Dear gurus,

I'm the proud owner of an '88 K100 RS as of 3 weeks ago.

Since the purchase I've mainly been riding her to/from work to "get her going again after she spent years in a garage with very limited driving. A few issues as they have surfaced, I have been able to address them so far.
I have still not had the time to do the "preventive maintenance after purchase"-tasks that is well documented on the forum.

I'm seeking your advise on a few topics :

1) I experience an intermittently (and temperature sensitive ?) dead speedometer.
I am quite certain it's the electrical connector, If I tough the cable bundle while driving, it'll come back to life, but I have to do this while keeping my eyes on the road.
Can someone help me identify which connector / wire is the speedometer one ? (see attached pictures)

2) I had to access under the fuel tank to repair a leak, so I disconnected the fuel pump connector. After putting it back together, I experienced on 3 occasions a 'surge-effect' on relatively hard accelleration that I would thought was low-fuel, but I had 6 liters left in the tank when I filled her up. As I didn't have this problem before messing with the tank, I suspect the connector. I have not been able to reproduce the problem.

3) There are 2 lines coming out of the bottom of the gas tank. Overfill evacuation and ventilation, I presume ? They currently don't have rubber tubes running down past the engine block, as do my other bikes. Is this normal ? 

4) The attached picture shows 3 tiny tubes with rubber caps on them, behind the injectors (next to the throttle assembly ?). The rubber caps are cracked and I doubt they provide an efficient seal. What is this ?

Your input is highly appreciated.
As I am just starting (little by little) to get my hands dirty and lacking confidence, I hope you can bare with me on these basic questions.

Best regards,
Einar.

 

#1.  There should be a connector for the speed pickup behind the right side battery cover.  Clean it with DeOxit.

#2.  Tank connector.  They are notorious for causing fuel supply problems.  DeOxit is your best friend.

#3.  There should be a black plastic cup that these spigots drain into.  It will have a single hose that runs down behind the rear brake master cylinder.

#4.  Those are the caps for the connections for a throttle body balancer.  Having them not capped will cause a lean mixture at idle and on acceleration that will cause rough running.  The tube closest to the rear is for a hose that goes to the fuel pressure regulator.

Point-Seven-Five, thank you for your quick reply. 
This gives me a plan of attack. Much appreciated. 

I am looking for a good equivalent to DeOxit, as I live in France, to go over all connectors.

Thanks for explaining the rubber caps, definitely a priority to replace them.

ERasberg wrote:Point-Seven-Five, thank you for your quick reply. 
This gives me a plan of attack. Much appreciated. 

I am looking for a good equivalent to DeOxit, as I live in France, to go over all connectors.

Thanks for explaining the rubber caps, definitely a priority to replace them.

You won't find DeOxit here in France as it seems to be a US trade name for something.

Point-Seven-five wrote:#3.  There should be a black plastic cup that these spigots drain into.  It will have a single hose that runs down behind the rear brake master cylinder.

Only in the USA. AFAIK everywhere else the fuel overflow hose just vents to the outside air.

DeOxit is an American trademark for a contact spray cleaner - something like this:

http://www.ebay.co.uk/itm/Contact-Cleaner-Fast-Drying-For-Electrical-Devices-With-Smart-Straw-Spray-250ml-/182815592184?epid=1736424657&hash=item2a90a88ef8:g:QYkAAOSwOfBZ2e0H

I did try searching ebay France for 'Nettoyeur à jet de contact' but I translated something wrong because all I got were disc brakes for an Alfa Romeo...

ERasberg wrote: 3) There are 2 lines coming out of the bottom of the gas tank. Overfill evacuation and ventilation, I presume ?
 

Not exactly. Presuming anything while working with these bikes can lead you into the weeds.

One drains water that might accumulate beneath the fuel cap thus keeping it from infiltrating the tank then mixing with the fuel. When the cap is open, you should see its inlet on the left side of the gasket assembly. The other vents the tank to air.

The hoses are usually routed to exit behind the right foot peg plate. This image shows how they are routed on my bike.

It appears your internet browser has a thing for italian cars, Dai !

thank you for the link, I was asking myself if the WD-40 contact cleaner would be ok to use. I will get one today.

Also, good to know about the overflow hose.

Laitch, thank you for explaining the routing + purpose of the hoses.
I think the hoses are there, just disconnected from the tank in this case, as I remember seeing 2 tubes routed down towards the pegs.
I will investigate.
Very helpful comment.

Two things, the picture above is a 16valve bike and the 8 valve might be different. Not sure what yours is.
WD40 is not a contact cleaner, believe me I have used it throughout my career. The NATO designation for WD40 is PX24, the P denotes that it is a protective liquid. The spec sheet reads that is is a water dispersant with temporary protection qualities for up to 6 months mainly for use on aluminium alloys.
We used to use electrical contact cleaner that was called "Electrolube", but I have no idea if that is still about or if it is for sale to the general public.

I remember Electrolube.

There's a difference between 'WD40' and 'WD40 Contact Cleaner' - at least I hope there is as they're described as having completely different chemical compositions.

BobT wrote:Two things, the picture above is a 16valve bike and the 8 valve might be different.

Which picture, BobT? There are so many of them. My bike is a K75: Einar's is an '88 K100RS.

Laitch wrote:

BobT wrote:Two things, the picture above is a 16valve bike and the 8 valve might be different.

