BMW K bikes (Bricks)

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1Back to top Go down    Vacuum Lines, 85 K100RT? on Tue Oct 31, 2017 6:36 pm

flyinglow

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The K100RT I purchased recently was a little difficult to start and wouldn't run very smooth until it really warmed up. Much more cold blooded than the two other K100RT's I previously owned. I pulled the plugs and all 4 were a dark and a little sooty. It only has 30,000 miles so I decided to check the fuel pressure, which was fine, then pull all the injectors to clean and test them. Once removed, the inner O-rings on the injectors, engine side, were a little hard so I got all new ones. I bench cleaned the injectors and tested the spray pattern and all looked good. I was about to reinstall them and took a close look at two vacuum lines, one at cylinder one throttle body and one at cylinder four throttle body. I was surprised to see both rubber lines were cracked at the very end that pushes on the stub. Can anyone tell me what function each of these have and where they go under the tank. It looks like I will now need to remove the tank and air box to replace these hoses. I was going to insert a picture to make it more clear but when I clicked Insert image it asked me for a URL?? The pic is on my computer so I gave up.

    

2Back to top Go down    Re: Vacuum Lines, 85 K100RT? on Tue Oct 31, 2017 6:51 pm

Laitch

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@flyinglow wrote: I was going to insert a picture to make it more clear but when I clicked Insert image it asked me for a URL?? The pic is on my computer so I gave up.
Be adventuresome! Click the icon to left of the one that disappointed you. Select the image from your computer, click the Save All button, wait a moment until the image appears in the utility box, then click Insert All and it will appear in the Reply box.

The hose connected to the #1 port is probably attached to a vacuum switch behind the throttle bodies. The switch is regarded as ineffective and was discontinued. Disconnect the hose from the switch and the port then cap the port.

The hose from the #4 port goes to the fuel pressure regulator behind the throttle bodies. Replace the deteriorating hose with high quality vacuum hose.

An image of the switch and the fuel pressure regulator at the rear of the throttle bodies is found in this post.


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1995 K75T 68,000 miles
    

3Back to top Go down    Re: Vacuum Lines, 85 K100RT? on Wed Nov 01, 2017 5:21 am

92KK 84WW Olaf

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If you have a little manual dexterity, as said plug the front one with a vacuum cap same as you see on 1 2 3 manifolds. The vacuum line at 4 you can get at from the right hand side, if you take off the bottom of the air box. Its got 2 Allen bolts inside down on to the top of the engine. Copious WD40 helps. I didn't take tank off to do mine.

BUT if you have found that you should also replace the fuel lines from the tank to the injector rail, tank to fuel pressure regulator to the injector rail. These go hard and crack and split.....especially if you have tank on and off. Make the two front ones about 1 1/" longer and refilling the cooling system or accessing relay box no longer involves removal of the tank. Also, you likely have the bolt down tank with the electrical connector at the front left, close up the pins a little to improve the electrical connection.


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1992 K100LT 0193214 Alaska Blue 101,000 miles
1984 K100RT 0022575 Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Mystic Red 58,645 now 80,700 miles
    

4Back to top Go down    Vacuum Line pics on Wed Nov 01, 2017 11:46 am

flyinglow

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5Back to top Go down    Vacuum Line pics on Wed Nov 01, 2017 11:57 am

flyinglow

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Thanks for the posting directions and info.

    

6Back to top Go down    Re: Vacuum Lines, 85 K100RT? on Wed Nov 01, 2017 1:16 pm

92KK 84WW Olaf

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This one I replaced from theright handside, tank off doesn't let you access this. Had to take bottom of airbox off [2 bolts as mentioned and copper paste them for going back in]. I fed a long length of vacuum tube in from the left side where you can see the tubego through, thenon the airbox side was able to grab it and slip it on to the fuel pressure regulator. [Getting the old one off was a bit harder though, needed a knife to cut it]. Then back to left side of bike, cut the tube and slipped it on. If you use a precut length you have nothing to grab hold of and work with......

I just head down to the local BMW dealer for most of these things and ride into the Honda main dealer next door, they stock the right tube at the right price.


__________________________________________________
1992 K100LT 0193214 Alaska Blue 101,000 miles
1984 K100RT 0022575 Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Mystic Red 58,645 now 80,700 miles
    

7Back to top Go down    Air Box Removed on Fri Nov 03, 2017 11:41 am

flyinglow

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I ended up taking out the top and bottom of the air box because once the bottom is removed it is easy to take the top out and then you have lots of room. I replaced all the vacuum and fuel hoses, adding a little length like suggested. Now that I'm in there I'm also going to replace the fan with the SPAL, as it is getting noisy and add a manual switch.


    

8Back to top Go down    Re: Vacuum Lines, 85 K100RT? on Fri Nov 03, 2017 12:11 pm

Laitch

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@flyinglow wrote:I replaced all the vacuum and fuel hoses, adding a little length like suggested.
Clamps used on fuel injection high-pressure hoses provide uniform clamping pressure. Unlike the ones you are using, they do not have perforations. Here are images of this type of clamp in two styles.


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1995 K75T 68,000 miles
    

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