Rotax 185 CDI Conversion...easy!

[lazair3ca]

[rayjb60]

[lazair3ca]

[rayjb60]

[lazair3ca]

[rayjb60]

[rayjb60]

I took a close look at the two flywheels and the picture comparing the two, and you are right, they are different.

I measured the location of the reference hole and compared it to the original and it is about ~25 degrees ahead of the other hole.

This means that I will either have to advance the armature plate by that much or use the new flywheel.

Since at this point it looks like it will be easier to use the new flywheel, instead of drilling new holes in the armature plate, then I will use the flywheel.

Im looking forward to less kick on the startup.

Thanks for figuring this out.....I have no idea how my engine even ran so well, being 25 degrees out of tune, but perhaps the ignition is capable of adjusting itself.

I'll post an update after I have run the engines again with the change.

Ray

[lazair3ca]

Ray,

You figured it out. I have been goofing off skiing, CASARA training, building extensions for the CSM toboggans. Tomorrow we try again to get the engines running. George has converted both of his engines so we can try them out. The last time it was -18 deg C. Tomorrow should be 5 deg warmer. We will use fresh fuel and preset the needle valves to the recommended setting.

The three bolts do hold the flywheel to the center section which is keyed. Our center sctions have two keyways in them. Be sure you use the right one. The three bolt pattern is not symetrical. One distances is further apart than the spread on the other two! So you can only put it together one way.

I do not know how your engine could run with the timing so far advanced.

I have posted some more pictures on the modified controls thread.

Cheers,

[rayjb60]

Last night I took the old flywheels off and put the new ones one....it was a lot simpler than I expected.

The hub is actually part of the plate with the 3 bolts in it and comes apart as one unit.

I did not have to do anything special to remove the hub and replace it on the new flywheels.....just the 3 nuts are remove and it comes apart easy, with a couple taps.

I dont know why they did not just make a new armature plate with different holes in it and keep the existing flywheel....it would have been a cheaper upgrade that way.

Seems like the coil is advanced 25 degrees more than the existing points timing, so that everything fires at the right time.

I will run the engines this weekend and report what I find out.....Im hoping the starting kick will go away.

[lazairiii]

Ray and Bill,

If either one of you have any way of checking the max RPM you are achieving with the newly installed CDI units, that will be a vital way of determining if the new CDI conversion is turning up to the range the points were turning. Remember the point were in the 5800-5900 range (variables here I know), but see if you can determine this if possible. Who knows, maybe it will me slightly better, that would be nice huh!

Thank you,
George Curtis
Utah