Won't start

Cablebeacher · 1 Won't start - yet again Tue Jul 18, 2023 2:22 am

Cablebeacher

Silver member

Number of posts : 84

Hi all

Time for the cavalry. I have been at this problem off and on for a couple of weeks and can't see the trees anymore. I have earched the forum but can't find an answer...

1. Bike was not started for along while (months)
2 Wouldn't fire. Had no noise at fuel pump.
3 Pulled it out and found the crud issue (again!)
4. Cleaned it all out. Cleaned the motor and it run and bench pumps fuel. Battery fully charged and strong.
5. Replaced the internal fuel filter.
6 Rebuilt the 4 injectors. Tested. All ok.
7 Pumps fuel at LHS end of fuel rail
8 Still won't fire.
9 Checked and cleaned spark plugs. All fine
10 Tried Starting Spray into cylinder 1 and start. No. Pulled the plug out and it seemed to be dry...

Question: should the pressure at the LHS end of the fuel rail be fairly strong when you press the start button?

and

If I disconnect the complete fuel rail and press Start will the system fire fuel out the injectors?

Other than that any advice welcome.

Regards

Mal
Cable Beach
Western Australia

Rick G · 2 Re: Won't start - yet again Tue Jul 18, 2023 4:06 am

Rick G

admin

Number of posts : 12054

It should spray fuel out the injectors (be careful to have the spark plugs in and leads on the plugs, prevents open sparks) I have used a piece of cardboard or stiff paper so you can see the spray pattern as the injectors fire. The grey side of the cardboard is best as the wet surface shows out best.

92KK 84WW Olaf · 3 Re: Won't start - yet again Tue Jul 18, 2023 7:26 am

92KK 84WW Olaf

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Number of posts : 7954

What bike/year is it?

Cablebeacher · 4 Re: Won't start - yet again Tue Jul 18, 2023 8:08 am

Cablebeacher

Silver member

Number of posts : 84

Hi OLaf

1983 K100RS

Didn't think that would matter...

Regards

Mal

Point-Seven-five · 5 Re: Won't start - yet again Tue Jul 18, 2023 9:59 am

Point-Seven-five

Life time member

Number of posts : 4216

Did you flush the rail when you cleaned the rest of the system?

If the injectors had dirt in them, then it makes sense to me that the rail would be full of dirt as well. If you didn't flush it well, then as soon as you started the fuel pump the injectors may have clogged again.

92KK 84WW Olaf · 6 Re: Won't start - yet again Tue Jul 18, 2023 11:58 am

92KK 84WW Olaf

Life time member

Number of posts : 7954

Cablebeacher wrote:Hi OLaf

1983 K100RS

Didn't think that would matter...

Regards

Mal

It does because later K bikes with 16v engines the system is different and the fuel pump actually primes when you turn it on and has a side stand switch to disable it.

2v Ks only run fuel pump when you press the start button. In all cases you need neutral light on or pull the clutch lever [it has a switch that must be working].

Your 83 K also has known issues with the electrical plug into the fuel tank that can result in no power to the pump in the tank but then the pump will run ok on a bench test. These will give no fuel in any of the injectors. The fuel injection system operates by controlling the earth side, live is permanetly live. That earth is under the control of the neutral light/clutch switch.

Did you actually test for spark? If no spark AND no fuel then different cause would need to be investigated.
Could tank pipes be wrongly connected at the front of the tank?...there is a non return valve in it too.
Fuel filter correct orientation?
Connections to the fuel pressure regulator correct?

costellon · 7 K100 no start Tue Jul 18, 2023 1:56 pm

costellon

active member

Number of posts : 38

Hi.
100% with Point 75 - be sure and clean the fuel rail properly. Also, Olaf is bang on.
I've got a k75 and had a similar problem last week. Pump bench tested fine etc ....

