Bonneville America Forums Forums Technical Forums General Tech Air box full of old gas / oil goo..

I changed out my stock 2004 air box with a 2002 unit that had the divider cut out of it. When I pulled the rubber tube off the drain I was surprised with a flood of old fuel oily nasty mix. The P.O. never turned the gas tap off, but I have for the last 3 months. Has this happened to anyone else, and were did it come from..... The drain tubes (two of them) had plugs in the ends of them. Is this the way they usually are? I can see that you wouldn't want air sucking in there, but what good are they if they are plugged? I found the whole ordeal very strange. In a previous post I asked about exploding air boxes, and someone said something about fuel in the air box exploding, but I didn't believe it could happen like that........ I am re thinking that now.

I suggest a hammer and some pod filters

KansasBob,

I second that !!

The freak is one of the best mod's you can invest in.

When I did the "Ghetto Freak" mod I noticed both drain plugs on my bike did not have plugs. Looking at the exploded parts diagram from the bikebandit site, it looks like they're supposed to come with plugs. I bought my bike new and have no reason to believe the dealer removed them. Maybe it depends on the year? It's a conundrum.

I had no evidence of fuel in the airbox I removed, but I've always turned my fuel tap off being an old Norton/Meriden owner.

Regards,

Tom

The thing is without the plugs the tubes provide a source of un filter air for your motor. The plugs in mine consisted of rubber vacuum port plugs stuck in the end of the tube round end first. It works ok I guess, but not anything they were designed for.

The oily/fuely yuk that collects in your airbox is normal, it's WHY you have drain tubes in it. It happens from many sources, collected moisture from the air, stray unburned/partially burned fuel vapours, oil vapour from the crankcase breather etc which all condenses in the bottom of the airbox.

The drain tubes come standard with "squirrel condoms" on them to stop unfiltered air entering the engine. If you're one of those people who can't help but tweak the throttle when you start it cold you're going to get backfires from the carbs. That will not only blow off the squirrel condoms, but potentially blow up your airbox too.

It's part of the maintenance schedule to take the plugs out of those 2 lines and drain/clean them out. Every year/4000 miles, per the manual.

KB,
In my factory service manual, Issue 3, 11-2002, that info you posted is on page 9.18 and refers to the Bonneville T100.
In the maintenance section on page 2.3, the very last item in the scheduled maintenance chart is Airbox hose - drain...

I only found this out myself when I first had the bike, twisted the throttle when starting it, heard a huge "bang", and watched the 2 squirrel condoms go bouncing down my driveway....
When I went to reinstall them the drain lines were all slimey and gooey, and I asked similar questions on here.

I am working out of issue 4, 10.2004, and the maint schedule on page 2.2 and 2.3 pretty much mirrors the one in the owners manual. The last two items in the list are renew fuel lines, and clean air injection.

You are correct that the note on draining the filter box is in regard to the standard models. The filter box removal for the TBA,SM bikes doesn't even acknowledge their existence or what should be done with them during the removal process. Says nothing about draining the box either. One thing is for sure....... I will be checking them fairly ofter now after draining out close to a half a cup of slug..... or should I say dribble it all over my clean scooter.

Yes, the drain hoses are supposed to be plugged, this keeps the engine from pulling unfiltered air through them. It is part of the maintenance procedure to pull out the plugs and drain the hoses at every oil change. The airbox is designed to trap and condense oil vapors from the crankcase breather. Moisture often also collects with the oil, turning it to a gray or yellowish gunk with the consistency of year old jello.
Not to worry, just pop out the plugs once in a while and drain out the mess, then put them back in.
If you decide to eliminate the airbox, you should use a breather filter to replace this function and clean it frequently.