i have brought a 1988 k100rs as a non starter which i am converting to a trike (they don't fall over) .I have isolated the fault to the fuel system , I will give a quick breakdown of the symptoms -
 
Engine spins freely and will start with just the fuel pipe full of petrol (tickover). Using a plastic bottle and tube the bike will start tickover and as long as I press the starter button(excess fuel) will rev nicely.
 On fitting the tank and plugging in the pump wiring as soon as the ignition is turned on the pump will spin and will not ever stop,(the pressure will spurt fuel from the return pipe a good foot in the air) the engine is immediately flooded and will not even fire.
 Removing the plugs and drying them on replacing with the pump disconnected it will instantly start and reconnecting the pump while running as long as you keep it revving it will ride but not tick over . Once stalled you have to remove and dry plugs again.
 I have blocked the return pipe and the pump will slow slightly but will still not stop spinning resulting in engine flooding.
 1  Is the pump stopped mechanically or electrically.
 2  could it be the pressure regulator.
 3  previous owner changed the ignition switch could this cause the pump to over work.
 4  is the pump repairable or sealed.
 5  help.

Addition information fuel tank had leak now repaired so possibly pump was dry for at least 18 months before i brought the bike. absolutely sick of checking hall sensors, modules, fuses,earths so any ideas will be very appreciated.

Pump not repairable but cheap enough in UK on eBay for about £50.

Doesn't sound like the problem though.

But pump running should not flood the engine, the fuel is also controlled by the injectors opening. My pump doesn't appear to run when I turn on ignition or when the kill switch is moved to on position. I say appear to because I can't hear it running.

What happens when you let go of the start button? Does it stay running or cut out?

When you say previous owner changed the ignition switch did he change any wiring?

pump runs as soon as ignition is turned on very noticeable noise, starter button does not stop pump when pressed or released,probably flooding engine as soon as injectors open i believe all injectors open at same time but i may be corrected on this point.with pump disconnected engine will run until pipe is dry.
ignition switch relocated to side -right knee- so only he knows what he has altered.
pump constant pumping all the time ignition switch is on it does not cut out on pressure reached just constant whirring.
thanks for the reply.

The fuel system uses a fuel pressure regulator to control pressure and pump stays running all the time. I don't think you need be looking at the pump for now, it works as it should.
 
But sounds like something in the ignition rewiring may have caused it to stay running. The flooding may be connected with this as I imagine the injectors should stay closed and not permit flooding unless this is being caused by a wiring/temperature sensor issue.

There are some very good interactive wiring diagrams on the forum portal and worth looking at these. Even though I have been on Ks 7 years and been in under the tank lots of times I have been fortunate not to have had to go into wiring issues and don't know the wiring all that well.

There are a few potential causes most of which require patience and a little but very methodical testing rather than a wallet!

You will get better posts in a while from those who know the wiring better.

thanks for your help  hopefully will get it sorted but definitely done my head in so far.still think pump should stop once pressure is reached but time will tell.thanks again.

triker wrote:thanks for your help  hopefully will get it sorted but definitely done my head in so far.still think pump should stop once pressure is reached but time will tell.thanks again.

It doesn't stop once the bike is running, triker, unless it is faulty or not receiving power. Check the fuel return line to be sure it isn't clogged. Look at the troubleshooting chart, available in the site's portal that Olaf mentions,to review explanations of the bike's various systems so you will gain a better understanding.

This is the link:

http://k-bike-knowledge.000webhostapp.com/Downloads/electrical/diagrams/interactive_diagrams.htm

But do remember the fuel pump stays running. Think of it as inflating a balloon with a small hole in it and constantly keeping it inflated as the air leaks out. Same as the fuel pressure relay returning fuel to the tank while keeping the fuel under pressure.

Might be no ram if you can to pop up  photo of where the ignition is now located and a photo of what's there under the tank.

92KK 84WW Olaf wrote:
But do remember the fuel pump stays running. Think of it as inflating a balloon with a small hole in it and constantly keeping it inflated as the air leaks out.

Or think of it as a benign species of bagpipe.

Laitch wrote:

92KK 84WW Olaf wrote:
But do remember the fuel pump stays running. Think of it as inflating a balloon with a small hole in it and constantly keeping it inflated as the air leaks out.

