Need for this product
The need for using a foam air filter oil is present in motorcycle owners like myself. Cleaning and reapplication is very important in optimising the efficiency of the air filter and in turn the performance of the engine. Motorcycle air filters are often prone to gather dust and other particles picked up whilst on the road or even when stationary. A dirty filter can lead to muck and dust getting into the engine, which is certainly something you want to avoid if you want your engine to last!
Choosing the right products for the job is obviously very important. This can save on both time and effort, and overall will produce better and more efficient results. I am all for maintaining the performance and longevity of both my air filter and engine, so I use the best products I see available to me.
Castrol Foam Air Filter Oil
Choosing the best quality you can afford is always wise, and at around £5 for a 400ml canister it is well worth the outlay. Cleaning your motorcycle air filter should always be an ongoing duty through daily use, but if you are a Summer rider like myself I prefer to carry out this task just before I start the engine for the first time in the summer. Air filters can collect dust during daily riding, but I find that whilst unused the filters are real dust and grime magnets. A dirty air filter can lead to poor engine performance as it can be starved of the correct air flow, meaning inefficient performance. The Castrol Foam Air Filter Oil is the most effective oil I have used to date, though i have only used very cheap brands in the past which i have had in my garage for many years, so I suppose this is the first real product I have tried if I am honest. The instructions are on the canister, and outline the application process and also the things to be careful of (such as ensuring you don't get it on your clothes). The oil itself isn't overly thick, so it is quite simple to apply, but it also lasts a good amount of time before needing reapplying. I carry out this process once before the summer riding season starts, and if I have ridden a lot during the summer I will do it again halfway through the season. If you are a regular rider you would have to make your own mind up with regards to how often you reapply it, though I suspect this would largely depend upon the road conditions and surfaces you encounter.
Application process
This Castrol Foam Air Filter oil comes in a handy tin canister and is of a reasonable size. The white cap simply pops off and the oil can then easily be poured out into an old dish or washing up bowl. The filter should always be cleaned first, but as this is the oil application this product won't do that task. Once you have your clean filter you simply pour enough filter oil into the bowl and then soak the filter in the bowl. The oil is a very right and bright red colour, so it is easy to identify if you happen to accidentally spill any. It is wise to wear old clothes and put a protective sheet down when doing this, as oil is a real pain to get out of clothing!
Once you have soaked the filter in the oil you simply have to squeeze out any excess oil which would otherwise drip. The oil filter should then be left for a while to allow it to dry before re-fitting it to your motorcycle.
Final thoughts
I wouldn't say the application process is particularly difficult, in fact I find it quite straightforward. It can be a little bit messy, but this isn't a negative point of Castrol Foam Air Filter Oil, as this would be the case with any oil really. I think the price is very reasonable, especially considering you don't need to apply it too often. If you clean the filter properly in the first place, when you squeeze the excess oil out of the filter you can always reuse this in the future, so there is never any waste.
Oil your filter for max performance! 
