NSR 125R Starting issue

[vlf]

Hey,

I'm having problems starting up my 1998 NSR 125R, the starter motor started failing one or two months ago. It used to take two, or maybe three, times to make it start correctly, but suddenly it just stopped working(or more like making the bike start).

It does bump starts fine, which gives me the idea that the problem lies on the starter motor, thing is, I'm pretty clueless. Whenever I press the button the motor seems to "swirl" and makes some weird noises. What could it be?

Also, IF it's something simple, I'd like to know where the starter motor is REALLY located.

Thanks in advance!

[Scotsman37]

The sounds that you're hearing could actually mean that your start motor is actually working, but you're spark plug is just giving to weak a spark to ignite the fuel already in the chamber. So have you tried replacing the spark plug as yet? Also, when was the last time you checked the voltage of the bike's battery and I would now give it a reacharge to see if that helps if it's currently reading below 10volts.

[mchaggis]

It does sound a bit like a low battery to me. Try taking the battery out and giving it a good charge to see if it's that. If you have a multimeter, check the voltage across the battery, I can't remember what it should be just at rest, but it when revving, it should go up to 14V.

When removing the battery, remove the negative first, then the positive.

When putting it back, connect with the positive first, and then the negative.

I'm lead to believe that charging the battery without removing it from the bike is a bad idea.
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[vlf]

I haven't tried anything concerning spark plugs since I don't even know where they are and how I can see that they're worn out. I'm prettly clueless in terms of mechanics.

And about the battery, I was told that it wasn't it's fault since it's quite new and plus the lights are very strong, they show no sign of fluttering. I've ridden it a couple of times after the incident with the starter motor and it would probably have recharged enough? I mean, if it really was the battery or if it wasn't recharging then the lights would start to weaken, right?

[Scotsman37]

Firstly, buy a Haynes manual for your bike as it will guide you in how to do maintenance on your bike.

To find the spark plug is easy because it situated at either the top left/right side of the engine, of course, but if someone on here already owns one or has in the past they can tell you exactly where it is. There is an L shaped plug which fits onto it which you pull upwards to remove it to get access at the spark plug.

To remove the spark you need to use the standard toolkit supplied with your bike and, if not, then you need to buy a spark plug removing tool which matches the size of the spark plug that's installed in your bike. You should get that tool and the spark plug from your nearest Honda bike dealers as they will sell the correct one for doing that job

[vlf]

Hmm pardon my doubts but wouldn't the bike not work at all if the spark plug wasn't working? It does start and runs well when bump started. Wouldn't it be eletrical?

Also, I've checked the battery. It shows fine values.

Thanks for the help so far!

[Scotsman37]

With a weak spark plug you would need to bump start it to help it move the pistons because it requires a spark strong enough to ignite the fuel as to move a piston from stand still.

[vlf]

I'm getting some sense out of it. As a last question, would the engine still be mute even if the spark wasn't strong enough to start the engine? Wouldn't the spark even make some noise?

Thanks a lot, I'll buy a spark plug and the tool to remove the old spark plug. Even if that's not the problem, I'll have to change it, eventually.

[Scotsman37]

If the spark is so weak or not even working then the fuel will not ignite to move the piston ie no noise!

Also, spark plugs only last for so long......until the day they need replacing!

[bish777]

if youve got a weak spark, he thing wont start off the starter, but after a few minutes of cranking youll get an allmighty bang out of the exhaust lol.

[alains]

here is your starter
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[vlf]

Thanks for the diagram alains!

By the way, I just found out my spark should be a platinum spark and is very new(less than 1500miles), does this make this still make the spark the culprit?

[alains]

it's certainly a good plug , but i prefer very much the irridium's . you will save about 1/2 to 3/4 L of petrol by full tank . i sue BR9EIX mid-automn to mid-spring and otherwise BR10EIX . i recommand to fit the BR10 if you drive mostly on motorways . they are avaiable at https://www.sparkplugs.co.uk cost £6.84 ex VAT . normally i order 2 of each . time life of those is 4000 to 6000 miles
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[Scotsman37]

Still possible because I remember when I had 125 from new and the spark plug failed within a year.

Here's the type that fits your bike, NGK part no. BRC9ECS;

NGK https://www.ngk.com/results_cross.asp?pid=BR9ECS&x=42&y=8

M&P sells it and matching plug caps too if you ever need them;

Once your there choose 'Click for search', first choose you bike and once done goto the top part of the page and click on the down for 'Item'. You'll find spark plug there.

www.mandp.co.uk

No doubt it will be a lot quicker going to Halfords to buy it (look for the motorcycle section because they don't group all the spark plugs together for some reason?) or your Honda bike dealer instead.

[Scotsman37]

There's also an alternative to NGK spark plugs and they are Spitfire spark plugs that have a 'V' style split supposedly giving a full proof spark to eliminate the possibility of misfire!

I haven't tried them personally but my father put a set in his car and surprisingly it quietened his engine quite a bit indeed because you could hardly hear noise of the engine while driving along in the car. On the plus side his fuel efficiency improved too.

Spitfite spark plug matching service to your vehicle via their link;

https://www.splitfire.com/catalog/index.html

Spitfire has got a good photo gallery from a recent Auto Show Collection; https://www.splitfire.com/autoshow_gallery.html

[vlf]

Thanks a lot guys. I'll see if they ship those plugs over here, if not I better find some random honda dealer and buy a new plug. Or I'll just ask a garage to change/order it because I don't have the earlier mentioned tool.

I didn't think the problem could lie in the spark plugs, but I hope that's the end of it. I'm still not sure though.

[alains]

under your seat you've got a user's tool box . if you have not goto https://www.davidsilverspares.co.uk
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[Dom_]

You say you hear the starter motor whirling around, but is it actually making the engine turn over??

The starter could be fooked.