Rotax 185 CDI Conversion...easy!

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Postby Bill R » Fri Jan 28, 2005 8:27 am

I can not up load pictures anymore.
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Postby jb88ci » Fri Jan 28, 2005 9:14 am

My old Harley shovelhead uses a lord mount similar to the ones on our lazair engine mounts for monting the battery box and oil tank to the frame. They may work for this application.

I've been doing some cdi research. Vespa scooters use a 6v cdi box. I'm guessing the new stator coil in the wildfire kit is a 12v winding for the new cdi box.

I bet if the timing issue could be resolved, one could use the lighting coil to power the cdi box or a universal 6v lighting coil could be used. The ones i've found on the 'net have similar shape.
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Postby Guest » Fri Jan 28, 2005 11:25 am

Looks like the CDI kit comes with an original type sparkplug cap. Not good. Read Wildfire Tech notes.

Compression releases need to be replaced when they get worn and loose. They need to be removed if they have not been modified to keep the head from becoming disconnected from the stem. When the head of the release comes off the stem will get injested directly into the cylinder. Some oil leakage from the releases is entirely normal.

Is anyone planning to time the engines in accordance with the Wildfire CDI install instructions ???

Possible replacement Lord part #4624-479. (may be a slightly shorter mount)
XTO Inc. in Liverpool, NY. (315) 451-7807.
http://www.westernrubber.com/
http://www.lord.com/DesktopDefault.aspx ... EGORY_ID=7
http://literature.lord.com/root/other/flexbolt.pdf
Also Rpm Mechanical. Burlington, Ontario, Canada tel # 1-888-842-5668.
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Postby jb88ci » Fri Jan 28, 2005 2:36 pm

there's already a tech note or lettair on the compression release...you just need to silver solder the sucker together at the crimp..
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Postby Guest » Sat Jan 29, 2005 9:09 pm

Bill R @ Jan 28 2005, 08:27 AM wrote: I can not up load pictures anymore.


If you can't upload pictures it probably means you were not signed in at the time you tried to upload the pictures. Try it again signed-in or logged on under your user name and password. You should see a the "Browse box" that lets you upload directly from your picture file.
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Postby Guest » Sat Jan 29, 2005 10:43 pm

Could you post links to any coils found that would be possible candidates.


Quote: "I'd bet if the timing issue could be resolved, one could use the lighting coil to power the cdi box or a universal 6v lighting coil could be used. The ones i've found on the 'net have similar shape."
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Postby rayjb60 » Mon Jan 31, 2005 12:02 am

Update on the CDI conversion...Ray

I went back and used the supplied flywheel with the 25 deg advance and sure enough the hard starting kick totally disappeared.

I ran the engines this week end although I did not have my Tiny Tach yet, but found the Rotax seemed to have more RPMs that the original points configuration.

My Left engine was a little slower by perhaps 100 rpm, so I will advance the plate a bit to see if I can even them up.

They sound awesome and were pulling like crazy on the ground.

Im a 225lb guy and with my heels dug into the sand hard, I could barely hold the Lazair in place for the full power run up.

I created a movie of the test and will upload it on monday evening to the Lazair.com/forum as a link.

The engines started so easy on 1 pull.....even after sitting for a while....starting will never be an issue again....it was certainly worth all the trouble.

I hope everyone else has similar success.

I measured the resistance of the supplied Wildfire armature coil....its 242 Ohms.
I'll have to get the windings wire diameter as well so we can figure out how to wind our own.


The existing lighting coil is 0.5 Ohms.
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Postby Guest » Mon Jan 31, 2005 2:13 am

Great report Ray. This is good news...or bad I suppose. I was personally hoping that we could get away with our existing flywheels and save that cost, but after all of this it is apparent that we need all the pieces supplied by Wildfire for the timing to be correct.

Now, I'm waiting for you to get that tiny tach and report on the max RPM!!! I"m very curious.

By the way, are you using the Bi-Props or the Prince P-Tip props on the engines???

George Curtis
Utah
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Postby rayjb60 » Mon Jan 31, 2005 2:40 pm

George,

No...you do NOT have to use the supplied flywheel....just advance the armature plate by ~25 Degrees and drill new holes.
(Before drilling let me measure the angle with the utmost accuracy to give an EXACT figure)

Still waiting on my Tach to arrive....it should prove interesting.

Im using the Bi-Props.
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Postby rayjb60 » Thu Feb 03, 2005 4:00 am

Here is a movie of my CDI conversions running: Rotax 185's with CDI Ignition
(Right click and save, if it does not open here)


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.
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