97 Ignition on a 95

[Pep]

So nothing like a last minute emergency before the race - stator blew up, all out of condensers, but I have a spare 97 ignition.
Has anyone mounted the stock PVL from a 97 on a 95? Wondering where I should set the timing.
I have a modern PVL on a 95 set at 1.9mm BTDC - runs great, but that’s far from the 3.95mm BTDC called for on a 97.
Any advice would be appreciated
Laurie

[michael_perrett]

I have mounted a 97 CDI ignition system on a 94 Wombat, No problem, except different mounting tabs on the backbone.
Mike Perrett

[bobwombat]

Pep: I mounted a Model 97 e-ignition on my Model 95 & it's timed at 2.9mm BTDC. This was after much homework discussion & phone calls around the trusted Hodaka clan. I think part of the problem is there are different recommended timing settings. 3.95mm BTDC is stock but others have used 2.9mm for modified applications. Very trusted buddy, George Cone, tells me he merely sets the stator dead-center in the mounting slot & told me that'll get you real close & he's never had ignition problems! So, go figure.

The point is, you CAN use the Model 97/98 e-ignitions on the 94 & 95 bikes.

Bob in AZ

[eichco1]

This is how I mounted mine on a 99 frame.



Mark in Illinois
#492

[eichco1]

Like Bob mentioned, I set all my Hodaka 100/125 CDI's at 2.9mm.

Mark in Illinois
#492

[Pep]

Sweet! Thanks a million guys!
I stripped the bike to mount the PVL, but started feeling bad about drilling on someone else's very original CW. So I took apart a pit bike and used the 94 points ignition on the 95. Race-ready and unmolested.
But it brings up another question: I have a modern (Penton Products) PVL on my 95 - timed at 1.9mm and just awesome for the last year of racing and trail use. Another friend has a PVL (MZB/PowerDynamo type) on his 95 - also timed at 1.9 - past owner of that bike had notes recording the testing and backing off the timing from 2.4 eventually down to 1.9 before being satisfied.
I know there must be a gray area in those numbers where a bike will still run fine, but what gives? Are 2.9 and 1.9 just not really that far apart?
I'm guessing the suggested 3.95 on a 97 is a product of the porting differences, since the stroke is the same?
Anyway, just curious about the range in timing specs, thanks again everybody for the quick help.
Laurie

[Bullfrog]

Laurie:

You seem to be using "PVL" as a generic identifier for electronic ignition systems, which would more properly be identified as "CDI" (Capacitor Discharge Ignition). This could be important because each manufacturer of "CDI" systems has its own design parameters. Among those are the amount of ignition "advance" (actually "retard") the system has built in.

The internal rotor CDI which was stock on the Model 97 and 98 was "state of the art" when produced and offered a WHOLE BUNCH of "retard" as engine RPM increased . . . something on the order of 12 to 18 degrees (information sources vary on how much change there is between idle and 10,000 RPM). With that much timing change, it is "safe" to set static (idle) timing wayeeeee advanced so that the engine will provide significant "punch" at low RPM . . . but not be so advanced on timing that it cooks itself at high RPM on uphill straight pull.

The modern PVL and MZB . . . "CDI" systems don't provide for nearly as much advance/retard over the full RPM range (the current "state of the art"). Therefore, static ignition timing must be set at a more modest starting point. Final selection of the "proper" static timing point depends upon the advance/retard curve, porting, pipe, carb, compression, fuel, spark plug/head combo.

As a really rough (but still quite informative) "rule of thumb", you'll find most Hodies and most vintage two-strokes to be happiest when the ignition timing curve contains 25 degrees BTDC somewhere in the curve.

Ed

[Pep]

Excellent. Thanks Ed, that was just the information I was wondering about - education much appreciated!
Laurie