Or think of it as a benign species of bagpipe.

Ha do I hear a drone?

I do love the bagpipes and that's exactly how they work. Much better description.

thanks for the useful information and the link i will be scrutinizing this in depth as for posting a picture i can only just manage a keyboard have to wait for my son to do technical stuff like that .brilliant to be able to get help like this thank you all for your replies. I will keep you all informed as to what i find. oh and petrol is squirting back into tank so pretty sure return is clear. ignition wiring could be the problem will check it out.

checking and a lot of reading and following diagrams I think the pump is possibly connected to the wrong connector, it was and is plugged into the box under the seat to the white connector which could be the security type of device.
Now all i have to do is try to locate the pump / fuel level connector which could be anywhere .Would i be right in assuming it to be black in colour and in front of the wiring box.Will try to check tomorrow.fingers crossed.

On my bikes it is a black connector along the top rail rail of the frame behind the Right side battery cover just below the back end of the tank.  It might have a tag on the wire leading to it that says "tank".

if i find it and it is marked tank i think i will just shoot myself

A four wire connector behind the R/H batt cover will have a green wire with a white stripe a brown wire a all white wire and another mightbe black, anyway that connector has four wires in it and a extra hole on top of the four. That one is where the tank connects into. By all rights the bike should switch on and the second you touch the starter you'll hear the pump run. Now if you don't start the bike straight off and only crank the starter half a smidge and it don't fire, the last thing you should hear is the fuel pump run for 3 or 4 seconds and stop.
That will tell you, you are on the right connector. We'd expect it to start if you thumped the starter for a second or more.

Hope this is clear enough for you.

The pump should deliver fuel to the fuel rail and straight back round via the fuel pressure regulator and back into the tank. All hooked up you should be able to start run and warm up the engine. It might even Idle when your finished. The rear hose goes to the front of the fuel rail and the front tank nossle is where the fuel returns into the tank.

thanks for that ,i will check it out but as your explaining the pump should stop when the engine is stopped mine keeps running as if it has a positive direct from ignition switch.Saying that if it is plugged into the wrong connector it probably is.The previous owner altered most of the bike i,e - unfaired,all lights changed ,bare wires behind dash etc and started to fit rear axle/subframe, got out of his depth and abandoned the project and ignored it for the last 18 months.wiring is all over the place so if the connector is missing i will rewire it following the diagram supplied earlier. i will keep you all informed of what i find.

On another note why is my dash displaying number 4 for neutral (no light) and 5 for first is it just a very confused bike because i know i am.

'Coz the GIS (gear indicator switch) is full of shite. If you're converting to a trike you'll find it behind the swingarm when you take the swingarm out. It's secured by two small screws, both of which are probably corroded in solid. The rubber cover goes rotten over time and allows water into the switch. The cover can be prised off and the guts of the switch cleaned, but when you dismantle it, do it in a bucket. There's three very small ball bearings and springs in there and they will attempt to hide in the dirtiest, shitiest part of your garage floor.

Whose rear-end are you using? Trike Shop, Panther Trikes or...?

About the malfunctioning GPI....you probably have a open circuit in the yellow/white wire, between the switch and the instrument.
Or a bad connection in this specific circuit inside the switch itself.

trike rear end is home made already assembled and using reliant robin rear axle ,reworked frame on rear to take shocks to retain soft tail ,so switch is already on display so hopefully should be removable without to much fuss but will check circuit first and wiring looks set to be a wealth of possible problems.thanks for the replies.
 with this much info available do you lot spend all your time fixing these things i was told they were reliable

triker wrote: but will check circuit first

As a test, ground the yellow/white wire.....1st and neutral should then show
normal numbers in the display.

triker wrote:trike rear end is home made already assembled and using reliant robin rear axle ,reworked frame on rear to take shocks to retain soft tail ,so switch is already on display so hopefully should be removable without to much fuss but will check circuit first and wiring looks set to be a wealth of possible problems.thanks for the replies.
 with this much info available do you lot spend all your time fixing these things i was told they were reliable

Is the Reliant final drive mounted upside down?

