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How to: Troubleshoot a bike that wont start

128K views 86 replies 38 participants last post by  Piccolo 
#1 · (Edited by Moderator)
I've been finding that an alarming amount of people are having trouble with bikes that won’t start and most of the threads consist of "My bike won’t start, help". It's extremely difficult to troubleshoot a bike with that little bit of info, but if you follow this guide, you can likely find the problem on your own, or at least get enough info to help us help you.

There are a number of things that can prevent a bike from starting. Almost all of them are electrical. Your first step will be to grab a manual. You will need it to complete the following troubleshooting steps. Your next step should be to develop a systematic approach to your troubleshooting and use known tests (service manual) to rule out possibilities. If you just start shooting in the dark, you may get lucky, but you may never find the answer. I’ve provided ways to test with and without special tools, in many instances here but to do things properly you will need to get a few things.
  • Digital Multimeter, capable of testing resistance, voltage and continuity.
  • Compression Tester
  • Test wires w/alligator clips.

1. Power
This one should be obvious, but your headlights should come on, gauge cluster lights up, and POSTs. If you find that none of these things happen, check your fuses. If your headlight fuse is either absent or blown, your bike won’t start. Charge/replace your battery. If you have a multimeter available test your battery for 12v. If it’s low, charge it. If it's 0, replace it.


2. Fuel Pump and Kill Switch
Is your kill switch set to the "RUN" (down) position? Turn the bike on and flip the switch off/on. You should hear your fuel pump prime. If you do, your kill switch works. Make sure to leave it in the "RUN" position for the rest of this guide. As soon as you turn your key to the "ON" position your fuel pump will make a short 3s whining sound if the kill switch is "on". This is your pump "priming" and sending fuel to your injectors. If this doesn't happen bypass your kill switch by disconnecting the white 7-pin connector on the right side of the bike near the frame (next to the red 2-pin connector). Using a piece of wire and two small alligator clips jump the pins for the White/Black & Black wires on the bike side of the connector (not the switch side). This will bypass your kill switch and should engage your fuel pump as long as your key is in the "ON" position.

If your fuel pump still doesn't prime, test your fuel pump relay (video below) and bench test your fuel pump. To do this, using two wires with alligator clips on both sides connect one to each of the pins inside of the brown connector on the bottom of the fuel pump. Green is ground, and Brown is positive. Connect the green to the negative terminal on your battery (known good 12v power source), and Brown to the positive terminal. Your fuel pump should prime. If it does not, replace it. It's best to do this with the main fuel line coming from the fuel pump disconnected on the injector side and routed into a small container. Once the pump primes, you should see a strong steady stream of fuel. If you do not, replace it.

Note: Do NOT touch the two clips to each other, they will spark, and spark/fuel does not mix. This test is easiest when you have two people, with the fuel tank and battery removed from the bike completely.


3. Switches and Sensors
Okay, so your kill switch and fuel pump work fine but your bike still won’t start… what now? Your Bank Angle Sensor (BAS), Neutral Position Indicator, and Kickstand sensor can all prevent your bike from starting.

How to BY-PASS Bank Angle Sensor or TIP Sensor remove the sensor located underneath your 3rd Eye Headlight and use a wire with alligator clips on each side, connect one clip to the pin for the green wire and the other to the Red/Blue wire on the harness side of the sensor.

Next, you’ll need to disconnect your kickstand sensor. The connection can be found by tracing the harness going to your kickstand. All you need to do is disconnect it.

And your Neutral Position Indicator sensor will need to be tested using the method shown in the attached picture.

Once all 3 sensors are bypassed/tested, try to start the bike. Make sure you’re in neutral when you do this. If your bike starts, it’s all a matter of the process of elimination. Put each sensor back 1 at a time and try to start the bike after. When it fails, you know what your problem is. Replace.