I wasted a lot of time by overcomplicating things and AFTER checking everything else - I checked the wires to the fuel pump for continuity from the connector - found a bad connection inside the tank - where the FP + solders onto the block - I re-soldered it - had full continuity and then checked the connector from the wiring loom for power/ earth.
I had continuity to inside the tank from outside and had power/ earth from the loom to the WIRES but not as far as the loom connector.
I bypassed the connector and the problem is sorted.
So I had 2 problems, dodgy connection inside the tank and dodgy connection outside.
Also, listen for the FI relay under the tank when you press the starter button - it should click when you press the starter button (powering up the fuel pump inside the tank - you should hear it whirring) and click again a few seconds after you take your finger off the starter button - and the whirring inside the tank should stop.
I know im stating the obvious but in hindsight the simplest tests may not always be the first that spring to mind.
Hope this helps.
Cheers

Last edited by costellon on Tue Jul 18, 2023 3:41 pm; edited 1 time in total

duck · 8 Re: Won't start - yet again Tue Jul 18, 2023 2:11 pm

duck

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Number of posts : 4443

To see if the fuel pump is running put your ear to the left side of the tank while hitting the start button and you should hear a whirring noise.

lucki · 9 Re: Won't start - yet again Wed Jul 19, 2023 9:54 am

lucki

Silver member

Number of posts : 165

Came across a Chris Harris video about a k bike that sat a while would not start. It had fuel and spark still no go. he put a teaspoon of oil in each cylinder to increase compression, started.

duck · 10 Re: Won't start - yet again Wed Jul 19, 2023 10:23 am

duck

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Number of posts : 4443

lucki wrote:Came across a Chris Harris video about a k bike that sat a while would not start. It had fuel and spark still no go. he put a teaspoon of oil in each cylinder to increase compression, started.

Whenever I bring a K back from the dead I spray fogging oil into each cylinder before attempting to start it.

Rockman · 11 Re: Won't start - yet again Wed Jul 19, 2023 7:54 pm

Rockman

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Number of posts : 517

Rick G wrote:It should spray fuel out the injectors (be careful to have the spark plugs in and leads on the plugs, prevents open sparks) I have used a piece of cardboard or stiff paper so you can see the spray pattern as the injectors fire. The grey side of the cardboard is best as the wet surface shows out best.

Be careful if you do this. Even with the spark plug leads attached it still can ignite the fuel spray through flame coming back through the injector holes in the head. Leads to some exciting moments. I'd make sure the fuel spray was as far away from the holes as possible before attempting it, and have a fire extinguisher handy.

Point-Seven-five · 12 Re: Won't start - yet again Wed Jul 19, 2023 8:28 pm

Point-Seven-five

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Number of posts : 4216

Get four soda bottles and stick the tip of each injector into a bottle to catch the fuel spray. You can see the spray pattern through the side of the bottle.

Dai · 13 Re: Won't start - yet again Thu Jul 20, 2023 7:10 am

Dai

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Number of posts : 5698

Rockman wrote:Be careful if you do this. Even with the spark plug leads attached it still can ignite the fuel spray through flame coming back through the injector holes in the head. Leads to some exciting moments. I'd make sure the fuel spray was as far away from the holes as possible before attempting it, and have a fire extinguisher handy.

You've been there too? Very Happy

Cablebeacher · 14 All is well! Thu Jul 20, 2023 7:55 am

Cablebeacher

Silver member

Number of posts : 84

Hi all

Thanks to you all forgetting involved. The main outcome was to push my re-start button and clear the fog that was in my brain. I took on board all the suggestions and have spent most of today sorting it... It was a case of everything that could go wrong did.

