Tim

That's right, four cylinder and not terribly popular. Thanks for the advice. I did actually do that, feeling slightly pleased with myself. But I just think I skimped where I shouldn't have done, like I say K&N don't make an air filter so I've gone original, may have to make my own air box cover if it doesn't come with one. Heaven knows how I'll do it though.

Thank You, You could have a point there, I have a very distant memory of someone saying something similar. VERY distant. Spoke to Fowlers, very obliging but didn't know so I've ordered a filter with an extra helping of hope. K&N only make replacement oil filters for this one, a good call nonetheless. Cheers

Thank you, all Yes ok the bollocking can start and will be dutifully accepted. Umm I might not not have done any rejetting and I suppose I was in denial that it would need doing. Also I read that with K&Ns no rejetting was necessary, and hoped that would extend to any cone filter. The damage the web can do to the naive. I will bow my head in shame and visit a professional. The reason I don't have the original air filter is simply because the filter box is missing the lid and I can't find one for sale anywhere. I think I should keep looking for one. Thank you for the common sense it is gratefully received.

Good evening New member here and I'm already looking for help. Are all after market air filters the same as far as breathing goes, or is there a significant difference depending on brand and/or quality. Now the question is out of the way I'll set the scene for those who are struggling to sleep. I have a GSX400f which I'm slowly "restoring". I've put cone air filters on it which I picked up from Amazon for, admittedly, not a lot. I have stripped and cleaned the carbs, pushing nylon bristles through the pilot jets to clear them. The exhaust is a very elderly N-eta Today I rode it on the road for the first time and it wasn't anywhere near as sprightly as the one I owned thirty odd years ago. The poor thing runs very flat, hardly gets up a hill and whilst it revs fine on the driveway, as soon as there is any resistance like going up a hill, it can't do more than 40mph. My thoughts are that it is cheap air filters but I wanted to iron the idea out before parting with quite a chunk for Ram Air foam pods. All the best Tim