missfiring electrical issue,lights affect revs

[tonydevon]

ok so having spent time and money on jetting and sodding about trying to get my scooter to rev I have found an odd problem

depsite multiple jet setups it just wont rev.

I put the strobe on it when it was first built andfired up to check timing.

today I was trying to work out how to put the lights on as i had no idea if they even worked,yup Ima total newbie

it ran a tiny bit better with the lights fully on???? held the engine at its stuttering point and you could hear it change note, rev slightly higher as the lights were turned on???

connected strobe backup and tried to rev it up, it goes flat like normal, but strobe cuts out

so Im thinking that Im losing the spark as its revved up.

what could be the issue? I have replaced HT lead,changed plug and cap.

its got a blue CDI coil thing,

anyone got any ideas, or is it a buy and swap bits about job?

[rosscla]

You should check the impedance readings on all the connections at the stator with a multimeter ( do a search for ohms to get the readings) tape the coils with a screw driver to see if they change which could indicate a vibration issue. If they're ok then try swapping the CDI with a a known good one off a running bike.

If that doesn't solve it then you're looking either the LT coil or the pick up / flywheel. It's not unknown for the LT coil readings to be ok but the unit to be faulty and there are some flywheels which are incorrectly marked or machined.

[tonydevon]

ok thanks,thats an idea,something to get me started, will look for the coil resistance figures for the stator and see how it goes

will order a cdi coil thing anyway,most places it takes a week to deliver, and I dont know anyone with one.

was thinking of ordering a bgm stator,now maybe I got no choice anyway.

annoying as I know the lad that owned it previous purchased it all new not long before it died, done about 80 miles.

[tonydevon]

well sort of good news,sort of not LOL

white to earth is 0 ohm as should be
white to red is 93 ohm, close to the 95-120 spec
white green is 452 ohm, within the 450-540 ohm

order new cdi,might get regulator as well.

did have a thought, my garage is regularly used for welding and grinding, I did clean off a lot of filings from the magnets in the flywheel,could it be that theres still some rogue filings in there messing it up??

surely though the pickup works at low revs,so should be ok??

will whip it off again tomoro and have another look at it.

it has to be electrical as I have been right through the range of jetting and its the samewith all of them

[blue]

Could be your ignition switch, try it with the green wire from your loom to cdi disconnected.

[rosscla]

Get a decent CDI from a reputable source, most will do next day. It shouldn't be the regulator as this is properly only concerned with supplying power to the lights etc.

I'd also be checking for anything that could cause arcing inside the stator.

It's also worth removing the green wire to the loom from the cdi to eliminate switch / shorting issues in the loom or ignition switch.

[tonydevon]

ah ok thanks will look into that green wire.

I assume that to stop the engine I will need to reconnect it and turn key off?

had a look at the wiring loom, is it really that simple, ie lose my key, just unplug the green wire and ride off LOL

maybe vibration or something is earthing it, good call, especially as it appears to do strange things whenI use the key to turn lights on and off

cant start it up now as its too late,but going to try and mess about, rig up DVM to test continuity on green loom to earth, see if wiggling things will earth it with ignition on

[tonydevon]

ok thanks will order one of them as well, what the hell.

if its not that then I have a spare

I dont know what revs but its getting to about 3k maybe, not much above idle, should have twigged it was ignition much earlier.

is there much mileage inbuying a BGM pickup, 4x the price of a K2,are they better?

[joeswoonara]

WHOA !! DONT try to reconnect the green wire just grab the brake and stall it you`ll get a right pissser!!

[Yanker]

Get a decent CDI from a reputable source, most will do next day. It shouldn't be the regulator as this is properly only concerned with supplying power to the lights etc.

I'd also be checking for anything that could cause arcing inside the stator.

It's also worth removing the green wire to the loom from the cdi to eliminate switch / shorting issues in the loom or ignition switch.

Agree 100% with the above. Looking for poss. poor earth on the ignition side, and arcing to the Lighting side that is earthing when the lights are switched on