90 weight gear oil on air filter

I had a Honda mech tell me the other day that 90 weight gear oil (sticky stuff from $1 to $9, depending on brand name) is just a good as anything for foam air filter oil. Anyone heard that before?

He is a honda mechanic what do you expect.

There are trained at honda to think

As long as there dirt and gas in the oil its good

Back in the old days before all these new fangled contraptions and oils were used. We would just soak it 80 wt gearbox oil wring it out real good and let drip dry a day or so.

But thats when men was men and bikes were 340 lbs :)


I would only do it as a last ditch thing, meaning the shops are closed you are leaving at 3 am to go riding and thats all ya got.

LOL....that's funny..... He knew I had a 426, so he was probably trying to sabotage my Yamaha.

Ive done that for years there is nothing wrong with using gear oil all it is supposed to do is help trap small floating particles in the air. There is virtually no difference between Gear oil and air filter oil, same viscosity and does the same job. Ive done it on my 2 smokes and do it to this day on my 426.


Is is as sticky/tacky as filter oil?

Does it hold up (stay sticky) after sitting in the air box for a week or two?

Thanks JED

Another question: I noticed at the auto parts store there was several different brands and weights. Anywhere from 15w85 15w90, etc. Is there a difference? I should get the highest number (90 wgt) if I want to try, right?


If I'm not mistaken, the filter oils like the Maxima FFT has a solvent that slowly dries off and leaves the filter sticky. This might get the sticky oil spread out before the solvent dissipates and is better than plain gear oil catching those cylinder eating dirt particles. Sound good?

How can he stand the smell?

Try NO-TOIL, I did and will never go back! It is quick, easy and cleans up quicker than anything! You never hear anything bad about it. It sets up super-tacky and is cheap. It is all we use on any of our bikes

Personally I'm sticking with filter oil. The stuff I use is in a spray can and after you spray it the stuff slowly gets tackier. After about 2 minutes it's super tacky and you can grab the filter with your hand and when you let go you have strings of oil to your fingers, kinda like when you try to peel chewing gum from something. I personally don't trust gear oil to not run out of the filter and I'm not convinced it's any better at catching dirt than filter oil (which after all was designed to catch dirt). I had a pour bottle of the stuff and it was just as tacky but more of a PITA to apply (the spray stuff is more liquid and easy to spread immediately after you spray it on so it's easy to cover the filter without over saturating it and having to wring it out).

As for no toil, what I've read on here gives me the impression that some people swear by it and some people have found that fine dust gets by the filter when using it. Since I'm in a sometimes very dusty area I'm going to avoid it.

I have been using Bel-Ray filter oil since 1976 and I really swear by it. No dust found beyond the filter or in the carb boot yet. :)


I second the Bel Ray. I have been using it for years and have yet to find dust in my air boot. I have tried several others and have not found one that performs better. It's inexpensive, super tacky and does not drip off. With a 6k bike I'm not about to take my chances with gear oil when a quart of Bel Ray costs only about 5 bucks.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now