4 Ignition, Fuel & Compression
Okay, still won't start? Now what…

There are three things required to make a motor run. Ignition (spark), Fueling and compression. We’ve already done a majority of the testing for fueling in step 2 so we will bypass that for now. It's still possible that your injectors are clogged, but I’ve never seen it happen.

To test ignition, remove each spark plug and visually inspect the electrode. If it’s wet, you fouled your plug and it will need to be replaced. One spark plug at a time, Connect the ignition coil (boot) to the plug and hold the grounding stripe to the frame and attempt to start your bike. Make sure you’re holding the very top of the boot and no part of your (gloved) hand is touching the spark plug itself. Your plug should immediately spark multiple times to the stripe. Hold the starter for about 1-3 seconds each so that you can make sure you get a good spark. If you don’t get a spark on any particular spark plug, try swapping out the ignition coil with the coil from a different cylinder. You can see where I’m going with this. Replace the ones that need it. If you don’t get a spark from any coil, make sure your kill switch is still in the run position and make sure each of your main wiring harness connections for the coils and the primary harness connection is nice and clean/tight.

I like to test compression as I test spark for each cylinder. It’s easier not having to R&R spark plugs multiple times. A compression tester is $20 from Harbor Freight. Keep in mind this is a very cheaply built tester and the design is poor. This style tester has the check valve at the gauge instead at the end of a pressurized hose. Because of this design, the tester will add volume to the cylinder which means your readings will be significantly lower than what’s indicated in the manual. The manual indicates 178psi for each cylinder. These test kits will usually indicate around 120psi. To test compression, thread the tester into the plug hole using the appropriate adapter, hold the throttle at WOT and attempt to start the bike. Give it a chance to turn over a few times to build compression, and you should see the values on the gauge go up. Once it steadies up (usually around 3 complete cycles) you should have your results. You're looking for around a 10% uniformity between each of the cylinders. If your results are significantly below the expected values, take your bike to a shop, you will need motor work. Most likely a blown head gasket or piston rings. If you've gotten to this point, you've likely already seen issues with the bike overheating, losing coolant, or other temperature-related problems.


That should pretty much cover like 90% of all of the “My bike won’t start threads”. Questions or comments, let me know. Or if I missed anything.

Note: for some of the electrical connections (the female ones) you will need to use a small probe or solid copper wire stripped on each end to bridge the connection.

Always use insulated tools and a gloved have when touching wires.

 

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#8 ·
People don't believe me when I tell them he is one of the best mechanics in town. Not only does great knowledge of bikes but he will never leave any job undone and unless he is satisfied. Great write up Armando, great idea to help with some troubleshoot.
 
#9 · (Edited)
Guess I never really made that connection. Makes sense. I always just referred to them as if they were synonymous, I think it stems from the fact that I've never actually seen a device that only does one thing. They are all Multimeters.

I mean, yeah, I've used micro-ohmmeter a and milli-ohmmeters etc but never really had a use for one.
 
#13 ·
Hello Fellow RR Enthusiasts not trying to be cocky or come off arrogant but this isn't my first rodeo with any of these repairs or steps IN trouble shooting this problem. And i wvirginia10850ent through every one multiple times now. So my question for this super sticky dead thread is why will it still not start ? All I get out of it is a big click out of the starter relay.
 
#14 ·
That should pretty much cover like 90% of all of the “My bike won’t start threads”. Questions or comments, let me know. Or if I missed anything.
The thread wasn't meant to be an end-all be-all to troubleshooting threads. But, for your problem. The click, is it coming from the relay or the starter?

If it's coming from the starter, than there's a good chance it, or a gear in your starter clutch, needs to be replaced.

If it's coming from your relay, you need to take a second look at your battery and the relay. Put a meter on the battery and see what it reads with the key off, on and when you hit the starter. If it drop below 7ish when you try to start the bike I would replace the battery. Also, lookup the specs on your battery and determine the CCA it should be putting out and test it, if it's below the required amperage it will cause your relay to click. Charge it and test it again. If it still fails to put out the require amperage, replace it.