1. No fuel in the cylinder/spark plug. Went back to the new fuel pump which had been bench tested. No fuel coming out LHS Fuel rail. In tank no fuel coming out pump fuel nozzle. Pulled pump out again. Wouldn't fire. Bench test with 12v and it fired. Put back and it fired (whirred) but no fuel.
2. Checked previous non-genuine small red pump I was using to find these terminals were opposite to Bosch/Qantum. So the new pump was sucking not pumping! Fixed with new connectors?
3. Fuel now coming out LHS fuel rail. Pulled rail out to check injectors. Fuel now coming out injectors. Replaced Injector/fuel rail/ Crimped one of the O rings and had a leak. BUT the bike started but ran rough and eventually dropped revs until it stopped.
4. During this process I found if I hit the Start button while it was running it would pump more fuel (?) and the revs increased. Thought it must be fuel pressure...
5. Replaced injector O ring. No leaks. Bike started but same problem with holding revs - start button "helping" as above.
6. Took Qantum pump out again and bench tested flow against Non genuine pump (#2 above). Seemed similar. Returned Qantum thinking it could be Fuel Pressure Regulator...
7. Went to check pump with no fuel line connector on pump. Don't know why! By this point I was getting foggy again. Looked in tank to check while starting and thought: "What is that big stream of fuel spurting around the other end of the tank near the filter?".
8. My newish fuel line had a fairly good split in it and was spraying everywhere but only after I had moved the fuel filter.. Fuel was previously spraying back into existing petrol and was invisible. New replacement fuel line.
9. Hit start and it fired up and purred. I swore at every component. Several times.

Will take it to our only bike shop within 2000kms in both direction and hope they can balance the carbs and check the fuel pump pressure with a view to replacing Fuel Pressure Regulator?

Again thanks to everyone for advice.

Final question: does anyone bother with the supplied rubber boots for the internal fuel pump connectors or are they just more rubber to perish?
Thanks in advance

Mal

92KK 84WW Olaf · 15 Re: Won't start - yet again Thu Jul 20, 2023 7:08 pm

92KK 84WW Olaf

Life time member

Number of posts : 7954

Reading your last post I would hold back on the fuel pressure regulator.

You have issues in the tank that I dont feel are permanently sorted. March last year I took everything out of the tank on my 83 RS, replaced everything wih brand new. Filter, pump, pipes. clips, mount, vibration damper, pump basket.

I got another K last March that I intend to take to England in 2 weeks and then Spain and France in about 6 weeks, I am going to do the exact same, take out everything.

Having done that then do a balance and it should be good to go.

As for balancing the 'carbs' can you get a Carbtune and do it yourself? Folks here will explain how to do it.

duck · 16 Re: Won't start - yet again Thu Jul 20, 2023 7:20 pm

duck

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Number of posts : 4443

92KK 84WW Olaf wrote:
As for balancing the 'carbs' can you get a Carbtune and do it yourself? Folks here will explain how to do it.

http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/tbsync/tbsync.htm

Cablebeacher · 17 Re: Won't start - yet again Fri Jul 21, 2023 6:26 am

Cablebeacher

Silver member

Number of posts : 84

92KK 84WW Olaf wrote:Reading your last post I would hold back on the fuel pressure regulator.

You have issues in the tank that I dont feel are permanently sorted. March last year I took everything out of the tank on my 83 RS, replaced everything wih brand new. Filter, pump, pipes. clips, mount, vibration damper, pump basket.

I got another K last March that I intend to take to England in 2 weeks and then Spain and France in about 6 weeks, I am going to do the exact same, take out everything.

Having done that then do a balance and it should be good to go.

As for balancing the 'carbs' can you get a Carbtune and do it yourself? Folks here will explain how to do it.

Hi Olaf

Thanks for this. I did replace everything in the tank EXCEPT two fuel hoses as I did them late last year... Should have done them as well...

I went to the local bike shop to find he has no mechanic, a young First Year apprentice who has only done 1 balance at the TAFE Training facility and he can't fit me in for another month!
I will research the balance kits and get one!
Regards

mal

Point-Seven-five · 18 Re: Won't start - yet again Fri Jul 21, 2023 8:43 am

Point-Seven-five

Life time member

Number of posts : 4216

Here is my Cheap Bastard substitute for the Carb Tune.

Laitch · 19 Re: Won't start - yet again Fri Jul 21, 2023 9:06 am

Laitch

Life time member

Number of posts : 3250

Point-Seven-five wrote:Here is my Cheap Bastard substitute for the Carb Tune.

