cbr250 rr no spark

[damien]

hi

my partner (beece) went to set off on her usual saturday morning ride last week and the bike would not start, was cranking over as per normal, tried with and without the choke and all the other usual tricks (and checked kill switch and there is fuel and its turned on) but it just kept cranking the started coughing little flames out the exhaust,

i recharged the battery

then inspected the spark plugs and there is no spark there, so i replaced them and it made a very minor difference, there is a very fine spark that only lasts for the first couple of seconds of cranking,

any ideas, there doesnt seem to be much to the ignition system on these bikes so im wondering if there is a common part that stops? before i start replacing everything

cheers damien

[Frogger]

if all the plugs are not getting spark my guess is the battery has dropped a cell . this would mean it doesnt have the power to turn the stator and produce spark. if u have a multimeter stick it on the battery and when u crank the bike if it show's lower then 9v even for a second it normaly means its dropped a cell. if the battery isnt that old get it checked at a shop to double check.

[Cbr Junkie]

I doubt if the battery had dropped a cell that it would be able to crank.

[Loud]

The battery turns the starter motor, which turns the crank, which turns the stator which powers the bike and coil and recharges the battery. If the bike is turning over fine then it's something else.

So not one of the four plugs were firing? If it was a car I'd be looking at the coil, HT lead and distributor cap. If it's got four coils then I'd be squinting at your ignition module in a suspicious manner.

Is it definitely a weak spark? And on each plug?

[Frogger]

sorry i ment startor as in the starter motor, i had this same problem on my zxr250 would turn and then back fire after abit , turned out the battery had lost a cell and didnt have the power to turn the startor motor and give a strong spark.

[darkfibre]

Just remember on a 4 cylinder with 2 coils, the spark is actually generated between the 2 plug leads of each coil.

Each coil has to jump 2 plugs at the same time. To properly test for spark it is between the two leads on each coil, not at a 'single' plug.

Looking at a run up of a GSX750 set up to give you an idea;
http://www.youtube.com/watch?v=lvHuHutHvVM

Just imagine each lead connected to a plug, and each plug joined by a connection (cylinder head in real life).

If any one lead or plug has a fault, it will effect the whole circuit.


Clear as mud?

[Loud]

Cool, I've learnt something, thanks DF!

[damien]

ok so i have replaced the battery and plugs
checked fuses and still no spark,

also i used to buy all the parts for this bike from klem nunn as they have closed down were is the best place to go now???

[quadeyquade]

Its a cbr250rr, its going to be the regulator rectifier

[fredie]

buy 1 from the wreckers . probly cheaper

[darkfibre]

Its a cbr250rr, its going to be the regulator rectifier

The reg controls the charging system, this seems to be a no spark when cranking problem.

A quick look at a wiring diagram shows that there are a few easy tests to help pinpoint the problem. Do you have a multimeter and happy to get your hands dirty?

Should be straight forward to diagnose the correct component without guessing with a few tests.

[damien]

The reg controls the charging system, this seems to be a no spark when cranking problem.

A quick look at a wiring diagram shows that there are a few easy tests to help pinpoint the problem. Do you have a multimeter and happy to get your hands dirty?

Should be straight forward to diagnose the correct component without guessing with a few tests.

yep will confirm its not the regulator rectifier

have got the wiring diagram myself and started looking at things...

i have since found that the SPARK UNIT located next to the battery seems to be having a drama. the 30a fuse is blown and once i disconnected the plug it seems there has been some arking out going on, the plug is a bit melted and burnt

any answers to were to buy parts for bikes???

thanks darkfibre for your help

[fredie]

what year model cbr250rr

[darkfibre]

What color wires show the arcing?

Also have a look inside the TCI unit and see if any of the transistors look burnt or hot..

[Pinkee]

if its your coils or ht leads, then i have a working set that you can use to test if thats the problem. just pulled them too. my 30A was melted like a mofo too, but still worked.

[damien]

if its your coils or ht leads, then i have a working set that you can use to test if thats the problem. just pulled them too. my 30A was melted like a mofo too, but still worked.

thanks ill keep the offer in mind, as far as i can see the burn wire is a solid RED one.

[DrShan]

Interesting... thinking maybe a CBR 250 isn't such a good choice for me first bike..

[Stavtech]

lol, i think youll find a lot of 20 year old bike develop some issues. even newer bikes out of the factory have problems e.g hyos and duc's etc

[Frogger]

yes but a hyosung will cost you half the price and has a warrenty.

[Stavtech]

Thetes a reason why they cost half the price!