Hitchcocks Forum

Hi all. Need some advice please. I've had this bike since 2008. It's a 2007 Classic e/start. It had done 17 miles when I bought it. The guy had all the mods done that he could think of - 535 forged piston, ally barrel, lightened valve gear, AMAL carb, Goldie exhaust etc. When I bought it, the sprag was bust, of course.

Took the bike into MOT/service. The guy there is a real RE enthusiast. We looked inside the primary drive cover and he was horrified that the crank was bent. It actually contacts the alternator and it's noisy when the cover's refitted and it's running. He thinks maybe the crank was bent through kick back during the first 17 miles.

I've done about 800 miles on the bike. It runs absolutely lovely and pulls like a train. Can you tell me this: Should I get the crank sorted as a matter of urgency? Will it fail on me? Can I just carry on and ignore this as just a feature of the bike? You'll appreciate that a new crank would be a major pain in the wallet for me.

Thanks for any advice.

It's not completely clear from your description but it could be the alternator rotor that is faulty, either out of true or otherwise mis-aligned. If the crank was bent you'd really feel it and the main bearings wouldn't last long, certainly not the 800 miles you have done!

REgards, Mark

Are you sure it's not just the stator that needs repositioning? You shouldn't run it with the stator and rotor in contact or it's new alternator time. I'd remove the alternator and get an indicator on the crank to check.

To back up what Mark M has already said, I remember working on a 350 Indian Bullet where the owner thought the big end was gone, but it turned out to be the crappy Indian alternator rotor was starting to come apart and one magnetic segment had moved out radially and was hitting the stator - it might well be worth looking in this area. Regards, Paul.

Well thanks for those replies which could be reassuring news. But if the alternator stator was out of true, would the misalignment look different? As far as I can remember, when I looked at the end of the crank as the other guy turned the engine over, there was a definite and visible run out. If the alternator was wrongly set up, wouldn't the misalignment be in a consistent place?
However - if you think a badly bent crank would have done for the main bearings, I have to say there's no rumble that I can detect. The noise from the primary drive case is definitely more of a rubbing sound.

Remove the rotor and watch the actual crank end to see if it is the crank or the rotor that's out of true. I, like the other guys would suspect the rotor.

And updating the alternator isn't a bad idea anyway. The Indian one is not particularly well made or powerful.

Before you suspect a bent crank have a read of this. My Bullet, same model as yours broke a primary chain riding along at 70kmph. The chain tangled in the case wrecking it and stopped the engine dead. When I finally got the broken chain and chaincase apart I ran the motor with just the starter and main sprocket, left the clutch etc off. I did this to see if the motor ran ok. Sure enough the shaft was moving up and down like it was bent and the main bearing was making a loud whirring noise. I knew I had to pull the motor down which I did. All it was was the crankshaft had twisted from stopping dead on one side while the right side must have shifted a smidgeon. I took it to an engineering place who pulled it apart, checked the conrod for straightness, which it was and re-aligned the 2 sides of the crankshaft. Not a job I would try myself but they only charged me $100 and now my shaft is straight as a die.