Ks are reliable but most of us are starting with neglected Ks which need rehabilitation. Once sorted they are extremely reliable. Just keep a simple maintenance regime.

no the axles the same way up, when i have rode it (running badly) acceleration is good and final drive ratios seem fairly close .running 16 inch rear wheels with 205/40 tyres.   Will be towing trike on back of camper van with front wheel raised rear wheels turning, the diff should be alright but will the bmw gearbox like it or should i remove prop to go long distances any views would be appreciated .

Remove the propshaft. Definately remove the propshaft. When towing you're loading the gearbox the wrong way.

As for reliability... I've run off 60,000 miles in four years with just routine maintenance (after I'd sorted all those 'orrible niggly problems it came with ).

I have a friend locally has a trike with a Reliant rear end but I wasn't sure which way the engine rotated. Its upside down due to the engine rotation.

You need a new source of getting a signal for the speedo as the K speedo sensor is on the rear final drive.

The K gearbox oil content is not a lot, not like a car with a few litres.

Dai wrote:Remove the propshaft. Definately remove the propshaft. When towing you're loading the gearbox the wrong way.

I remember towing (i.e. driving the rear wheel with gearbox in neutral) being discussed in a previous post where the risk of having something flick up from the road and contact the selector pedal was discussed. Dai may have a point in regard to the gearbox not liking full time towing in neutral.... Initially I thought the Guinness had got to him but remembering the extent to which he has impressed in the past, I felt I owed it to him to at least think it through.

The reason I think he has a point is because this towing scenario would involve not just full time engine breaking mode instead of part time breaking mode in terms of the (albeit minimal) loading of tooth flanks. There is also the fact that whereas in normal engine breaking mode, the gearbox is in gear by definition, and all three gearbox shafts are rotating thus ensuring adequate lubrication to the critical output shaft. When the bike idles in neutral, the input shaft and lay shaft rotate and throw oil, some of which is collected and gravity fed into the hollow output shaft via a catcher arrangement in the front cover. This is essential because although the output shaft is stationary during normal running in neutral, any output shaft mounted gear that meshes with the fixed part of the lay shaft, will still be rotating. When rotating the rear wheel by towing with gear box in neutral, the lay shaft is stationary and therefore the pair of gears that are primarily responsible for feeding oil to the front cover catcher, are also stationary. There is therefore an argument that would support the supposition that there is an oil starvation risk associated with towing in neutral. The fact that there is no normal driving or braking load on the rotating output shaft together with its stationary and rotating gears in this condition, means that the potential for negative consequences may in practice be negligible.

Thanks Dai for giving me the excuse to dig out my spare gearbox parts and do what for me is now a bit of major grey matter exercise. Given the uncertainty of the risk associated with abnormal lubrication conditions, plus the risk of damage if a bump on the selector were to initiate some serious grinding of gear wheel dogs / stress to selector linkage, I think I would agree that drive shaft removal is probably a worthwhile precaution.

It's a long way of saying +1 for your comment (but I'm sure you know my diatribes well enough to have skipped the above if you're not into the kind of overblown analysis that keeps me happy!)

Excellent and very well put.

Now I went to put up a pint of Guinness and discovered the Guinness is gone.. We need to have a word with Bert.!

rawdonball wrote:Thanks Dai for giving me the excuse to dig out my spare gearbox parts and do what for me is now a bit of major grey matter exercise.

You're welcome

92KK 84WW Olaf wrote:
Now I went to put up a pint of Guinness and discovered the Guinness is gone.. We need to have a word with Bert.!

             

Olaf: For tech support you can call my number: 1-900-555-5555 extension 99999
Standard charges and Long distance charges may apply. Please have your credit card ready!

Ah now I see the stuff is hidden away.

mmmm.


Just as well its there, needed for pudding making soon.

Mines upside down, run with 245 50 14 tyres and robin type A diff (3.2:1) should give around 113 mph at 8500 rpm lol, goes up to the ton
quiet easily

Oh one other thing, my wiring has been cannibalised to the extent that from original only essential engine running and starting circuits remain, this means my fuel pump is ignition switched and as so runs constantly and my starter is triggered from the ignition switch, it does not effect the engines running or starting in any way.

