New Member with Rusty GTR to Restore in Australia.

[czmike]

Hi Folks,

I'm an older guy (feel about 26 though) who joined a while ago but I've been busy (with a Honda CB900F). Living in Melbourne, Australia I rarely see Bridgestones but I've always thought they were just the way a motorcycle should look and now I own one. Earlier this year I bought a very rusty "Parts Bike" off ebay and shipped it here. Restoration has not commenced yet as I am gathering the parts & info I need to do a thorough job. My aim is to do a "beautiful" job which will be a new experience. My other bikes (JAWA's, CZ's & Honda's) work fine but are not beautiful or even restored as such. Function has always been of more interest to me than form. With the GTR there are so many NOS & re-pro parts available I feel duty bound to do nothing less than an excellent res-to. I have two stroke experience, having been a kart racer, and I am an electronic engineer so the points ignition will have to go from the GTR eventually. My interest in Czech bikes led me to a Czech ignition system (IMF) that has variable ignition timing so I want to put one on the GTR which should improve things.

I look forward to interacting with you folks in this, hopefully better, environment to do it in.


Best Regards,

Mike Munday,
Seaford,
Australia

[CafeTBird]

Welcome, Mike!

Funny to hear someone say that a Bridgestone is an "easy" resto... but considering the other bikes you have, you are probably right!

[jhlangtry]

Mike,

I own a fully restored 1967 GTR, which I bought second hand in 1970.  I have played around with building an electronic ignition with a view to using it on a racing 125, that I was going to build from a 175 DT - a project long since abandoned.  I was using the triggers from a Kawasaki A1, since it had a similar alternator setup to the 175DT and the GTR, but had a lot of reliability problems with CDI circuit that I built.  I'd be interested to know what approach you are taking to electronic ignition for your GTR, since I still have the trigger set-up and the glimmer of an idea for a racing GTR when I retire in a few years time.

Regards

John Langtry
Canberra

[CafeTBird]

Hmm... looks like the CZ has a little more room to play with for that IMF ignition?  I have often wondered what one could do with a Boyer set up....

[czmike]

Hi Scot,


I didn't mean the resto would be easy, not at all. It definitely won't be as the bike has a frozen engine and is very weathered. Its just that sourcing parts for it has been pretty easy so far which surprised me. This has encouraged me to do a good looking resto.

Actually spares for the CZ's & JAWA's are also easy to procure I find. Maybe I'm just lucky?
I do put considerable effort into the search though, both on-line and at swap meets, etc.

The ignition I am thinking of using does fit inside the GTR's alternator in place of the contact breaker plate.
I need to engineer a mounting plate for it but it looks encouraging so far.
Maybe John from Canberra would like to road test a system like this if I fashion one?
I won't need one myself for quite a while yet.
I will reply to John and maybe then we should create an electronic ignition thread, if there is no existing solution for the 350's?


Best Regards,

Mike

[czmike]

Hi John,


Sorry for the slow response but it’s a busy time of year isn’t it.
It’s nice to hear from a local GTR owner.
That must be nice to have had such a long acquaintance with a GTR from near new.

Is there no existing electronic ignition upgrade available specifically for the GTR?

If not I have an idea for adapting an existing, innovative product that I have some experience with which gives excellent results. It is not a CDI but if you are not racing then I think CDI is not necessary. The unit I have in mind acts as a transistorized-switch replacement for the points & condensers and would use the original coils (but it does much more than that!). If the original coils are good performers using points then the results will be excellent once this unit is fitted. Its trigger method is optical (infrared) and uses a chopper disc that you mount in place of the point’s cam. The output of this small printed circuit board drives the original coils through the original wiring. This means there is no "black box" and nothing additional outside the alternator to give a clue that there is modern technology inside. Yet, there is a heap of excellent features on board. The small, round printed circuit board carries all the ignition control components and will fit inside the GTR’s alternator where the points were mounted. It was designed for exactly the same application in JAWA 350 two stroke twins.  The JAWA alternator is driven off the end of the crankshaft with an aluminium cover fitted over it that totally stops air flow. This module is therefore designed to withstand heat and it is lacquered to seal it from moisture. The high current switching transistors, which run hot, are mounted underneath the module so they contact the metal part of the alternator (or an adaptor plate in our case) when you screw it in place. This acts as a heat sink for them. There is a 9 pin serial communications connector (IBM type RS232) that faces outwards so you can remove the rear alternator cover and plug in your laptop or PC. You can then set all the parameters for the unit and even run the bike while watching the ignition timing change live on analog type gauges on the computer screen. The module has a microprocessor on board that provides all this functionality and variable ignition timing which is something that has not been implemented often enough in two stroke bikes I think. It also provides variable coil excitation (charge up time) which enables the coils to maintain high voltage output at high RPM but not burn out the coils at low RPM. Two different ignition timing curves can be established and then switched between while riding and there is an adjustable rev limiter also. For the GTR application I need to engineer mounting adaptors for the board and the chopper disc so I am looking at that now. I also plan to test the original type of coils, I have some NOS of those, to see if they are good enough. I am keen to build this rig up even though I won’t have a bike to use it on for a while. If I can’t find somebody closer to be test rider maybe you would like to give it a try John?


Best Regards,

Mike

[RayK]

Hi John

I am restoring a 1967 DT 175 and am not far from Canberra, so if you wish to compare notes please contact me on mobile 0437 401 600.

Ray

[OldSwartout]

I used a Dyna S system to build an electronic ignition for my 175.  The 350 would be even easier.  The Dyna S systems are available for about $75 used on E-Bay, new ones are around $150.  Get one for a Kawasaki Z1 or Suzuki 1000 (probably nearly any will work as you'll have to modify/make a mounting plate and do a little machine work on the trigger rotor/points cam.  Overall, it's easier than coming up with something new.