honda nsr 125 starting problems

[DANNYBOI]

my nsr engine cranks over all day but will not fire up getting good spark br9ecs spark plug could this be ecu related? the kill switch dosent seem to do anything either
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NSR YEHA

[lihp]

If you're getting a spark, the only things to check is that you're getting air and fuel, check fuel lines and fuel tap etc.

Then if all those appear good, are you getting the spark at the right time?

[slyrob]

definitely check your kill switch wiring as iirc my NSR cranked over with the kill switch off without starting, worth checking the choke cable as well.
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Pitslayer wrote "it could be Ndubz.....ruining this once great place with donkey gobbling loafer knobbing "music".
silky666 wrote "In my eyes, when you shake cocks with the devil, you may as well go for the full reach around"
Villers wrote "as reliable as a ginger stepchild on smack"

[DANNYBOI]

getting good spark fuel line and filter checked there fine the airbox ect is all secure the only thing i can think is a fueling issue the stand switch is not connected as the engine is out of the bike would that make i difference?
cranks fine but dosent seem to fire its annoying as its just a coil if it was a distributor i would be fine lol
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NSR YEHA

[DANNYBOI]

slyrob whats iirc?
killswitch is wired up dosent seem to make a difference when turned on or off just keeps cranking
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NSR YEHA

[Lynxx]

could be a blocked jet or reeds stuck ? try cleaning the carbs and checking the reeds. does the spark plug get wet after cranking it over and if so, is there any water or is it just fuel ? if its not wet its deffinatly a carb, reed or fuel problem.

just to add, does it have good compression? try cranking it over while putting your hand on the back of the carb, it might start and if it doesnt it should suck on your hand in pulses. if the suction is weak then it appears you may have a bad set of rings, base gasket, crank cases are leaking or the cylinder is scored or cracked badly. it should suck even when theres not a spark plug or cylinder head on, if the bore is bolted down.

[Handsome]

Had that issue with mine once, gave a good spark but wouldn't ignite the minute I put the plug back in the engine, tried three other new plugs before I got one that did it, try a new plug, you're only looking at what, a pound or so each, also comes in handy to have a couple under the seat...

Never had a days problem with mine until I had to have the top end done, was never right after that, in the last eight or so months I had it I must have gone through a good twenty plugs and six batteries...
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Previous Bikes...Honda NSR 125 RR...Kawasaki Zephyr 550...Suzuki SV 1000 S...Yamaha FZ8...Current Bike...Suzuki GSX-R 750...

[lihp]

try dropping a little fuel down the carb or, some easy start. If it starts fine, then you have an issue with the fuel delivery somewhere between the tank and the venturi If it doesn't work, you have an ignition issue.

[Handsome]

After reading Phils reply above regards fuel delivery, another one that caught me out more than once was kinking the fuel line after having the tank up...
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Previous Bikes...Honda NSR 125 RR...Kawasaki Zephyr 550...Suzuki SV 1000 S...Yamaha FZ8...Current Bike...Suzuki GSX-R 750...

[alains]

check diodes (or replace)
https://www.geneva-racing.ch/~alains/loomdiodes.jpg
https://www.geneva-racing.ch/~alains/diodes.jpg
the other possibility is a worn CDI unit
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the worst day fishing is better than the best day working

[DANNYBOI]

battery reads 13 volts should be enuf for it
fuel entering
have x2 sets of diodes what are they supposed to read?
new plug
gonna get new fuel tomorow hopfuly that will do
sny chance it could be piston rings?
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NSR YEHA

[lihp]

Did you try what I suggested? You'll find it far cheaper to identify the system at fault before going out replacing parts.

[alains]

about diodes , you cannot check them , just replace (you need to open the loom by cutting the tape)
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the worst day fishing is better than the best day working

[GSTEEL32]

compression. air leak.