1986 En450 Air Cleaner Grommet

[meyotch]

Quick question. I'm new to this bike, but am an experienced rider and adequate mechanic.

I was cleaning the air filters and noticed that there is a hole in the front (carburetor side) of the air cleaner box. On my bike the hole is incompletely plugged with a rubber grommet. There is a hole in the grommet large enough to stick one of my skinny fingers in easily.

Now, my question. What's going on here? This hole is past the air cleaners and allows a lot of unfiltered air right into the air box. I've checked the parts fiche, but it's unclear if there is supposed to be a filter or some other barrier contained within this grommet.

Does anyone have experience with this? It seems to defeat the purpose of having air filters.

[wanchesenative]

Do you still have the emissions junk on the top of your engine. There is a hose that goes from the emissions to the air box. If that junk is gone, just plug it off.

[meyotch]

Ahh, okay, the hose to the emission control unit wasn't obvious from the parts fiche. Apparently those parts *have* been removed now that I squint more carefully. I just happen to have a loverly rubber stopper that fits nicely in there.

Problem solved.

Now I need to figure out how to fix the slight back-fire I get when easing off the throttle at speed while in gear... This is my first older bike where it is relatively easy to mess with the fuel system, so I have some learning to do.

Thanks for the tip.

M

[violetsimmons]

Hello..
I am newbie here and really sorry if asked something not related to the topic. I am new to the profession of repairing so don't know the purpose of grommet. Can you please help me out with it.
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Have a look at grommets desk .

[Jet⚡Black]

Carburetor wise three things could cause popping:

1. Dirty or poorly adjusted idle jet on the affected side. 2-1/2 turns out is a good starting point for pilot jets.

2. Carburetors are not synchronized.

3. Vacuum leak on the affected side.

Non carburetor: Exhaust leak, emissions stuff clogged up.

You said the emissions hoses etc were off; make sure they did the job right, the block offs on top of the head cover need to be air tight and the reed valves removed. The crank case breather filtered, that grommet plugged, and a carb vacuum plugged on one side or t-ed.

I'm leaning towards the popping to being an emissions or a vacuum issue, quite possibly corking that grommet hole will fix it.

[Jet⚡Black]

Violet, the grommet on the air box was designed to have a hose run from the air box to the breather hole on top of the engine case, (the round circular thing with a bolt in the middle and an offset hose port that looks hinged) It is a piece of emissions design, to make the engine re-breathe engine waste air, instead of fresh air. In other words government required junk that chokes your engine like smoke does lungs.