As per the title, has anyone seen black spots on K&N cone filters as fitted to the carbs on the Darmah. I doubt it's an oil mist from the engine as both front and rear filters show them. One possibility I'm thinking of is mould perhaps? Pics taken after cleaning them.
Yep, stored in a dry garage that is prone to condensation especially in the winter months. When the bike isn't used either. I suppose the follow up question is, will it have any effect on the efficiency/air flow of the filter?
A couple of my bikes have cone filters fitted and get the same black marks (mould) but they still work absolutely fine, I’ve had no problems whatsoever.
That's what you'd suspect & what I was thinking especially as there was a lot more on them before I cleaned & took the photos. I'm not sure there is any difference between the red & grey filters as they are both cotton gauze. The cleaning kit I used has a cannister of red oil which I'll use before refitting them. Darn it.... the bike has been a little tetchy starting recently and it seemed to me to point to the carbs and them being over rich. And I suppose I was just scrabbling about looking for evidence to back this up....
If you’ve cleaned them then any black marks left are just staining as that black mould tends to leave stains behind.
There are two types of K & N these days. K&N® HIGH-FLOW AIR FILTERS™ that use pink oil, and K&N® DRYFLOW® that don't. No idea if oiling a dryflow would be a mistake or not (if thats what you have?) https://www.knfilters.co.uk/cleaning
I'm pretty sure it's High Flow as per the specific product web page. And although it does state the air filter colour is red the picture shows it in grey along side a sachet of red oil.... I must admit I find the K&N web site a real pain to find the information you want. https://www.knfilters.co.uk/ru-2690-universal-clamp-on-air-filter
Using a rag dab a small amount of bleach on one of the black marks..leave for a hr or so, if it disappears then its prob mold
I must admit this was my first thought... the rhs alternator cover does have a weep into the drive chain area where it can get wet with oil. However I'm not sure it'd coat the rear filter as this is quite hidden by the rear mudguard plus there's not much overspray anywhere else. Well I have been careful with a couple of small spots and it does look like it is mould. And I'll be doubly careful and give them a swill before refitting.
