Ignition

What system should I use on my rephased motor

Newtronic Ignition Install Guide
By C Bath Dec 2007 

This paper describes the installation and issues I had when installing a Newtronic (Yam6) pointless ignition kit into my XS-650 1978 special. I took a few photos’ that will demonstrate some of the points I will discuss. Hopefully this will be of some use to our members in the XS-650 club thinking of fitting such a system. 

Firstly I would recommend fitting a pointless ignition system to your bike, once they are fitted the bike will start and run much smoother than with the older points and condenser system. Secondly you never have to worry about setting the timing again, also with less moving parts this has to be a better system. 

  1. The instructions in the Yam6 kit says to remove your points including base plate and disconnect the old wiring Grey and Orange, wires to both coils. Also remove both condenser wires. Remove the cam (from the shaft) which opens and closes the points.
  2. Next fit the supplied base plate with sensors into the timing cavity where the points were. I found that the supplied base plate did not in fact fit. I had to reshape it to fit into the cavity. This meant before doing so I had to remove both sensors from the plate.
  3. Now the instructions says to fit the supplied pointless rotor to the cam shaft position where the point cam was. Being careful not to disturb the mechanical advance mechanism. Again I found that the supplied pointless rotor did not fit the shaft. I had to pull it apart and make the hole larger so it fitted over the cam shaft snugly.
  4. Next I assembled the entire point less ignition as per photo 1. I guess if the parts fitted first time the process would have taken around 40 minutes, instead of half a day.
  5. Fitting the electronic unit. The instructions say to fit it to the near side left hand side cover. I found this to be a very tight fit. So I decided to fit the unit under the seat towards the rear of the bike. See photos.
  6. The instructions show a wiring diagram of how the new point less sensors wire back to the electronic unit and how the unit wires back into both coils. Again I found faults. The wiring diagram is incorrect and I had to swap over the coil wiring, to make the bike run. I also had to play around with the connectors to get them to fit.

Conclusion 

Although fitting this unit was a bit of a task, it proved to be worth while doing. If anyone needs more information please e-mail me.  

 

 

  

Reshaped Base Plate and Rotor

 Wiring changed to make the bike run from supplied wiring diagram which was wrong.

 

 

Modified connector

Photos 3&4 Electronic unit mounting under the rear position of the seat.

Electronik Sachse in Germany now make an ignition system for the standard XS650 but I emailed them and they are willing to make one for the 90° rephased motor. Click on the picture to check out their website. The price is estimated to be around AU$500.

New Ignition System From Mark Whitebook

Stock 360° Motor

I have been talking recently, via email, to Mark Whitebook in the U.S. about adapting an ignition system he produces for the Honda CB series and it turns out he started the design of this system with the XS650 in mind. Mark sent some pics of the systems he currently produces for the Hondas and says it will adapt to the XS with little more than a change of pickup plate and rotor.

This pic shows just the control modules on a pretty blue background, and with a 6" stainless rule for scale.  At far right is the dual-fire module (quite small), centre is the BT-05 module, and at far left is the module from the CBX-06 system (aptly, for the Honda CBX).  This module is a little bigger than the BT-05, and has the connectors for power and sensors positioned at opposite ends, instead of side-by-side.

Dual Fire Ignition System

This pic shows the dual-fire rotor and sensor in place (you can see both at once; the rotor is in front of the sensor PC board).  The PC board in this one is a prototype, and so is brown, not green, and doesn't have the silk screened graphics.  Production parts look nicer.

This system, currently being developed for the XS650, is best described as working identically to the standard electronic ignition systems fitted to the US models after 1980 in that it fires both cylinders each rotation of the crank using a dual output coil. Typical wasted spark ignition like the Boyer Bransden system.

Rephased Motor

BT-05

These pics show the single-fire pickup assembly, the first pic with the sensor housing in place and the second with it removed (the housing covers the rotor).  A system for  rephased XS650 would be based on this design - same rotor, same housing, new PC board (the green thing).

The first XS650-90 ignition system ready for shipping.

You'll note that the CBX module has two blue potentiometers on its face, while the other two modules each have just one.  One potentiometer is for idle-advance adjustment (which all three modules have); this makes full-advance and idle-speed advance settings independent from one another, so that you can advance or retard the all-in timing (by rotating the sensor plate, in the time-honored way) without having to "live with" a default idle timing setting; you can twiddle that on its own. 
 
The second pot on the CBX-06 module lets you select the advance rate; all-in timing adjustable anywhere between 3,000 RPM and 4.000 RPM.  I am considering using the CBX modlue as the basis for a rephased XS650 design, in place of the fixed-advance BT-05 module, so I thought I'd throw in a pic.  In my experience, the size difference is not so great as to be prohibitive, and the pricing I've arrived at could be met with either module.

There are now two models available for the rephased motor, XS650-90 for the 270° and XS650-83 for the 277°. If you are interested in buying one of these units then give Dave Rayner a call, he is the sole Australian agent. Dave's email address is dave650@bigpond.net.au 

Installation instructions

Dave Rayner's radical belt driven OHC posed a problem because he wanted to use the Boyer system as he could not keep the mechanical advance/retard mechanism, nor could he put one on each end of the cam for the rephased motor as an alternative. So he came up with the stacked Boyer ignition system pictured below. An expensive but workable solution and quite ingenious don't you think? Looks similar to the ARD magneto that was once available for the XS650 and nicely balances the belt driven OHC on the other side.

December 30, 2007