What the hell is this?

[timkil]

Greetings Airheads, I've got a carb gasket kit on the way. This is my first airhead, so I've been researching the carb teardown info in my book and on the web(Chris Harris in New Hampshire on youtube). I love the way he curses while he works. We have a lot in common. Anywhoo, The carbs on my 83 R80RT have an added feature I haven't seen any where else. Where the balancer screw should be plugging the orifice, there resides a hose which disappears under the rear edge of the top block cover right in front of the airbox on both sides. There is no screw in the balancer nipple. I can't tell if they are connected of if they have some other final destination. Any thoughts? The PO had ALL of his service done by a local independent BMW "specialist". I mean ALL, oil change, brakes etc. I found that the "specialist" had reused old rocker cover gaskets with a liberal use of silicone goop. This explains the long string of silicone snot I found on the oil filter and the hour and a half I spent cleaning the gasket surfaces when I checked the valve clearances. I can't figure out how to get some pictures in here so I hope my description will suffice. Are these hoses some sort of perpetual carb balancing on the fly? Sign me out as Confused.

[captmako]

I am certainly a newbie with Airheads, but I think those black hoses run to the 2 solenoids in the Shed Fuel System on
top of the motor. Most folks as I can ascertain prefer to remove the whole cracking system. I'm sure other more
learned and experienced wrenchers will chim-in. Just my .02 worth. Good luck, mate.

[Deleted User 62]

I think that hose would have originally been connected along with the other carb via a "T" fitting to the air box back when the bike had all it's emissions plumbing. If it is that one, the tube on the carb where they mount should have threads and can be plugged. You'll need to plug the hole in the air box as well.

[captmako]

My apologies, I removed all the junk from the air box and the shed fuel system. Got the 2 confused which at
my age is certainly possible and happens all too frequently. I defer to Tim. Thanks mate.

[timkil]

So I can rip this Shed Fuel system out? What does it do and what's the easiest way to get to it, top cover off? What size and thread screw is used for the nipple? Questions, questions

[ibjman]

I know I'll catch a LOT of guff from others about this.
I have an 82rs (+ 3 other motorcycles) with the identical exhaust air system installed.
I can see no advantage to removing it. The bike will not run any better or differently without it. It does not cost any fuel mileage or deter performance in any way. The only real justifiable complaint you might hear is that it creates some popping, backfire in the mufflers when slowing down at closed throttle (exactly what it's designed to do). It simply sweeps some additional oxidizing fresh air into the exhaust ports at the entrance to the exhaust pipes in order to more fully re burn the left over wasted hydrocarbons going out into the air we all live & breath. Do yourself, the other people in the world and especially the next owner of the machine a huge favor and leave the equipment on the bike that BMW designed to be there.
I recently acquired a California 1998 R1100RT that some previous owner had removed the evaporative emissions charcoal canister from and, of coarse, discarded all those parts. It cost me hundreds of dollars and weeks of work to obtain all the needed stuff to get the thing back to original condition.
You'll hear 100's of stories about the huge determents that are supposedly caused by modern emissions equipment on the bike. IMO, most of those people shouting about tearing stuff off the machine and throwing it away are simply butchers that have little understanding of the total machine and even less regard for themselves, their loved ones or there fellow man.
Leave the machine completely stock. You'll have a much better overall rider experience and maintain a far better resale value when you're ready to trade & move up.
If you want a machine with no such equipment, just by an older less technical machine.
Although it is likely that the average user will not ever see or realize the difference in performance, reliability and or drivability, every change made from the stock design will always have a downside equal to or greater than the "perceived" improvement in performance.
Regards, ibj...

[timkil]

No guff from me ibjman. So if you leave her as is, do you just yank the hoses to balance the carbs?

[khittner1]

Others will have additional info, but the critique of the supplementary air injection system that I've heard is that continued burning of whatever unburned fuel remains in the exhaust gasses generates additional heat in the cylinder head, particularly on the exhaust valve sides, accelerating valve wear, warping heads, particularly in the 1000cc machines that have less metal to distribute/dissipate heat from, etc., and whatever other parade of horribles can be imagined. I won't pretend to know much about the effectiveness of the system at reducing pollutants, but lacking any catalysis system, I'd assume that it's limited, hence, the K-bikes, oilheads, etc.

