R100RS air tubes

[mrocket49]

I bought a 1981 R100RS that had the air tubes from the carbs to the air filter removed and plugged. I was thinking of re-installing them since that is what came on the bike. I was wondering if there is any reason not to do this, such as loss of power.

[88bmwJeff]

Removing the pulse air system is a common modification. It is recommended by some. It has been reported that the added air increases the temp. on the heads, and does little to nothing in helping emissions. For more information read Snowbum's article.

http://home.jps.net/~snowbum/pulseair.htm

[jmerlino]

Leave them off. It looks better. :brow

[lkchris]

I bought a 1981 R100RS that had the air tubes from the carbs to the air filter removed and plugged. I was thinking of re-installing them since that is what came on the bike. I was wondering if there is any reason not to do this, such as loss of power.


If this is what you REALLY mean, of course you should connect carbs to air filter. Take the plugs out too, so your bike will run!

If instead you mean the "pipes" from airbox to cylinder head--the air injestion system--leave them off.

[mrocket49]

It sounds like the previous owner of my bike did the right thing by removing the air tubes. That website link explained it well also. Thanks

[jmerlino]

If this is what you REALLY mean, of course you should connect carbs to air filter. Take the plugs out too, so your bike will run!
I don't think he was talking about the intake tube. :laugh I think he was talking about the vacuum port tubes that run back inside the airbox. My bike had the pipes to the heads taken off already, but the PO left the carb tubes in place. I ditched 'em and put caps on the vacuum ports. Much neater look.

[barryg]

Check the microfiche on the pulse air system on the dealer sites. U will see that the pulse air components take up a good portion of the interior of the air box. If it's still there, It wouldn't hurt to remove it as well, since it now serves no purpose.

[RandyB]

As long as he's in there, what's the consensus on removing the oil recirculation tubes in the airbox? The ones that redirect vaporized oil into the carbs. I've seen people do this and it stops the drips and doesn't seem to hurt anything.

[jmerlino]

As long as he's in there, what's the consensus on removing the oil recirculation tubes in the airbox? The ones that redirect vaporized oil into the carbs. I've seen people do this and it stops the drips and doesn't seem to hurt anything.

Where does the oil go, then? Or doesn't it need somewhere to go?

[RandyB]

There's a little vent in the rear of the box, but there didn't seem to be enough trapped in there to matter. Either it drains out or it gets vaporized and sucked in right away.

[lkchris]

There's a little vent in the rear of the box, but there didn't seem to be enough trapped in there to matter. Either it drains out or it gets vaporized and sucked in right away.

This is a VERY important part.

It's of course the air filter water drain, and is a suboptimal design since it's on the clean side of the filter.

Be sure yours is present and flexible enough to shut itself when the engine's running, or otherwise you have a dirt entry problem.

Most airbox designs are updraft.

[mrocket49]

I checked inside the airbox and the breather hoses from the engine cover are there. The air-pulse hoses and valves were removed, I have them in a box. I checked that small flexible drain in the bottom on the airbox and it seems to be fine. There is alittle bit of dried oil/goop in the bottom corner of the airbox so when it gets a little warmer, I'll remove the box and clean it up.
I can't wait for warmer weather! I also just installed K75S handlebars to make it a little more comfortable. I was surprised that I didn't have to replace any cables as some of the posts had sugested. The bike does have stainless brake lines so maybe they were a little longer than the stock ones.
Thanks for all your help.

[28796]

Where in northern Ct.? I'm over outside of Danielson.

[mrocket49]

Suffield. You've got some nice riding out your way. We sometimes head out that way on mid-week rides. We take rte.198 east to Woodstock. Lots of nice scenery. There's a country store out there that serves sandwiches that we stop at for a meal or ice cream in the summer.

[RandyB]

This is a VERY important part.

On the list to be replaced along with every other rubber and plastic piece.

[beemerPhil]

Lots of bikes used air injection in the late 70's/early 80's, just as lots of cars did, to meet emissions regs, short term, until engineering could catch up with the new specs.
The tubes have absolutely no effect on mileage or performance. They ARE original equipment on these bikes, but unless you're a VERY anal collector, they're not significant at all. The only 'side effect' is a very minor exhaust rattle(a really small backfire, actually) that is only audible from another bike behind you- and an increased tendancy to blue the header pipes, caused by the 'afterburn' of unused fuel in the header pipe downstream from the injection port.
If you've ridden your airhead much, the headers are already blued- valve and heads are upstream of the injected air, so they won't even know the difference. I wasn't even aware of the slight backfire effect until I swapped rides with a buddy- it bothered him, but really wasn't anything- ever ridden with a friend on a hardly ableson? It's NOTHING like that!
I wouldn't give it another thought, unless you're concientious about emissions- then, by all means, hook em up, it's free!

Ride safe- someone would miss you, and you'd $#@&-up your bike!