Smokey air filter

Tornado · Apr 10, 2020

During my recent first of season shakedown/lockdown run, I noticed what appeared to be light bit of smoke emanating from the K&N full size air filter. Only seen at idle, it would suck back into filter if I rev'd a bit. Had a few back fires when first starting, hope its not doing a smuldering burn. I think it might just be oil breather doing its thing, venting into the air cleaner box. I am running the MikesXS reed valve and it is sitting lower than output end, so maybe some sludge has builtup and aerosol misting up into filter box?

maylar · Apr 11, 2020

Hard to say. Possibly oil mist from the breather, check the oil level. Backfires could spew fuel vapors out of the carbs, I sometimes get a puff of smoke out the air filter when I shut my engine off.

Bernhard · Apr 11, 2020

K&N has its own air filter oil, it should be squeezed out before inserting. I would never vent any oil pipe into the air cleaner box on any engine if I have one I would put it into a separate clear bottle.

Tornado · Apr 11, 2020

My filter was last cleaned and oiled a year ago, so issue is not an over oiling of the filter. Engine oil was a little below max point, with a freshly drained sump. Might be thats still considered too much and is giving more aspiration into breather than usual. Note breather is as for mkii 850, up high on timing case where an electric leg would go.

Torontonian · Apr 11, 2020

Noted to above posts. When was the last time you changed the inlet valve seals ?

Tornado · Apr 11, 2020

Torontonian said:
Noted to above posts. When was the last time you changed the inlet valve seals ?

Last year as the right side pipe was giving puffs of blue when blipping throttle. Cured with fresh Kibblewhite Viton inlet seals and fresh springs all around...all done with head still on bike. No sign of that when I noticed the filter mist/smoke.

cash · Apr 12, 2020

It could be "stand off" and that's usually associated with the cam timing out or a very wild cam, and I don't think there's a Norton cam that wild. But could the vapour blow back through the filters?
Have you taken the timing chain off over winter?
Dave

baz · Apr 12, 2020

So does your breather come from the timing cover to the reed valve then to the air filter?
Or does it go to the oil tank?
And the oil tank breather to the air filter?

Tornado · Apr 12, 2020

Timing chain refreshed with a new AN one and tensioned to spec with the holding bracket from OldBrits.

Reed valve attached to short hose to timing cover pipe. The to standard breather hose to tank, which ends at tank neck, which has a pipe/hose to filter housing.
The amount of "smoke" is really just a wisp that lingers in still air. I saw it in bright sunlight. Could see it suck back into filter if I turned revs up above idle. Repeatable wisps appeared when back at idle.
Oil was freshly changed, so not likely water vapours from winter storage.

maylar · Apr 12, 2020

Might be a bit precarious to stick your puss down there while idling, but a sniff should tell if it's oil or fuel.

Tornado · Apr 12, 2020

maylar said:
Might be a bit precarious to stick your puss down there while idling, but a sniff should tell if it's oil or fuel.

No need to do so while moving...I've only seen it while idling on the CS....poking about with the idle/mixture screws etc. Didn't give it a sniff though.

Will need a few days to revisit the card idle air mix passageways to sort out the left side needing less than 1/3 of a turn from fully closed to get any engine affect. Was spraying fine on the bench but might have picked up some debris since fitting. Other than that, she's running pretty nice once off idle, good power pick up.

Craig · Apr 12, 2020

I fill oil tank just a tad over halfway between the marks ...

Smokey air filter

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