GT750 setting the timing

Wayne Meuir · Post by **Wayne Meuir** » Wed Dec 23, 2009 6:29 am

POINTS SUCK!!

Wayne

tz375 · Post by **tz375** » Wed Dec 23, 2009 9:48 am

Wayne, never a truer word was spoken.

I was digging through my bookmarks the other day looking for something and bumped into www.ignitech.cz and they have some neat electronic ignitions at remarkably good prices.

So I emailed them and quick as a flash back came the answer that they sell a pick up plate, pickup and programmable electronic ignition. It can be set up as a single flat "curve" or a 2D map or 3D map if you fit a TPS.

And all for about 150 Euros.

As soon as I get some surplus cash (2011 perhaps the way the economy is going) I'll get one and test it.

Buffalo-guy · Post by **Buffalo-guy** » Wed Dec 23, 2009 10:48 am

A Boyer-Brandson ignition was installed on my former hotrod buffalo, and it hasn't missed a beat since. That was 12 years ago. The electronics are simplistic, I suppose, with two extra sparks per revolution, but it hasn't bothered it, and never goes out of adjustment. All for under $200. It's been well worth it. I also use NGK B8EV plugs with great life cycle and clean running. My stock '72 ,with Boyer, B8EV's, one size smaller main jets, and taller gearing, gets 58 mpg imperial, thats 46 US. Respectable for a 750, and amazing for a two stroke. On the highway, you can't tell it from a four stroke, with no tail smoke present. You gotta love the old Suzuki's. Check the timing marks with a dial guage, and go electronic. You'll never regret it. Cheers.
Fred

tz375 · Post by **tz375** » Wed Dec 23, 2009 3:12 pm

I have fitted triple DYNA S systems to two GT750s now. The only thing I have done with points is to put them in an envelope and send them to someone who wanted them.

We fitted DYNA S to three CB160 race bikes, a CB72 racer to name but a few.

What I had been looking for was a good system with some degree of adjustability. The ignitech has a single pickup and three lobed rotor so it sparks 3 times per revolution and not 9 times AFAIK and it is fully programmable.

It is at least two generations more advanced (pardon the pun) than Boyer or Newtronics.

Wayne Meuir · Post by **Wayne Meuir** » Wed Dec 23, 2009 5:52 pm

TZ, I have a Dyna S on my as well. Installed it in 2007, set it with a Dial Indicator, never had the cover off since.

If you try one of the programmable ones and it works out well, let us know. Sounds like an improvement from the Dyna S.

I will NEVER go back to points on my Buffalo, they are a major PITA.

Wayne

MotoMartin · Post by **MotoMartin** » Thu Dec 24, 2009 12:35 am

Points do indead suck. I remember my first car having points, seems like I was constantly fiddling with them and replacing condensors.
On closer inspection I have Mitsubishi points judging by the logo.
I adjusted the gap on the Left cylinder closer to 0.3, warmed it up, put the timing light on and adjusted the points plate, now it does align with the indicator. Now I need to take it out on the freeway and see if any of the surging remains, it ran well on lower speed roads today.
Thanks for the advice.

Wayne Meuir · Post by **Wayne Meuir** » Thu Dec 24, 2009 6:23 pm

The surging is probably caused by the carbs if you are still running the stock carbs. Their is an air jet mod that Suzuki came up with to fix it. There was a service bulletin done by Suzuki that tells how to do it.

Wayne

pjmcburney · Post by **pjmcburney** » Fri Dec 25, 2009 6:00 pm

tz375 wrote:What I had been looking for was a good system with some degree of adjustability. The ignitech has a single pickup and three lobed rotor so it sparks 3 times per revolution and not 9 times AFAIK and it is fully programmable.

That's an interesting way of making it work...

I've been playing this out in my head.
How easy would it be to create an 'adjustable' three-lobed rotor?

Instead of a single plate with the cutouts arranged around the edge 120 deg apart, how about three individual plates (one on top of the other) bolted together...

This would give you the option to set the timing for each cylinder, and would easily take into account any vagaries in the crank.

Set one plate to trigger the LH cylinder, then by sliding the plates between each other, set the other two, exactly.

Food for thought?
Cheers
Paul

tz375 · Post by **tz375** » Fri Dec 25, 2009 11:23 pm

Paul,

I had not considered the possibility of using a modern single trigger with multi lobed cam to trigger the ECU which would "know" which cylinder to send the juice to. Most modern bikes work that way but I didn't realize that Ignitech had that capability. Most of the others do not. And some just fire all three plugs three times per revolution.

As long as the metal were thin enough that would work, but setting one without the others moving might be difficult.

The reason to want that feature is presumably to allow for minor phasing differences on the crank.

I was planning on filing a small amount off the back trigger edge of any that needed to be advanced relative to the others and I was planning on doing that once per crank ie once per lifetime.

At 4 euros each trigger wheel, that's not a high risk activity.

Wayne Meuir · Post by **Wayne Meuir** » Sat Dec 26, 2009 9:28 am

When I installed the Dyna S, I made the backing plate and used a Dyna S rotor designed for a GS1100. What seemed to me to be the biggest problem was that the rotor was such a small outside diameter, it crowded up the three pick-ups to the point that adjusting them was difficult becasue they almost touched one another. If a rotor could be made that was a bit larger diameter, then the pick-ups would be spread out a little more and adjusting them would be a lot easier. If you were to do that, I don't think there would be a need to have the stacked plates since you could still adjust each pick-up individually.

Wayne

pjmcburney · Post by **pjmcburney** » Sat Dec 26, 2009 5:41 pm

tz375 wrote:Paul,

I had not considered the possibility of using a modern single trigger with multi lobed cam to trigger the ECU which would "know" which cylinder to send the juice to. Most modern bikes work that way but I didn't realize that Ignitech had that capability. Most of the others do not. And some just fire all three plugs three times per revolution.

So, the Ignitech has circuitry which 'knows' or works out which trigger pulse is to fire what coil?
Do you set it when you first install the unit?

As long as the metal were thin enough that would work, but setting one without the others moving might be difficult.

True. But, it couldn't be any more fiddly than setting points, what with the fact that the points gap itself has a subtle effect on timing as well.
I imagined the individual plates might be indexed in some way via a serrated inner ring...?

The reason to want that feature is presumably to allow for minor phasing differences on the crank.

I was planning on filing a small amount off the back trigger edge of any that needed to be advanced relative to the others and I was planning on doing that once per crank ie once per lifetime.

At 4 euros each trigger wheel, that's not a high risk activity.

Of course

, I'm a silly bunt... (Monty Python reference

)
That would be much easier, and as you say, even if you wreck or otherwise 'set' a particular trigger wheel, it ain't too expensive to buy another one.

I am most intrigued by this particular unit. Anyone planning to buy one?

Cheers
Paul