The tricky thing about batteries is that they can read +12v but fail a draw test. Also, a battery can seem like it's fully charged, or instantly charge when put on a charger, but that typically means a cell is dead.

Also, I've seen quite a few cheap batteries dead, brand new. So... test it. Don't just assume that it's good if it's new.
 
#20 ·
What sort of movement? It comes up normally, if that what you mean...along with other LED on the meter instrument. Just the FI not lit and no fuel pump sound. I've done all the troubleshooting steps according to the workshop manual and al, checks out fine.

Could any short/open circuit cause the ECU to burned?
 
#27 ·
Any results on all the tests and after fixing the wire?

I believe there isn't enough power coming thru the relay, thus you can hear it clicking, but the engine won't move a bit.

Have you checked R/R ??

Have you checked battery ?? (Sillly question I know, but people tend to forget the basics)

Have you tried pushing the bike to start her?
 
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#28 ·
All the tests under diagnosis procedure #1 checks out fine. That leads me to diagnosis procedure #2 on page 6-42 i.e MIL CIRCUIT TROUBLESHOOTING, I did ground the White/Blue wire then turn the Ignition ON as instructed in the manual, and the MIL(FI) lit up and the manual suggest to replace the ECM.

Yes..Before fixed, the speedometer and fuel gauge still lit even the ignition key is off..have to disconnect the battery to turned them off, after fixed it gone as usual...

I think the power thru the relay is enough, as it can cranks steadily but wont fire up.

What is R/R?

Battery is healthy. Cranks very fast.

Yes, tried pushed her but to no avail.
 
#30 ·
If you wanna check if its a battery issue without having to actually change the battery you can always jump-start your bike using your car's battery...

I did it more than once on my 03.... It will give the bike the impression that there's a battery and it's full...
 
#31 ·
Well she didnt start this morning :( have the "no fuel pump priming sound" she cranks but does not start. Gauges / lights are ok, i had no time to trouble shoot this morning, took car to work. I'll start the process tonight. Big time glad it happened in my garage vs at work or out riding...
 
#33 ·
Hey Moe i was going to email you back, its all good :) got home from work and simply flicked the Kill Switch a few times and she primed, started right up! guessing it was a loose connection, i will either take apart and clean or just buy a new switch, $35 or so. Was also talking with Parker today, i guess the kill switches on our bikes are notoriously failing from what i hear. I also never use mine, always use key to turn bike off, so i wonder if that played a role at all? in any event im very happy i dont have other issues :) took a few close up pics i can post later if need be.
 
#34 ·
guessing it was a loose connection, i will either take apart and clean or just buy a new switch, $35 or so.
Notorious issue with the 03-06. Also other issue is the "start" switch sticking and staying somewhat depressed, causing headlights not to come on.
 
#38 ·
got some pics of unit, comes as 1 unit (plug and play) part # is 35130-MFJ-D01
and to clarify, the 2 wires i show above are actually for the brake switch my bad, the other main wire coming from switch would have Kswitch and starter, thx to Parker for correcting me there

"In the schematic; the wires the go to the left with the two prongs on the end go to your front break lever switch, the wires that go down and to the right with the plug at the end are for the whole unit (connecting the kill switch, starter button, and brake light switch to the rest of the bike"


 
#39 ·
To add my advice to the forum:

My suggestion to anyone with a kill switch that is intermittently working would be to replace it. It's not too pricey, and will offer some piece of mind.

You could definitely open it and clean it, but you won't know for sure that it will work well for the next wile (a Band-Aid solution if you will). If you are out riding and the kill switch stops working and is "off" even though the switch lever is "on", you would either have to splice the wires on the spot (a sort of hot wire when you have the key) or have the bike towed (which would SUCK). You can't bum start the bike with the kill switch "off". So you are SOL.

IMO replace it.
 
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