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PostPosted: Thu Feb 03, 2005 3:58 am
by rayjb60
Here is a movie of my CDI conversions running: Rotax 185's with CDI Ignition

There is some strange pops near the end....its some kind of wind noise, definately not the Engines.....they run real nice and strong.

I also got my Tiny Tach in the mail today, so this weekend I'll be getting some rpm numbers to post.

I still have to advance the one engine a bit to even it up with the other one.

PostPosted: Thu Feb 03, 2005 8:44 pm
by Guest
Unless you have verified rpms with a Tack you really don't know if the engines are hitting Max. You may think the motors are doing real good "sound and feel wise" when they are actually running a good bit under best rpms. 100-200 rpms under best revs per engine is a bunch of lost thrust in total for a Lazair.

PostPosted: Fri Oct 14, 2005 6:16 pm
by rayjb60
Here is what I measured on my Tiny tach:

RPM's for CDI converted Rotax 185 engines.

Left Engine 5770 rpm
Right Engine 5860 rpm

These engines have about 8 hrs total on them all within the last year, so they are virtually new.

I also put K&N filters on them and there is no impact on RPM.

I have another movie of the Engines showing engine responsiveness as I hammer the throttles from idle to full power back and forth repeatedly so you can see how they follow without any hessitation or skipping a beat......excellent response and reliability.

I'll see if I can post it this weekend to so admin can load it for me here.


PostPosted: Tue Oct 25, 2005 8:23 am
by lazair3ca

Great input on your CDI conversion.

George installed his tinytack yesterday and did some preliminary testing. Unfortunately he ordered the wrong tack so he is getting twice the reading he should. But be that as it may his initial readings show an idle of 2000 RPM and a max rpm of 5400. They should be lower and higher which means we have some tuning and timing to do yet. These are old tired engines.
I was reading 5600 and 5700 on my magneto engines a year ago. I look forward to installing the CDI on mine in the near future but why change a good thing? Because they start a lot easier?

Note to other potienital CDI converts. The CDI has two pulses per revolution.

PostPosted: Sat Oct 29, 2005 1:53 pm
by artman12us
Do the points have one or to pulses. Thanks Art

PostPosted: Fri Nov 04, 2005 2:27 am
by tommyb
points have one-
did any of you guys use a digital tach to verify the new tiny tachs?

PostPosted: Fri Nov 04, 2005 2:28 am
by tommyb
anybody know at what RPM rotax actually hit 9.5 hp?

PostPosted: Tue Dec 27, 2005 2:46 pm
by rayjb60
Verify with digital??? The Tiny Tachs are digital.

The pickup wire is wrapped around the spark plug cable and counts the pulses to the spark plug.

I had to set my Tiny Tach to 2 pulses per revolution for it to read correctly.

Points are 1 pulse per Rev since it is lobe triggered off the crank shaft at one point only.

The extra spark does no harm except perhaps wearing out the plugs a bit quicker.

PostPosted: Sat Jun 09, 2007 4:28 pm
by art
I have tiny tach 2c One pulse per revolution. This was confirmed by Wildfire. I am getting about 5800 on each engine. I have CDI. Art
Model Description Price
TT226NR-2C Standard Model
Used on engines with one spark firing on each revolution of the crankshaft.
1 cylinder 2 stroke (reads 1x / revolution) Briggs, Kohler and Honda type engines.
4 stroke with electronic ignition and no points.
2C can also be used on 2 cylinder engines where the cylinders fire 1X per revolution.
Note 1: Engines frequently referred to as a "4 stroke" may not be a true 4-stroke because they fire on the exhaust stroke as well – requiring a 2C.
Note 2: You cannot reset, hours will accumulate.