rs125 nostartin

[andy 13]

Hey all can sme 1 help please am having problems with ma rs125 1998.
it just wnt start my coil is working great cdi unit brand new getting a great spark and ma battery is brand new aswell, and still nothing any sujestions would b much appreciated.
thanks andy

[.....]

Is it getting fuel?

[andy 13]

[HD]

Have you checked properly?

Drain your carb, clean your fuel filter, maybe the air filter too.
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Rusty '02 Vito Camper + CBR600F3

[andy 13]

[Syris the Indomitable]

Is the plug wet through?
You could be way to rich.

If not check behind the dash and see if you got one these playing havock.
https://img202.imageshack.us/img202/1871/meninblackalien.jpg
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In Greek mythology Ichor is what immortals have in the place of blood
Those that mind, don't matter...Those that matter, don't mind. Do you agree with this?

[Kickstart]

Hi

Can you bump start it?

Helped someone with an RS125 once which would bump start but not start on the starter motor. Taking the plug out gave a decent spark.

Problem turned out to be the clearance between the crankshaft position sensor and the flywheel which was WELL over that specified. On the starter motor with the plug in place it wouldn't spin over fast enough to trigger the ignition. With the plug out it would spin over more quickly and so spark.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[andy 13]

[andy 13]

[Syris the Indomitable]

[andy 13]

[2Smoke]

Hi, you could have a flooded engine.. Try turning the fuel off, taking the plug out, putting it in gear and pushing it along for a bit to clear any fuel from the crankcases. Leave it for half an hour, go for a beer smoke whatever. Dry the plug out (heating it works well too). re-fit it, and see if it'll start.

Other possibilities are:

Crank seal popped out, can happen if there is excess fuel in the cases and it ignites.

Bad fuel (could be worth trying some fresh stuff)

Ignition timing out (woodruff key sheared and flywheel rotated on the taper)

Lack of compression through damaged bore/piston. Spin the motor over with the plug out, stick your thumb over the plug hole and see how much force there is.

Water contamination, maybe headgasket failure or through water in the fuel.

Have you tried draining the carb?

Did it just suddenly stop running or has it been sat for a while?
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Currently in the stable.. '89 TDR250, 86 NSR250 '79 350LC, '79 DT175MX, 82, Pasola, '98 R1, '95 Speed Triple.. all of them total sheds..

[andy 13]

[Syris the Indomitable]

I think this is a case for M&S https://img714.imageshack.us/img714/4993/76358856.jpg

Not messed with the jets or needle height at all have you?

The standard main jet on a 28mm carb is a 120, so id be buying a 122 and 124 to start off and see how you go.
The main jet only controls the third 60 - 100% of your throttle therefore, you will need to adjust the needle jet for the rest of the throttle 35 - 60%.

Other than that all you need is a Deloroto VHSB 34MM
____________________
In Greek mythology Ichor is what immortals have in the place of blood
Those that mind, don't matter...Those that matter, don't mind. Do you agree with this?

[2Smoke]

Well the main jet does have an influence on the running throughout the throttle range, but I dont think this is the problem.

Andy, have you taken the exhaust off at all and looked up the exhaust port at the piston? Be worth looking for signs of a partial seizure.
____________________
Currently in the stable.. '89 TDR250, 86 NSR250 '79 350LC, '79 DT175MX, 82, Pasola, '98 R1, '95 Speed Triple.. all of them total sheds..

[Kickstart]

[andy 13]

[Kickstart]

Hi

Not that high. Normally with a carb problem (unless very major) I would expect it to be startable with a bit of effort, even if it runs like a dog.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[andy 13]