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Help my bike wont start/run properly
Help my bike wont start/run properly
Read this to fix any issues with starting or running problems
Published by Despise
Post Help my bike wont start/run properly

I always get people saying my bike wont start and this question seems to come more often than most so this is a simple but in depth guide to [HELP]My bike wont start/run properly. So you have a non running bike for whatever reason, lets help you poor sods out.

(some of the tests below will require you to have spare parts or to go out and buy some.)

Key* for short words

sp = spark plug
ic = ignition coil
ks = killswitch
irk = Inner rota kit
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[How to] Check for spark (For spark plug and ignition coil testing)

Take the sp out of the engine, give the sp abit of sanding with sand paper to clean it up, if the plug is wet dry it 1st. Then put the sp in the ig and put the tip of the sp on something metal, kick the bike over and did you see a spark? If you did thats good.

If you didnt see a spark, look at your ks and unplug it (follow the wire till you find the plug & disconnect). Kick the bike over again, did you get a spark? If you did, then put the sp back in the bike with the ic cap on (leaving the ks unplugged) and kick it over and your bike should run meaning you will need a new ks. To kill the bike once its running, simply pull off the ic cap off the end of the sp.

Stator Testing

Still not running? Get to the stator and smell it, if it smells burnt out the chances are you will need a new stator. To test it use a multi-metre on the igntion side on the blue an green wires and you should get about 100OHMS of resistance. If theres nothing then the stator is dead and If the reading is higher or lower this could be a sign of the stator on its way out. If you know for sure its gone replace the stator.

Another thing to check is that the pickup near the stator is clean.

Still not running? you will want to retry the spark test with another sp (being a sp is cheap).
If the sp is wet when you take it out your best bet is to replace it is fouled & maybe dead. What you may do though is keep it, put it in a dry place and wait a few days for it to day out, then you might be able to use it.

Still no spark? next thing to do is replace the ignition coil and retry the test. After this try another CDI unit
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ok you have spark but the bike wont run.

Carb/sp setup: Take the plug out and what colour is it?

You want your sp perfect aka brown.

Running too rich will cause your sp to be black and this isnt ideal. This is caused by the mixture of air/fuel to be incorrect, the jet is too big or excessive use of the choke. To correct this, find the mixture screw on your carb "INWARDS" (should be clockwise) at roughly 1/2 turn at a time.

Running lean will cause your bike to not run properly when your engine gets hot, this can also lead to sp blistering, melting, engine problems and backfiring. To correct this, find the mixture screw on your carb "OUTWARDS" (should be anti-clockwise) at roughly 1/2 turn at a time.

Still running too rich or too lean?

Then the other option is that the carb needle height is too low or too high, on the needle theres a small eclip witch sets the needle height, by default you should start in the middle.

If its too rich you will want to lower the needle 1 notch at a time (aka move the eclip up) > (while doing a rich/lean test [read below] for each notch/setting) if too lean then you do the oppisite of whats been said above.

If you have done all of these and your still not running properly then you either have the wrong size carb (too big or too small) or the pilot or main jet aint the correct size.

For more info > http://www.ooracing.com/tuningTips.htm#Sparkplug

Rich/Lean Test
When you can get the bike running you will want to take your bike for a run, run it hard for a good few minutes round the block then kill the bike and take the sp out, What colour is it? If the colour is incorrect adjust the carb accordingly above and redo this test. Remember, if the sp is black sand paper inbetween the gap and the top of the sp so its clean then put it back in when your ready to retest.

If the sp is wet either dry it off or replace with another spark plug for the test.

If you still cant get your plug colour to change, you will need to raise or drop the the needle making it richer or leaner. If you get to the end of being able to change it, you will need to change the main jet. For anyone that has put a new carb on, (for anyone not in the know) consider that the carb is too big for the engine.

spark plug Info
List of spark plugs when looking to buy a new one:

NGK Iridium CR7HIX
Torch A7TC
NGK CR8HSA plug for highly turned engines/ hotter plug

Recommended spark plugs are:


stupid things to check

Bent fuel line

Check the carb float aint upside down

Dirt in the carb/blocked jet

choke left on

Check choke is on when warming up engine and off when your ready to ride

killswitch is on or failed

Water in the carb = drain out with the overflow screw

Dirt in the carb = take it apart and clean

Blocked or bent crankcase breather tube

No oil

No fuel

CRAP in the fuel

low on fuel = use the reserve or fill up

low carb idle = turn it up

Mud or water in the exhaust

Symptoms of non running/running problems
(in no real order)
You kick the bike over but only starts now & again = sp/ic/stator/dodgy killswitch

The bike runs but after warming up or going for a ride the bike dies = stator/wet ic/sp running lean

Bike wont run at all = water in the engine/wet sp/dead electrical component, stator & ic being the most common,CDI/fuel/wiring problem/ bad ic earthing to frame

bike wont idle, have to keep the revs on abit = low idle/carb running too rich and wet sp/cold start without using choke 1st

Bike sputters or jumps when riding = **** in the carb or air filter/not enough air/not enough fuel/water in the carb/carb jet size too big (bikes been sitting a year over = possible loss of octane in fuel) or failing Ignition coil

Bike starts/fires up but then dies = carb idle or mixture/stator/fuel/wet sp

Bike woudnt start very easily/stall lots = sp running Lean/clutch not disengaged, may need readjusting/ faulty ig or cdi/ dirty stator

Bike runs sometimes/only sometimes has spark and cuts out = killswitch/any other electrical component ig ect

fuel pours out my overflow tube = overflow screw is loose or carb float needs resetting

Water in your carb? dry out your air filter and undo the bowl overflow screw to flush the carb.

Water in your engine? A few things you can do 1. take the exhaust off 2. take the spark plug out and tilt the bike 3. use a warm room or something hot to heat up the engine and evapourate. Or with the spark plug out and the fuel pipe disconnected kick the bike over a good few time to pump it out.

High revs/idle = kinked throttle cable, throttle sticking, slide inside carb sticking, air screw over turned clockwise.

Bike starts fine but once hot bike cuts out or wont restart till cooled down = 2 likest causes, ic or stator

Bike runs but bike pops or exhaust is glowing red = check valve/tappet clearances. carb mixture is running lean
VALVE check video > http://www.pitbikeclub.co.uk/showthread.php?t=7003

Still not running?
If you have followed this thread down to the last word and your still not running then all I can suggest is to re-adjust your tappets (especially on stomps with IRK) and check your loom wiring and connections.

Note: I will add to this list at a later date
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