TM 125 ignition woes

[ty4]

where to start, the bike had a dead CDI unit when i got it so i replaced it with an unknown suzuki unit ( the sticker was rubbed off).
couple of kicks and away we go..actually sounds quite good...then it went down hill quick with the sound of a plug fouling..simple fix, new plug...what i have now is a bike that kicks back at very slow kicking speed and wont fire at all at normal kicking speed.... WTF

checked the flywheel key and the usual stuff...there is a bit of movement in the l/h main but not that bad....i can't have had two 40 year old bikes in a row enter the shed with bad pulser coils.........................can i ??

tony

[brent j]

Do you know anything of the history of the bike?

I suggest finding a TM125 CDI as I believe different models have differing ignition curves. I ran a TS185 CDI on mine and it ran ok down low but didn't want to rev

I had kick back dramas with mine and it wouldn't run right. It turned out it was a Honda piston I was using which was giving too much compression. It would run with the ignition retarded but these bikes seem to have fairly weak kick start gears and I ended up replacing two of them. And Suzuki in their infinite wisdom put the kick start gears inside the main cases

Is the ignition backing plate in the centre of the adjusting slots?
I sent my complete ignition to Betta-bikes and had it tested. It came back ok and at least (in my case) gave me another direction to look

[Doc]

Tony, check the wiring insulation isn't cracked or wires bared somewhere in the loom..sounds to me like it maybe an earthing issue. Disconnect the kill switch will also eliminate a problem there and make sure the ignition coil is well grounded to the frame.

[Slakewell]

Why do you guys put up with electics that are 40 years old and still expect them to work like new. Put a new PVL on it, as little as $200 on ebay, get a proformance gain and watch the other guys in the pits pushing there bikes.

[Doc]

Slackwell..can you direct me to the seller of the $200 pvl ignitions?

[brent j]

Slackwell..can you direct me to the seller of the $200 pvl ignitions?

All the ones I found were $4-500, keen on $200 though

[Slakewell]

There out there on ebay , They do come with the need to bore the flywheel yourself. Another forum member put me onto a seller who has them. I look back thou my ebay history when I get a chance.

[ty4]

thanks guys.. i just put a new piston and rings in it ..non genuine and it does have good comp for a 125..tried all  the way from centre of backing plate holes to full retard...no differance...Oh and i know nothing of the history of the bike , other than it was cheap and every thing needs repair

all the basics are already done Doc..thinking of replacing the wires down to the coils..but they test OK

almost every bike that has entered my shed has had a 30 to 40 year old ignition and worked fine ..wether points or CDI..guess the odds have caught up with me

thanks again

tony

[Slakewell]

http://www.ebay.com.au/usr/dmon-parts?_trksid=p3984.m1439.l2754

[ty4]

at $726.55 i think i'll pass

[oldfart]

Open at top of page ....items forsale 

[Doc]

http://www.ebay.com.au/itm/PVL-Ignition-3-Race-Ignition-Honda-KTM-universal-MX-Racing-Speedway-Yamaha/300607628905?_trksid=p2046732.m2060&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D27%26meid%3D5289009776305878068%26pid%3D100040%26prg%3D1011%26rk%3D1%26rkt%3D4%26sd%3D300607628905%26

mmmm..would need an adapter plate and rotor taper machined but still not a bad price.

Can't speak for others but personally I've rarely had an issue with the stock originals 

[Lozza]

The ignition curve in that CDI  is complete shit, it only has +3 deg then only -2deg.

http://www.ebay.com/itm/Yamaha-YZ80-YZ-80-IGNITION-COIL-CDI-WIRING-STATOR-FLY-WHEEL-93-95-96-97-98-99-01-/161239064350?pt=Motorcycles_Parts_Accessories&hash=item258a98df1e&vxp=mtr

http://www.ebay.com/itm/2003-Yamaha-YZ85-YZ-80-IGNITION-COIL-CDI-WIRING-STATOR-FLY-WHEEL-93-98-99-01-/171251382514?pt=Motorcycles_Parts_Accessories&hash=item27df60b8f2&vxp=mtr

Much better and cheaper option.

[brent j]

One of my TM125 motors has a YZ80J ignition fittted.

It required some work, an adaptor plate to take up the difference in diameter and I had to bore the taper in the rotor to suit the Suzuki crank. it's an iternal rotor type like the TM rather than the one's in Lozza's post.

The bike starts very easily, idles smoothly and runs fine into the mid range. It looks like it needs some jetting adjustments but I'm having trouble finding the time to do it.

And the ignition came courtesy of Lozza, thank you

[Lozza]

No problems Brent  Everyone moved away from internal rotors to generate more Watts for the ignition. The J ignition made really good HP on anything it was fitted on.