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[Alasdair S]

Thanks all for your fast and knowledgeable responses - first time posting on this forum and what a great resource it is. Interesting thoughts re the sticky valve train - as part of the work I did, I used a dremel and some wet and dry to clean up some of the appalling tolerances in the intake manifold (there was a lip about 6mm deep inside the intake spigot!). I was very methodical, but I'm wondering if maybe I wasn't careful enough and some aluminium swarf got in and is causing the valve to stick in the guide. Shall check and clean. I'll also refit the original rockers and see if that has any effect.

Simon - many thanks for the final summary of your mystery clank - I'm tempted to think it might be the same problem. I haven't had chance to check the pump spindle/worm drive yet (tomorrow morning's job) but seems likely as it's standard fitment and probably hasn't had the easiest life. Will let you know. Thanks also Scalyback for the video - your clank sounds a little more frequent than mine but of a similar nature, I'll be sure to check for your problem.

Cheers Adrian - I'll check the cams for movement and the inside of the timing cover for witness marks when I have it off tomorrow. And thanks Tim - shall have a look. I'll keep you all posted! That clanking gremlin won't know what hit it. All the very best folks, A.

[simon]

The reason I think mine is the right answer is that your noise like mine is intermittent without any perceivable rhythm. All the other causes would have some sort of engine speed relation even as a syncopated beat. Also if I am correct you noise doesn't effect the idle at all. The bike ticks over merrily with an even beat despite the terrible clanking. A slipping worm drive would have this random patten and wouldn't effect the running of the bike. Finally after our machines mine is circa 1992 they changed the spring weight on the oil pump cylinder to springs which I believe was due to this problem.

[Alasdair S]

Hi Simon. You're absolutely correct - the noise is totally out of sync with the engine's speed, and there's no impact on the idle whatsoever, the bike just ticks away quite happily. The clank is also worst at idle, as far as I can tell - in fact initially, I think it disappeared altogether at higher revs (hard to tell, though, because the engine noise increases and partially covers it). I guess the power delivery is going to be most intermittent at idle, and it's probably the acceleration and deceleration of the worm gear which is likely to make it slip. I shall strip it out and put up some photos tomorrow for inspection. What's the significance of the change from a spring weight to springs? Is it worth making this change? I hadn't heard of this before. Thanks for your help anyway mate - much appreciated. A

[simon]

Yes you should it's a recommended modification. The reason is that the only form of oil pressure relief valve in the Indian Bullets is the pump bodies actually lifting off the pump housing. If the springs are high pressure ones then the pressure is transferred to the drive. I seized my pump completed by installing a hi capacity pump and using straight 50 oil which resulted in the pump spindle (a brand new English made one) stripping completely. Using a multigrade sorted the problem along with a new spindle obviously.

[Alasdair S]

Ah I understand - so a lighter weight spring allows some movement of the pump in the housing and evens out pressure spikes? Sounds like it might be worth doing - would like to avoid stripping a new spindle if at all possible! I've been using Halford's 20W 50 vintage motor oil for the last few thousand km and it seems to have been ok so far, present troubles excepted. We shall see anyway - I'll chuck some photos of the pump components up tomorrow. Thanks for all your help mate - A.

[vince]

If you have fitted new rockers check that they are not to restrictive to oil flow, Had pump strip on start up of new racer and discovered that the rockers were not letting oil through, there should be no resistance to an oil gun pumping through, on these you couldnt pull the trigger! Light springs in pump are designed to lessen the load on the drive.

[Alasdair S]

Hi Vince - good thought, I'll definitely check that. Bought the new Samrats from our hosts here so can be relatively confident in quality, but worth a look nonetheless. I've heard of people machining out the oilways in their rockers to help with flow - anyone tried this? Apologies to everyone else for going quiet on you all over the weekend (was away on my stag do!). I got the oil pump apart on Friday and found a couple of things which could well be the cause of the tapping. Although the spindle teeth looked pretty much ok, the worm drive had a few chunks missing. This was from the very end of the worm, where the thread gets very thin - easy to see how it could break if this part was ever in sole contact with the pump spindle. That said, I'm not 100% sure if the case - it's hard to tell. Thoughts anyone? The other thing which made me a little suspicious was the pin on the rear end of the pump spindle - this was very sketchy looking, with several grooves worn into it along the length. It was also a terrible fit for the the plunger, which was free to rock by 15-20 degrees. So - got some pictures, which I'll show y'all tonight (need my home laptop to get them uploaded). In the meantime, waiting for an order to arrive from Mr H's Emporium of Bulletty Things, which will get me a new worm, spindle and the lighter springs as suggested by Simon. Time will tell...