Hello, I have a 2019 SG I purchased used 4 months ago & It's almost dialed in. My ideal setup is stock with slip-ons and a high flow air cleaner as well as an external breather. The bike came with a Roland Sands air cleaner (Venturi) but I like the stock air cleaner look with different trim so I bought the K&N HD 1717 high flow filter and stock air cleaner.

After installing the external air breather hoses & filter along with the new K&N filter I went test riding I did about 100+ miles to make sure the bikes computer does its thing.I've heard the M8's adjust and they do not need a tune for air cleaner and slip-ons and that has been my experience. I had this bike dyno'd and the curve was fantastic at stock tune. I've been experimenting with different air filters too a little bit. No tune was necessary. Back to the story....So after the bike normalized after the 100+ miles I could not have been happier. Everything was firing perfect, from the sound and feel...I was also getting really good MPG. Watching the numbers. The bike felt great and it was giving me great power in every single gear. I thought I discovered gold. Here's the punchline.....the stock hose that attaches to the breather bolts and goes back into the engine was removed. But, I forgot something, can you guess? I did not plug the filter hose hole back up. Small hole for the tube.

So, I found a plastic piece at the plumbing store to plug the hole up, put everything back on and test rode again 100+ miles..........now I'm sad. Better than stock, but after feeling what this engine is capable of......
It's a small hole. But that small hole let in just a bit more air made a difference. So, my question is.....has anyone jimmy rigged their air cleaner to get more air than the filter will provide? I realize it may be a dumb question but I couldn't find anything on the internet. I just bought a special bolt that has a very fine metal filter built right into it. I can post a pic if anyone is interested. Was thinking of drilling a hole in the K&N filter and putting this filtered bolt in to get back the performance that I had yesterday.

Any insight would be greatly appreciated. I'm green. Thank you

 

It's all in your head. Having the small hole open, all it did was allow unfiltered air in. The amount of air your K&N is capable of flowing far exceeds what your stock engine can consume.

 

thank you for your reply… I’ve definitely considered that. The exhaust note was certainly was a little different and maybe it’s because of how I was test riding it but it was pretty exciting 😆

I really appreciate someone with a little more experience weighing in here so thank you.

 

Hi, yes please post a picture of the bolt with the filter.

The M8 have the head/breather bolts with rubber hose directed into the throttle body to vent the heads/engine into the intake. These hoses vent and as they do, minute amouts of oil mist is sucked into the engine.
EPA requirement. Many owners have installed a cleean air external air filter system. Some are a catch can, some are a small washable filter to catch the mist oil. Some kits are made for less than $75 and other systems are up to $500 + ( Trask).
What is refered to as clean air systems reduce the temperature of the air flow into the engine since the hot head gas is diverted externally.

Good Day~

 

Yes, I have an external breather with a filter. After reading some more I’m just sticking to the K&N filter how it is. Appreciate the input. Thank you for your reply.