This substitute is also known as a Looney Tune in some regions, costs less than a loonie to make (if you donate your time), and works well. It doesn't come with instructions. You need to make those, too. Laughing

92KK 84WW Olaf · 20 Re: Won't start - yet again Fri Jul 21, 2023 2:52 pm

92KK 84WW Olaf

Life time member

Number of posts : 7954

Cablebeacher wrote:

92KK 84WW Olaf wrote:Reading your last post I would hold back on the fuel pressure regulator.

You have issues in the tank that I dont feel are permanently sorted. March last year I took everything out of the tank on my 83 RS, replaced everything wih brand new. Filter, pump, pipes. clips, mount, vibration damper, pump basket.

I got another K last March that I intend to take to England in 2 weeks and then Spain and France in about 6 weeks, I am going to do the exact same, take out everything.

Having done that then do a balance and it should be good to go.

As for balancing the 'carbs' can you get a Carbtune and do it yourself? Folks here will explain how to do it.

Hi Olaf

Thanks for this. I did replace everything in the tank EXCEPT two fuel hoses as I did them late last year... Should have done them as well...

I went to the local bike shop to find he has no mechanic, a young First Year apprentice who has only done 1 balance at the TAFE Training facility and he can't fit me in for another month!
I will research the balance kits and get one!
Regards

mal

A word of warning. Don't go at this without doing our research. Its not difficult, but there are screws there you must not ever touch or you will create issues for yourself. Dont let the first year guy at your bike. Its easy to set the Carbtune up, you wont do much issue at that point, just dont adjust anything. But before you do that, check your vacuum caps and the vacuum pipe at no 4 that goes back to the fuel pressure regulator. They are likely to be perished and cracked and need replacement. Go buy some caps and vacuum line. If yours is an early K you will need 4 caps, not 3, you will use 2 of them at no 1 cylinder at the front.

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1 Won't start - yet again Tue Jul 18, 2023 2:22 am

Cablebeacher

2 Re: Won't start - yet again Tue Jul 18, 2023 4:06 am

Rick G

3 Re: Won't start - yet again Tue Jul 18, 2023 7:26 am

92KK 84WW Olaf

4 Re: Won't start - yet again Tue Jul 18, 2023 8:08 am

Cablebeacher

5 Re: Won't start - yet again Tue Jul 18, 2023 9:59 am

Point-Seven-five

6 Re: Won't start - yet again Tue Jul 18, 2023 11:58 am

92KK 84WW Olaf

7 K100 no start Tue Jul 18, 2023 1:56 pm

costellon

8 Re: Won't start - yet again Tue Jul 18, 2023 2:11 pm

duck

9 Re: Won't start - yet again Wed Jul 19, 2023 9:54 am

lucki

10 Re: Won't start - yet again Wed Jul 19, 2023 10:23 am

duck

11 Re: Won't start - yet again Wed Jul 19, 2023 7:54 pm

Rockman

12 Re: Won't start - yet again Wed Jul 19, 2023 8:28 pm

Point-Seven-five

13 Re: Won't start - yet again Thu Jul 20, 2023 7:10 am

Dai

14 All is well! Thu Jul 20, 2023 7:55 am

Cablebeacher

15 Re: Won't start - yet again Thu Jul 20, 2023 7:08 pm

92KK 84WW Olaf

16 Re: Won't start - yet again Thu Jul 20, 2023 7:20 pm

duck

17 Re: Won't start - yet again Fri Jul 21, 2023 6:26 am

Cablebeacher

18 Re: Won't start - yet again Fri Jul 21, 2023 8:43 am

Point-Seven-five

19 Re: Won't start - yet again Fri Jul 21, 2023 9:06 am

Laitch

20 Re: Won't start - yet again Fri Jul 21, 2023 2:52 pm

92KK 84WW Olaf

21 Re: Won't start - yet again

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