Replacing 1974 RD350 ignition system with RD400E ignition system

[elram]

Fellow Riders,

Could someone please let me know if 1974 RD350 ignition system can be replaced with RD400E (2R8/2R9) ignition system (stator plate, magnet, CDI and ignition coil)

Thanks in advance.

[RDJames]

plus crank, loom and more

[betty foRD]

As David implies … Pretty much the whole electrical system… including ignition switch , kill switch…

[elram]

Thanks a lot for your input RD James and betty ford.

RD James, please let me know if the tapper of the crank end of RD350 and RD400E are not same.

Thanks a lot.

[5port]

Hi,
The taper is different.  Dave and Betty are right, there is a whole load of differences.  You could do it but there are many changes. Here is my list!
Crank. 2R8 needed or Frankenstein with 2R8 left web and taper.
Crankcase. Stator pin needs removed and CDI stator mount holes need drilling.  "F" timing mark needs making.
Left case cover needs hole or extension welding for CDI trigger coil.
Frame needs mount welding on for CDI box.
Special electric loom for generating circuits and CDI wiring.
Reg/rectifier.
Ignition coil and mount.
Ignition switch.
Kill switch.

I don't think I know of anyone doing it properly.

5port   

[elram]

Hi,
The taper is different.  Dave and Betty are right, there is a whole load of differences.  You could do it but there are many changes. Here is my list!
Crank. 2R8 needed or Frankenstein with 2R8 left web and taper.
Crankcase. Stator pin needs removed and CDI stator mount holes need drilling.  "F" timing mark needs making.
Left case cover needs hole or extension welding for CDI trigger coil.
Frame needs mount welding on for CDI box.
Special electric loom for generating circuits and CDI wiring.
Reg/rectifier.
Ignition coil and mount.
Ignition switch.
Kill switch.

I don't think I know of anyone doing it properly.


5port

Hi 5port,

Thanks a lot for your input.

Could you please let me know why the ignition switch and the kill switch needs replacing?

I will give it a try and report the outcome.

Thanks a lot.

[5port]

Hi,
The taper is different.  Dave and Betty are right, there is a whole load of differences.  You could do it but there are many changes. Here is my list!
Crank. 2R8 needed or Frankenstein with 2R8 left web and taper.
Crankcase. Stator pin needs removed and CDI stator mount holes need drilling.  "F" timing mark needs making.
Left case cover needs hole or extension welding for CDI trigger coil.
Frame needs mount welding on for CDI box.
Special electric loom for generating circuits and CDI wiring.
Reg/rectifier.
Ignition coil and mount.
Ignition switch.
Kill switch.

I don't think I know of anyone doing it properly.


5port

Hi 5port,

Thanks a lot for your input.

Could you please let me know why the ignition switch and the kill switch needs replacing?

I will give it a try and report the outcome.

Thanks a lot.

Hi,

Because the CDI Ignition circuit is different to the Points circuits.  The Points circuits are "made" by the kill switch and the Ignition switch to complete the LT circuit and make it live to work.
The CDI system is self generating and the CDI wiring to the different CDI Ignition switch and CDI Kill switch act as earth paths to kill the CDI LT.  That means the wiring and switching functions of the ignition and kill switch are different between the two types, which means you need the different switches and a bespoke wiring loom, unless you are a god with sparks.
Overall, this could be done, but I have not done it.
Try reading-up and working-out the wiring diagrams first, because you are going to need to!  Also, the engineering of the CDI to the cases may need welding and machining, I am not certain that the bosses are even there on the points cases, although the CDI bikes have the earlier undrilled bosses still on them, the earlier bikes had no idea that the CDI would come along!

5port

       

[elram]

Hi 5port,

Thanks a lot for the detailed information.

After going through the information that you have shared, I am fairly confident that I can try this conversion.

One more clarification regarding the crank end taper difference.
Instead of replacing the RD350 AC left crank web with 2R8 left crank web, can I replace the tapered center of 2R8 magnet (The keyed sleeve) with a magnet center that matched air cooled RD350. I was informed that the Yamaha RX100/RXS magnet center has same taper as the air cooled RD350.

Thanks a lot for you time.

[chrisg.007]

If you want to move away from points, isnt there a specific system for your bike?

[elram]

If you want to move away from points, isnt there a specific system for your bike?

Hi Chrisg.007,

Yes, there are few options available in the market.

I am running CDI in two of my RDs (1973 and 1975) that is designed and manufactured in India, goes by the name "APS ignition system" It works flawlessly and I am happy with it.

I am fascinated to try 2R8 ignition system in an air cooled RD 350 as that is factory fitted.

Thanks a lot.

[betty foRD]

If you were building a project up from scratch… it’s relatively easy to incorporate the cdi ignition… as essentially you just build E/F electrics onto the earlier bike. The E/F is also a better crank … no lead weights to come loose etc..

[Gr8uncleal]

#elram

If you do decide to go for it, then maybe photograph and document your progress, for a feature in future edition(s) of WellaRD. 

[elram]

Hi betty foRD,

The build is completed few months back. Hence, I will try to modify 2R8 magneto.

Gr8uncleal,

Yes, I will do that.

[betty foRD]

Hi betty foRD,

The build is completed few months back. Hence, I will try to modify 2R8 magneto.

You can’t do that as you need the end of the crank to be longer… the tapered shaft is TOTALLY different… just no way to adequately use the existing crank and cdi E/F rotor

[GAZZATT2]

Don’t Vape do a system that fits ?