HELP: White smoke from chaincase/alternator and air filter.

I'm new to Norton's. I just purchased a '72 750 Commando Roadster that's been restored. The guy I bought it from put in a new electric ignition but it's still hard to start (doesn't help that I'm a litle guy). However, when I first got it back home and started it up I noticed a significant amount of white smoke coming from the chaincase where the alternator is located.

At first I wasn't concerned as I thought it was just oil burning off the muffler or chaincase from the ride home. I rode it around the block a couple of times and it was running ok. I got back home and shut it off and then restarted it after it cooled off and the white smoke seemed worse. I noticed it stopped smoking after it ran for about 10-15 mins.

The ignition was in the Ignition & Lights position. But when I switched it to the Ignition only position it killed the engine. Is that normal?

I toggled the key from position to position and when I did this a big puff of white smoke came from where the air filter is located. When it did this is made a "swooshing" sound. That made me worry. It was enough smoke that I thought something was on fire.

Since then I've started it and ran if for a few minutes. I've noticed the lights getting really dim and the brake light was so dim you couldn't see it at night. I checked it the next morning and the battery was completely dead. Now it won't fire.

Any ideas on whats going on? What should I do?

Some electronic ignitions spark when you switch them on and off causing the odd pop or two. The white smoke from the primary? you're going to have to remove the outer case and have a look.

Cash

Cash,
The initial smoke came from the primary chaincase, where the alternator is.
I'll dig into it and see what I can find. Thanks.

Re: HELP: White smoke from chaincase/alternator and air filt

tumtum said:

I noticed a significant amount of white smoke coming from the chaincase where the alternator is located.

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Where exactly was this smoke coming out of the chaincase?

tumtum said:

The ignition was in the Ignition & Lights position. But when I switched it to the Ignition only position it killed the engine. Is that normal?

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No, that certainly isn't normal, and with the lights switched off, the ignition should run slightly better? So I recommend you give the wiring a good check-over, especially the ignition and charging circuits?

tumtum said:

Since then I've started it and ran if for a few minutes. I've noticed the lights getting really dim and the brake light was so dim you couldn't see it at night. I checked it the next morning and the battery was completely dead. Now it won't fire.

Any ideas on whats going on? What should I do?

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The charging system certainly doesn't seem to be charging the battery, and electronic ignitions don't like low voltage, so I suggest that you re-charge the battery and check the charging system.

Use the info here to help you if you don't have a copy of the workshop manual yet: http://rocbo.lautre.net/technique/norto ... p/004.html

Where exactly was this smoke coming out of the chaincase?

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Coming from the front of the chaincase around the seals.

No, that certainly isn't normal, and with the lights switched off, the ignition should run slightly better? So I recommend you give the wiring a good check-over, especially the ignition and charging circuits?

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Not even sure I was able to start it in the Ignition only position.

The charging system certainly doesn't seem to be charging the battery, and electronic ignitions don't like low voltage, so I suggest that you re-charge the battery and check the charging system.

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Charging it as I type.
Will check it once it's fully charged.

Is it possible that the alternator fried and then the smoke from the air filter area was from the Sparx black box frying?

tumtum said:

Coming from the front of the chaincase around the seals.

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I can't quite understand how smoke could get out of the chaincase at that position, unless the gasket/s aren't sealing properly?

tumtum said:

Not even sure I was able to start it in the Ignition only position.

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In which case, either the switch is faulty, or the switch wiring is? Or something isn't connected correctly?

tumtum said:

Is it possible that the alternator fried and then the smoke from the air filter area was from the Sparx black box frying?

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I can only suggest you re-check it all once the battery is charged?

But I would strongly suggest you remove the chaincase cover and check the alternator first, and see if you can discover exactly where that smoke is actually coming from?

I can't quite understand how smoke could get out of the chaincase at that position, unless the gasket/s aren't sealing properly?

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One thing the seller told me was the chaincase gasket is in need of replacement.

Thanks for your help.
Will post an update later.

I'd also check the main drive side oil seal?

As that smoke could possibly be crankcase fumes that are getting past a blown seal and into the primary case?

I suggest you pull the outer primary. Measure the clearance around the rotor with a non magnetic feeler gauge. You should have 0.008-0.010" clearance all the way around. If you have rotor to stator contact, you will see smoke and maybe worse.

The ignition was in the Ignition & Lights position. But when I switched it to the Ignition only position it killed the engine. Is that normal?

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This could be a bad contact on the ignition switch. You can carefully take it apart and clean it, or replace it .