Konrad

[Chuey]

I know I'll catch a LOT of guff from others about this.


less regard for themselves, their loved ones or there fellow man.

Leave the machine completely stock. You'll have a much better overall rider experience and maintain a far better resale value when you're ready to trade & move up.
If you want a machine with no such equipment, just by an older less technical machine.
Although it is likely that the average user will not ever see or realize the difference in performance, reliability and or drivability, every change made from the stock design will always have a downside equal to or greater than the "perceived" improvement in performance.
Regards, ibj...

My sentiments, but not exactly. Not all changes from stock will have a downside equal to or greater than the perceived improvement in performance. If that were the case, the factory would not have made any changes to the bikes as they evolved.

I do wish people wouldn't remove catalytic converters from vehicles that have them. I figure that either they think they are so important that others should pay with their health for a perceived performance enhancement or they may be so young that they don't have an appreciation for how bad the air was, say, back in 1970.

Disclaimer: My 1964 VW bug puts out probably at least the smog of 100 Honda Civics.

Chuey

[Major Softie]

I know I'll catch a LOT of guff from others about this.

Well, you did ask for it. Much of your post is opinion. I will try to limit myself to the places where you have made statements of fact that are simply incorrect:


A lot of issues here. As mentioned above in khittner1's post, besides the general ugliness and extra weight of the injection system, there are genuine reliability issues impacted by the system. As to the rest:

Do yourself, the other people in the world and especially the next owner of the machine a huge favor and leave the equipment on the bike that BMW designed to be there.

BMW never would have put those parts on if they were not forced to do so. That does not, in itself, make them bad parts, but your statement is very misleading. The engineers never would have chosen to put those parts on if not forced to do so. In other words: the engineers that designed that engine did not want those parts on the machine.

I recently acquired a California 1998 R1100RT that some previous owner had removed the evaporative emissions charcoal canister from and, of coarse, discarded all those parts. It cost me hundreds of dollars and weeks of work to obtain all the needed stuff to get the thing back to original condition.

Very different. The evaporative canister truly does have zero impact on the performance of the bike. It is, at worst, a minor aesthetic irritation. However, on some other bikes, that is not the case. For instance, my 07 Duc mounted the canister sticking out from the side of the engine in the most hideously obvious statement of: "you've forced us to put this on, and we're going to put it here as big and ugly and stupid and in the way as possible so that our customers will just take it off." I immediately removed it (and put the parts away on the shelf in case of need or later sale of the bike). My R1100RS still has its canister, as it is installed in a perfectly reasonable and sensible way.

You'll hear 100's of stories about the huge determents that are supposedly caused by modern emissions equipment on the bike.

That air injection system does not qualify for your phrase "modern emissions equipment." It was a cobbed up, patchwork, hideous bandaid. It was poorly engineered, and accomplished little toward its intended goal.

Leave the machine completely stock. You'll have a much better overall rider experience and maintain a far better resale value when you're ready to trade & move up.

None of this is true. Stick to your environmental arguments. This argument is specious. There will probably come a day when an 80's Airhead will be more valuable if it is absolutely bone stock than if it has been modified for better running and reliability, but that day is probably 30 years in the future.

If you want a machine with no such equipment, just by an older less technical machine.

Without even getting into the misnomer of a "less technical machine," hopefully you do realize that riding around on an older version of the same machine that has no emissions equipment at all has exactly the same environmental impact as riding around on one that has had the air injection system disabled. Thus I do not see the relevance of this statement.

Although it is likely that the average user will not ever see or realize the difference in performance, reliability and or drivability, every change made from the stock design will always have a downside equal to or greater than the "perceived" improvement in performance.

This is entirely false. It is certainly true about some modifications, but it is an absolute fallacy to say it is true about every possible modification. Even removing the harmless evaporative system fails to fit this description. As for the rest: the drivability of motorcycles from every company was compromised for the poorly conceived bandaid experiments tried though this period to lower emissions. Until the advent of fuel injection, and then catalytic converters, few of the factory "solutions" were very acceptable choices. Your confidence in the perfection of the compromises made by an engineering team constrained by law, marketing, current technology, and cost, is, to put it extremely kindly: thoroughly misplaced.