Author Topic: RM125 Ignitions  (Read 3913 times)

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Montynut

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RM125 Ignitions
« on: April 12, 2013, 01:18:17 am »
Can anyone tell me if the CDI box, and magneto complete from an RM125N/T fits an RM125B/C? Is there any later models that fit onto an RM125B?

Has anyone fitted an aftermarket ignition to the RM/B?

Offline SON

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Re: RM125 Ignitions
« Reply #1 on: April 12, 2013, 04:11:56 am »
Greg call me at work

TM BILL

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Re: RM125 Ignitions
« Reply #2 on: April 12, 2013, 05:47:13 am »
Can i ask whats wrong with the original units , I may have an N or T set up and a bit of time this morning , will see if i can try it and report back  :)

Offline Lozza

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Re: RM125 Ignitions
« Reply #3 on: April 12, 2013, 07:03:23 am »
Can anyone tell me if the CDI box, and magneto complete from an RM125N/T fits an RM125B/C? Is there any later models that fit onto an RM125B?

Has anyone fitted an aftermarket ignition to the RM/B?

Late model DC/DC ignitions are vastly superior to old high voltage ignitions, can be adapted ignition by machining a sleeve for the crank taper. Late model CR 250 is a good one to adapt. With the cheap LiPo batteries($86 delivered) that weigh less than the box they come in and can run at any orientation, running total loss the new fully programmable ignitions are hard to go past. 
Jesus only loves two strokes

TM BILL

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Re: RM125 Ignitions
« Reply #4 on: April 12, 2013, 09:21:11 am »
Just fitted the ignition off an RM 250 N ( i dont have an RM 125N set up ) to an RM 125B and it physicly fits . Will try to run it later and report on Timing / performance .

Montynut

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Re: RM125 Ignitions
« Reply #5 on: April 12, 2013, 06:49:53 pm »
Can i ask whats wrong with the original units , I may have an N or T set up and a bit of time this morning , will see if i can try it and report back  :)
Bill,
My bike ran perfectly for two races then gave all indications that a plug had failed. Replaced that but still the same it just misses then dies under load. Runs for a little while when started from cool.

It looks like a CDI unit but they are all approaching 40y.o. so even a good one is questionable. I am not sure that spending money on the xisting one is worthwhile. Was just drawing on the brain trust here to see if a 1995-200? one fits on.

I may look at a new type system but a lot of money.

Offline xl59

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Re: RM125 Ignitions
« Reply #6 on: April 12, 2013, 09:35:17 pm »
Hey GREG,my advice sell all smelly twostrokes and buy ya work of the devil back,HA HA Cheers GREG

Offline Ted

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Re: RM125 Ignitions
« Reply #7 on: April 12, 2013, 09:40:17 pm »
It probably failed cause your arse is too big for the seat. You are not still seventeen Gregory :o


Year 2000 electrics permissible on a Pre 78 but not 1976 swingarms ..I smell a rat ::)
« Last Edit: April 12, 2013, 10:11:20 pm by Ted »
81 YZ 465 H   77 RM 125 B

Montynut

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Re: RM125 Ignitions
« Reply #8 on: April 12, 2013, 11:41:25 pm »
It probably failed cause your arse is too big for the seat. You are not still seventeen Gregory :o


Year 2000 electrics permissible on a Pre 78 but not 1976 swingarms ..I smell a rat ::)

Well the 2000 electrics actually existed Ted while the phantom optional alloy swingarm is just a myth printed in the parts manual as joke by an unhappy worker at Suzuki in 1976 ;D

Greg H I would rather push my two stroke while making ring ding sounds than consider buying the parts required to do a basic top end freshen up on a bloody 4 stroke ever again. I mean the gasket kit alone requires a box trailer to bring home with more gaskets, 'O' rings etc than in the space shuttle. The other thing is the power ::) ::) or more exactly the total absence there of. The little 2 st with me making the ring ding sounds still roosts those 2V XR200  ::) :P :P :P :P ;D ;D ;D ;D ;D ;D ;D ;D ;D

Montynut

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Re: RM125 Ignitions
« Reply #9 on: April 12, 2013, 11:47:24 pm »
Oh yeh you two (Ted & xl59) great that you contributed but umm how do I say this  umm Oh yes   PISS   OFF with your Tom foolery this is serious :P ;D ;D ;D

Offline Ted

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Re: RM125 Ignitions
« Reply #10 on: April 13, 2013, 09:27:28 am »
Always a pleasure to be of assistance. Feel free to burden me with your woes anytime ;D

Here's a thought , Why don't you port the shit out of it with those specs I SO KINDLY gave you and if you ever get it running ( you know, within the spirit of the era, of course ) it will go like a scalded cat. Something to ponder. Have a nice day
81 YZ 465 H   77 RM 125 B

oldfart

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Re: RM125 Ignitions
« Reply #11 on: April 13, 2013, 07:27:16 pm »
Spent most the day sorting my Rm 125 T ignition wooes  so I thought I would
post my out come.
Bought this bike about 12months ago, the previous owner said you had to push start it to make it run  ??? 
Any way I decided this bike was  in need of a total rebuild and I would have the stators rewound / buy a new coil  and I had a spare CDi unit so I thought I had it covered, 12 months on
So today all I needed to do was put fuel in it give her a few kicks  and away we go ......Wrong   ::)
Ok we have spark and fuel   kick kick and many more kicks .... no luck
replace coil  ....  no not that  ..... replace carb - no luck either ... Replace cdi - still no luck  ...
I don't have a spare Rm 125 T  stator to try ..... but I have spark and it has been rewound, So I assumed it is ok
Ok push it and it starts ... Wtf   but it won't rev.

Time for a cuppa as I'm now at wits end to what it can be ?????

Remember this bike has had many owners so anthing is possible....
So I pull the mag cover off my Rm 125 B  and notice the coils are in different positions .. Ie small on top and large on bottom , where as mine are the other way round.
Time  out to look at  tech books and another cuppa .... yep swap them around
 around.
Kick kick      ring ding ding ding     give it a bit of thottle riiiiinnnng ding ding ....... you ripper.

Conclusion.... at some stage someone has had the coils re- wound and  forgotten which order they come out     


 


 

Montynut

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Re: RM125 Ignitions
« Reply #12 on: April 13, 2013, 07:51:14 pm »
Fiddled with my 'B' ignition today. Checked all connections and cables for continuity all OK, checked all earths and mounting screws all clean and good continuity. Installed the CDI off a T model but still no go.

The bike came with a MotoTek ignition module so put that on temporarily and started straight up and ran normally. This proved the stator. I am now suspecting the HT coil. I used a generic coil designed for CDIs from the local bike shop. It tests OK with a multimeter but I don't really have any reference values.

Montynut

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Re: RM125 Ignitions
« Reply #13 on: April 14, 2013, 01:59:01 pm »

Montynut

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Re: RM125 Ignitions
« Reply #14 on: April 14, 2013, 06:40:56 pm »
Problem solved  :-[ the old broken wire inside the insulation. Tested it 3000 times OK tested 3001st time while pulling wires BINGO

Bugga

The classical 6cent part story :-[ :-X