[Feanor_twh]

How did you adjust the CDI from the Suzuki 1150 to work on the GS750ES?

I always lubed the cam, but thought the fit might not be quite exact. I have ordered a strobe lamp to make sure of the adjustment and correct operation of the advance.

You're slowly convincing me that points are almost as effective as CDI, so your effort isn't being wasted ;-)

 

[Kawasakian]

I miswrote that, The CDI from the 1150 fits, will get your bike started, but it will run like crap. I was just about to go back and edit that. Sorry!

 

[Feanor_twh]

I can't find the power curve of the Yam650, but...

-Yamaha XS650: Max Power: 53hp @ 7200rpm. Max Torque: 54Nm @ 6800rpm
-Kawasaki KZ400: Max Power: 36hp @ 8500rpm. Max Torque: 32.3Nm @ 7500rpm

Do you think that the Boyer Bransden CDI (that I have) designed for the Yam650 could be adapted to the KZ400 by advancing the ignition timing a little?

It is not because I have insisted on mounting it whatever happens, it is an attempt to adapt it because otherwise I will have to sell it.

 

[Feanor_twh]

Today I have done tests with the strobe lamp and I have seen that it has a fixed idle advance, and then at 3000rpm it advances a few degrees and from here it stays fixed at the following useful rpm's (which go up to more than 8000).

That makes me think that even a CDI for Yamaha XS650 (which does not match in terms of power curve) may perform better than the centrifugal advance that remains fixed from 3000rpm.

What do you think about this?

 

[Kawasakian]

The CDI from the Yamaha does not have the RPM cap that the KZ400 needs. If you advance the ignition timing, it will (may?) cause the problems that advanced timing causes, like really hard starting because it is igniting the plugs too soon. On the other hand, if you could live with the rpm limit ( are you really planning on redlining the 400?), I would think not. I would set the idle timing where it should be, as that starting point will get the bike running, the, running the Yamaha CDI would advance, if you start hearing detonation, don't rev the bike that high. The trick would be to look at the timing curve with a timing light an extrapolate if it would work for you. The Kawasaki revs higher. You just may not be able to rev up to the redline, but the bike could be quite ride-able. I would give it a shot, if I was in the same situation. All connected properly, no damage should occur to the CDI, though I would not advise revving the crap out of it, so you don't blow a valve or something. My gut says you just won't teach the redline. Get it together and see how it rides. Retaded timing tends to make engines run hot, advanced timing bends valves, usually intale, or it blows the compression out of the carb.

 

[Feanor_twh]

I finally returned it. I am now waiting for a specific kit from 7thgeardesigns (7th Gear Designs - Ignition Kits). Although it is expensive, it looks very good. The points/mechanical advance system seems too imprecise to me and I don't mind investing in upgrades for a bike I'm going to spend a lot of time with.

I'll post the results, in case anyone might be interested.