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[Bullet Whisperer]

Here's one to ponder, my 500 Indian Bullet from the mid nineties is used as a general knock about, getting plenty of stick and only basic attention. Last weekend, on Saturday, I used this machine two up for a run of nearly 100 miles with the Interceptor Rally,this year based at Llandovery. It rained a lot, but the bike gave no trouble on this run. On the Sunday, a much shorter run of about 15 miles took place and again the Bullet attended two up. This time, the pace was a little slower and at one point near our destination, there was a long, steep haul uphill for half a mile or more, followed by an even steeper descent. I abandoned my usual riding style and let her chug and labour up the hill in 3rd and 4th gears. All was fine until we crested the hill and started downwards. Pretty soon, on the downhill run, there was a terrible noise and I thought my silencer was coming of, there were metallic noises to back this assumption up, but looking down showed the silencer was still there and in one piece. I gave her some light throttle and nursed her for the next mile or so to our destination, where I stopped the engine and pressed the kickstart, to firstly get that noise again and no compression, followed by compression again. I left it a tdc compression and we went for a cuppa and a chat. On my return to the bike about half an hour later, it started up fine and we travelled homeward alone and more rapidly, with no sign of trouble all the way. My theory is this - labouring up the hill made the top end hotter than usual, but everything expanded pretty much together. Going down the other side promoted rapid cooling of the exhaust valve seat, while the rest of the head etc remained pretty hot for longer and this 'window' was all the exhaust valve seat needed to momentarily work loose and possibly tilt a little, preventing the valve from closing fully for a moment. Stopping the engine at tdc with compression evident and the valves shut then allowed everything to cool down together, allowing the engine to start and run as normal a short while after the event. Make of this what you will, but I think I will avoid 'plodding' and 'lugging' altogether from now on ! Cheers, Paul.

[vince]

Hi, My iron head clipper used to do this on a regular basis when climbing a long hill, First time I thought it had seized but the sound was wrong just an abrupt loss of power and a backfire followed by no compression, then the compression returned and away you go. It was nothing more than a sticking exhaust valve. With the guide reamed out the symptom never returned.

[Scalyback]

Oh my goodness!

This is exactly what Tornado does at the moment. suddenly stops with no compression, where I have to guess TDC, then with the throttle open a little, kick hard. Always works

The other symptom is the explosion through the carb, which blows the carb off the engine.



Tornado is going in for a right seeing to, so should not happen again.

[Nettshubby]

The older Indian bikes were known for the exhaust valve guide to come loose. Happened on my new '92. I fitted a new bronze guide from our hosts, i think it was a little oversize, but can't remember by how much.

[Chris Tindal]

Paul, just out of interest and off topic, what is your cruising speed on the bullet and has it the original factory bearings? I too have a 90's 500 engine that gets plenty of welly and minimal maintenance. I got it as a doner to resurrect a basket case 1953 350 bullet and love it to bits, but do wonder how long it will last as it's still original factory spec inside. I cruise at 55-60 with a 389 Amal and open pipe and it always seems happy.

[wilf]

It seems I am not alone. Back last summer, after a 60 mile ride I heard the most frightening roar from my iron barrel bullet, coupled with what sounded like the silencer being dragged along behind me. I was going up a gradual, but not steep climb in top gear, probably doing about 45mph. I closed the throttle a bit and looked for somewhere safe to stop, when it occured to me that there had been no loss of power. After a few hundred yards the noise abated and I rode the remaining ten miles or so home at a gentle pace with fingers tightly crossed. The bike has run fine ever since.

[Tim NZ]

Hanging onto a higher gear with wide throttle setting will see ex temps rise and cooling air flow reduced.


Relative air density effects F/A mixture a lot; ever notice that your bike seems to go so much better on the crisp cool winter evenings?


Ever wonder why it is only the exhaust push-rod that bends? Over heated ex port transfers heat into the ex rocker block that will cook-off the oil and seize the shaft in the block. Even momentarily and the compression disappears, then usually the Valve head and piston crown make contact, push rod bends, valve is bent too. The sound is much alike as when the ex v/v seat drops loose...


When the valve seat drops it will typically kant and does not fully return to its original seated depth upon cooling, thus tappet clearance will be greater