Gauntlett wrote:Mines upside down, run with 245 50 14 tyres and robin type A diff (3.2:1) should give around 113 mph at 8500 rpm lol, goes up to the ton
quiet easily

How does that work. Yours is upside down and Triker's isn't?

Has that to do with contra rotating gear boxes or did I miss something there? It's just that on my Sunday breakfasts a few trikes show up and I learned the Reliant drives are upside down which I had to question as my curiosity got the better of me. Apart from one which isn't upside down because it also has a Reliant engine....

My mind struggles to process the idea of a Reliant Robin travelling at 113mph........

I will have to check my axle again it was already connected to a subframe so now i am wondering if i am wrong I cannot remember seeing drain plug at the top but will check and report back,thats the problem with lockup being miles away from home and any phone/internet connection.
 Tomorrow I hope to get a chance to check pump wiring what way axle is up and gips .
sensible advice with the towing aspect I will be disconnecting propshaft whenever it is towed(have to design a space to make sure the spanners stay with trike at all times).
Speedo going to be driven from a kawasaki front wheel which came as part of the deal.
Lastly how much do these engines rely on the exhaust (back pressure?)as will be rerouting under seat in space vacated by rear wheel,will a straight thru be okay .thanks .

Straight through could sound nice...in truth the original exhaust is about as good as you get for bhp but no on ever uses all the power.

i like to be a noisey bugger lets the neighbours know when i,m home.
 My brain is in meltdown with paper and pen and twisting pieces of paper why would a axle turn upside down change the rotation of a wheel what am i missing ,if i put the prop on 180 degrees from original would i go sideways.why cant my single brain cell sort this out.now where is that gun.

Its a case of 5 forward gears or 5 reverse gears......

Take a coin and slowly rotate it between your gingers like a wheel. Bring it down to a surface and it will go along like a driven wheel. Keep turning it and slowly flip it over without changing how you are turning it and bring it back down to the surface...it goes the opposite direction. That's like turning a completed rear axle over to an upside down position.

so what end do i put the handle bars why o why did i start this

Handlebars still go at the front.

Are you sure about that?

Just make sure you always park your bike in the direction you intend to leave. That way you don't need to worry about the answer.....
 

PS I found Bert's beer stash....

Just a hint, there are no drain plugs on a reliant robin axle, if the axle has been over sleeved don't forget to add a breather hole somewhere

I may have to stand corrected, if the parts diagrams are correctly orientated on google , then mine may be right way up, looking forward from behind my nuts and bolts for the two haves are on the left, however there are still no drain plugs.

clever buggers on here ,
found correct wiring connector jammed under new ignition switch connected it and guess what pump works as it should
engine fired into life first press of the switch .
bolts are on left on my diff, the level plug half way up or halfway down so can not really tell if axle is upside down or not,old shock mounting on bottom of axle tube which makes it very possible i was wrong and the axle is indeed upside down,,been testing it around the fields and found if your eyes are shut who cares where the handle bars are.
goes like sh=t off a shovel mainly sideways.
  can not thank all of you enough, now for the g.i.p.s.

clever buggers on here ,
found correct wiring connector jammed under new ignition switch connected it and guess what pump works as it should
engine fired into life first press of the switch .
bolts are on left on my diff, the level plug half way up or halfway down so can not really tell if axle is upside down or not,old shock mounting on bottom of axle tube which makes it very possible i was wrong and the axle is indeed upside down,,been testing it around the fields and found if your eyes are shut who cares where the handle bars are.
goes like sh=t off a shovel mainly sideways.
  can not thank all of you enough, now for the g.i.p.s.

dont ask why i repeat myself ,could be an echo i suppose

Glad you found the problem and I suspect it has given you a few humorous moments but it sure has saved your wallet big time. That's what the forum is about, sorting problems and advice but also adding a little humour and colour to life.

We will be looking to see some photos, plus you might even feel like a little travel!! If you do head right across west and come see us over here. You can meet up with Born Again Eccentric along the way to the ferry as you pass Bristol/Cardiff. He has been known to pop over for an overnight trip and longer.

Very glad it now goes, and you are having so much fun. Sideways through the paddocks, man that would be cool.