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[ChrisD]

Well guys – again I must rebuild my 1996 535cc – after a total of ~16000kms. After a few hundred kms from the last work of trouble-free riding, cruising at up to 4000rpm, I was idling in a traffic queue, in neutral, when there was a series of metal crunches and the engine stopped. Jammed and damned.

When I tried to remove the left side spark plug (it’s twin-plugged) it wouldn’t unscrew. That’s when I knew it was bad.

When I got the other plug out and eventually removed the left side one, I found it had a perfect imprint of a valve head in it. Since I cannot now copy the image tag to place here, please see my Chrisd200 account at photobucket (the Broken Valve library). Here I am trying IMGBB as suggested by Exile.

.

The view through the plughole showed a bent valve lying on some unfamiliar texted aluminium, perhaps the inside the piston, which could be much more expensive.




Time for a rebuild, methinks.

NB: there was no warning to this break. NB too; This valve and the collets were the only indian parts remaining in the motor (apart from the flywheels). Well, I guess the valve was due to fail soon, based on the distances I’ve heard others have trouble, so I guess I only have myself to blame. I’ll keep you posted on the progress.

Cheers, ChrisD

PS: I shall follow this up as I summon the courage to remove the head.

[ChrisD]

Ah well, taken the rockers off and discovered the cause of the valve drop. The Hitchcocks inlet alloy valve collar failed (PN 90126) see the attached picture! And I made sure I used it with the standard indian valves and VS420A springs, as the brochure says.




Haven’t taken off the head yet – that will show the real extent of the damage. The valve must be wedged in the barrel, jamming the motor, so likely the barrel has gone (its an 87mm alloy one so the sleeve cannot be replaced) and maybe the piston too.
BUT step one is to remove and throw away the other alloy valve collar. NOT a safe item to sell.


Cheers, ChrisD

[Tim NZ]

Alloy collars are fragile; any significant damage to the collar from a V/v spring compressor can lead to premature failure...


Mismatched or poorly seated retaining split collars can also lead to failure.

[Adrian]

I don't know how frequently our hosts read the forum, but it's worth an e-mail to them with the pictures. A

[ChrisD]

Update on dropped valve – it will be an expensive event. The valve is seriously bent – I doubt I could use it again! The piston is essentially destroyed by two deep grooves (although it is materially intact) and the 'text' I had seen through the plughole was chatter marks on the exhaust valve. The head is also seriously damaged – I don’t know if it can be welded up, I suspect not. I hope so because I’ve spent a lot flattening top and bottom, enlarging the inlet port with a sleeve and twin-plugging with the decompressor in the centre (you can see the 2mm hole between the two gouges). And the barrel also has a deep ding – I hope that can be saved because I’ve also spent a lot flattening it too and machining for viton o-rings around the pushrod tubes. That is a hitchcocks checked alloy barrel which has been opened to 87mm to accommodate the 535cc piston. And sleeved once already when the gudgeon circlip broke and gouged the barrel (you can just see the sleeving groove). So, all in all, a pair of valves, guides, head, piston and barrel. That’s going to cost a fortune because final landed prices in South Africa are 110% higher than the list prices because of courier (because the postal service will steal things), the duties, tax and customs and handling. Yes, the engine is coked up because I put a 40 pilot jet in instead of 25-30. It idled much better too afterwards – I were that pleased with it, but it didn't have enough ridin to clean up, what with the valve an'all!

This has been an unlucky bike, but thankfully I wasn’t riding in the fast lane or I’d have been thrown off when the motor jammed!

Cheers, ChrisD

PS: yes Adrian, I have dropped our hosts a line.

PPS: TimNZ there are no damage marks on the collar from a bad compressor and the collets were certainly correctly fitted.

PPS: does anyone think the severe damage to the piston and the bent valve might have led to damage to the new steel conrod or bearings?

[Bullet Whisperer]

Hi Chris, it's times like this I really wish I had the time and inclination to post pictures on here, because I have had far worse than that repaired, with no problems. If that is the only damage and all below the piston is well, that head and the piston would be taking a trip to my alloy welders, if it were one of mine. As for the barrel, perhaps it could be re sleeved and used again? Regards, Paul.

[Alan R]

Hello CHRIS D,
Yes, I'd agree entirely with Paul as I also have had similar problems in the past......Your hardest job will probably be ensuring that ALL the oil and carbon deposits are completely removed such that the Tig-Welder can then run beads of Aluminium ( a-looominum ?? ) onto the parent metal.....
Don't worry, in the past I've recovered a piston from a Penta Marine outboard motor whose 3 piston ring grooves had collapsed completely on one side....Some TiG welding followed by some Vertical Milling over a rotary table soon had the boat back in the water again...