, they list an Alpha bearing to fit this crank. Maybe this would be ok.

[John M]

binary, that would be the obvious answer, the slight hick-up is that I have already purchased a RE15 bearing from our hosts and sent it to the crank re-builder, I'm hoping to drop off the crank to-morrow. Due to the unusual nature of my engine I do not know what bearing is currently in there, other than it is a totally knackered floating bush and won't know until the flywheels are split. You would assume that it has the big end to match the early flywheels, but without knowing what the difference is between the big ends, it is possible that it has a later big end. Assuming it is a factory built special they may have fitted the strongest big end available from the current production run. It has also had the oil filter housing damaged and repaired at some time in its past, so there is a good chance that it it is on its second or more big end. I would have a better idea if I knew the difference between the earlier and later bearing.

[Chris Tindal]

John it looks like there's a specific Alpha big end for Model J's and 53 Bullets. I'm sure you could return yours and do a swap.

[John M]

Chris, you are right, in the grand scheme of things it is a storm in a tea cup, it's just the logistics of returning things and messing about, compounded by it being the weekend, as a quick phone call would soon answer my questions during office hours.............. Interestingly Alpha Bearings show the same big end for all 500 Bullets including 1953 and list the different big end for J2's with a steel con-rod. Mine has an alloy rod, so I may be worrying about nothing, all will become clear tomorrow, I'm sure.

[binary]

Hi John M I can see your dilemma. I am in the same spot right now. I am buying an Alpha roller bearing and just to make sure that I get every thing right I gave my crank to a local engineer that rebuilds British type motorcycle engines and cranks. I had him press apart the crank and give it back to me. This is what he did and I can see what I will want. You could go back to the place that is doing the work for you and perhaps do the same thing, get your crank pressed apart and take it home to measure the crank pin ect, to see what you really need. This may be the only way that you will know. Who knows what you will find perhaps some one in the past has machined and fitted a more modern crank pin that will need the Alpha bearing that you have at the moment the RE15. I see that the RE15 is the most expensive
and well made of the Alpha bearings. You may be able to machine and fit the more modern RE15 crank pin into your older fly wheels, especially if you are changing the con rod as well, it's just a thought. I think the same as Chris that if you have mistakenly ordered the wrong part and it remains unused and in its packaging then you would probably be given an exchange.

[Chris Tindal]

Those flywheels look quite different to my 59 500 ones.

[Tim NZ]

Those flywheels have been modified...


No idea what had been fitted to your motor, but the original crank pin and floating bush that I replaced in my 1953 JS Bullet is identical to the Indian made assembly.

[Mark M]

Those flywheels have been machined to remove some metal nearest to the crankpin and polished a little as well. The milling marks are very neat, probably not a garden shed job!

REgards, Mark

[Mark M]

John, I just thought of another identifying feature of your engine. You say the "Royal Enfield" plate is riveted on not the logo cast into the cover. This is correct for 1954 onwards Redditch 500s because from that time RE were supplying Indian with bikes (as the Woodsman for instance) and these had an Indian logo plate fitted.

REgards, Mark