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[stuarturq]

My Bullet 500 is making an odd swishing sound when under load and has done so since I bought it last November. The sound is more pronounced when warmed up - a bit like a loose nut vibrating on a mudguard, though not so obvious, or like loose clutch wheel (primary drive checked and all fine). The bike (2004) has only covered 1700 miles. I've fitted a new Hitchcocks 5 plate clutch to cure previously grunchy box (now great), new oils etc. I have a friend who says his Enfield makes the same sound, another who's doesn't. It's not an alarming sound but I cannot trace it. Tappets all correct, primary drive all OK, chain(s) tension checked, gearbox and engine oil changed with no evidence of failing bearings or unusual wear etc. Engine sounds lovely, no smoking or other ailments. Sound becomes less pronounced when coasting in neutral. Any ideas?

[Les]

Have you tried turning the rear wheel with the bike on its stand, is the chain guard touching the chain or vibrating about

[Scalyback]

If the bike doesn't want you to find the rattle, then you won't.



Mine is exactly the same. two mechanics, a partial strip down, still nobody knows!

[MickB]

Me too, been like that from new. Now done 6500kms with no problems. Harley dealer said it was quite common and nothing to worry about. Sounds even worse when the fuel tank's getting low, bit like a ball bearing spinning around in a tin can. Oh the joys of owning an Enfield...

[stuarturq]

Mick B - that's an even better description!!! I took a friends 1951 Triumph Trophy (I'm sorting for him) for a 3 hour run today and it makes the same sound when it's up to running temp. I've had many, many classics throughout my long years of motorcycling and have never come across this odd sound. Something must be making it? Timing gears was another theory I'd heard. But a ball bearing whizzing round in a tin can is bang on. (No chains rubbing either guys and nowt external is loose). It's baffling. Winter strip-down?

[Frank]

Clutch hub bearing surface worn perhaps? Mine went and I can relate to a swishing sound, worse under load. Plenty of ball bearings there to rattle about. Impossible to see without stripping the clutch down but you might find tell tale glitter in the primary oil.

[stuarturq]

Thanks Frank. No glitter or debris in the oil, but will have a look at the bearing. I'll be surprised if this is the case on such a low mileage machine. Mind you anything's possible given its origin.

[Frank]

Stuart, mine was in perfect condition when I reassembled the clutch. Within 10 miles it had been destroyed. One of reasons was that I had fitted the rubber faced chain tensioner bolt which pulled the primary chain out of line and in turn pulled the clutch out of line, or at least put uneven tension on it. I also reckoned it hadn't got sufficient lubrication. You live and learn but it can go from perfection to destruction very quickly.

[stuarturq]

Gave this a little more thought Frank and when in drive the clutch ball bearing is locked/stationery. It will only spin when selecting gear and clutch is disengaged. Noise ONLY appears in drive (all gears)so I now suspect noise is coming from a gearbox roller bearing, both of which are continuously in motion EXCEPT when clutch is engaged (noise falls away).

[p]

I would try putting a pint or so extra of engine oil in primary case (just to test!) and running a few miles - would certainly deaden/change the noise if it was coming from there!

Oh, have a look at the "3rd"(the bigger one) bearing in back wheel, wear here can cause hub to rub inside of cush drive area...... may make a noise under different loads??