Which picture, BobT? There are so many of them. My bike is a K75: Einar's is an '88 K100RS.

Mine is an 8 valve. I believe the system is similar. I remember seeing two hoses around that area yesterday. They must have come loose from the gas tank or someone forgot to plug them back in.

ERasberg wrote:Mine is an 8 valve. I believe the system is similar. I remember seeing two hoses around that area yesterday. They must have come loose from the gas tank or someone forgot to plug them back in.

Our bikes both have the same arrangement.

When the tank needs to be raised or removed for various maintenance reasons, detaching and reattaching those hoses when necessary can be tedious. Some of us put quick-detach fittings on them. The hoses should be reattached so gas or water is not dumped on the components beneath if circumstances cause them to start draining fluid.

Is there a how-to for putting on quick-connects ? 

I would love to simplify this task, which at a first glance for a new owner seems overly complicated design-wise.
I am not yet used to the added complexity of a fairing. My other bikes are all naked R-boxers.

ERasberg wrote:Is there a how-to for putting on quick-connects ? 

YouTube is where you go to find out.

Don't make it more complicated than it is. These are just small hoses. Some people don't connect hoses to those ports at all; however, if a full tank overheats, gasoline will flow from one of those ports and the hot engine will receive some of it. Not likely unless you're riding in a hot climate or in heavy traffic in warm weather, but it is possible.

You might be able to use an accumulator. It was mentioned in Reply #2 and Reply #5 here. It's a small open plastic box that hooks over the frame. The tank ports dump directly into it. One hose attached to it dumps both fluids behind the foot peg. They can be found on eBay occasionally.

The main message here is get comfortable removing your bike's tank. Make it as easy on yourself as possible because you might need to do it occasionally to make other tasks easier on yourself, too.

Laitch wrote:

ERasberg wrote:Is there a how-to for putting on quick-connects ? 

YouTube is where you go to find out.

The main message here is get comfortable removing your bike's tank. Make it as easy on yourself as possible because you might need to do it occasionally to make other tasks easier on yourself, too.

Laitch, thanks again for you response. Yes for the vent hoses i agree it's not a critical component.

However, removing the tank is a standard procedure good to be familiar with. I therefore think it's wise to install the quick connects on fuel and return line, as it would avoid having to remove fairing + undo the hose clamps in case roadside breakdown etc.

Unless there is some alterantive method...

Don't use the plastic connectors they break (don't ask) brass is the way to go.

I have QD's on my K1200RS as standard and they are awesome. Have changed them to stainless too. First thing I did when restoring my K1 when it came to refitting the tank was to fit QD's. Best mod you can ever do.

Hi KiwiK100

Could elaborate on how you did it, design-wise ?

Did you cut the cable in half and do a male-female connection ?
Or did you have a quick-connect that plugs straight onto the tank outlet ? (I have seen some Moto Guzzi solutions like that)

I'm wondering if I need new fuel lines, andif so how much extra fuel line i must calculate ?
Also if adding length has an impact on fuel supply / pressure ?

Your input would be highly appreciated.
E/

ERasberg wrote:Your input would be highly appreciated.

Here is some input to appreciate, Einar.
https://www.k100-forum.com/t3308-fuel-line-connectors

Thank you for the link.
Seems like a tight fit.

Here is the proper part for those pesky drain ports:

16 13 2 307 467

	AIR ACCUMULATOR	0.03	1	$2.64

No need to mess with disconnects when moving the fuel tank, and at $2.64US it has the distinction of being one of the two or three most reasonably priced OEM parts you can buy for your bike.

ERasberg wrote:Hi KiwiK100

Could elaborate on how you did it, design-wise ?

Did you cut the cable in half and do a male-female connection ?
Or did you have a quick-connect that plugs straight onto the tank outlet ? (I have seen some Moto Guzzi solutions like that)

I'm wondering if I need new fuel lines, andif so how much extra fuel line i must calculate ?
Also if adding length has an impact on fuel supply / pressure ?

Your input would be highly appreciated.
E/

Fitting the QD's is pretty straight forward. With the tank on the bike and the fuel lines visible, pick a spot on each line that is accessible. Mark the fuel line with any permanent marker, remove and drain the tank and your ready to start. Cut one of the fuel lines and fit the QD to each end noting which is male and female. Then cut the second line and fit the QD with the male/female THE OTHER WAY AROUND from the first QD. This is very important so there is no opportunity to mix up the lines. No extra fuel line is necessary however there is room to make them a little longer so you can lift the tank before disconnecting the QD's. This has no impact on fuel pressure. I replaced the fuel lines anyway as I had no idea how old they were. I also replaced the in tank lines but if you replace these be sure to purchase fuel submersible lines.

Thank you for providing the additional information on parts and procedure.  
Very helpful. I will source the parts today and give it a go over the weekend and coming week.

Best regards.

I did forget to mention that you do NOT want the QD's placed in a curve of the fuel line as this would put undue pressure on the coupling. The QD for the forward most fuel line sits just behind the hole in the flange that is on each side of the tank, and the second QD is a little aft of that. When I lift the tank a little both QD's are easily accessible but otherwise are tucked out of sight. There are also plenty of secondhand items available from places like Beemer Boneyard etc as they were oem on many different BMW's including most if not all of the R series from '91 to 09. Many owners would have made the upgrade to stainless/brass QD's and these are the ones to look for. Avoid the oem plastic as they are known for epic fails. Good luck with your project.