Swapping connections on the 77 cdi

[SpitfireKing]

Gents,

I'm working on my 77...or 78 Liquifire and I still have no idea which because there vin plate looks to have never been there and I cannot find any markings under the seat or near the gas tank whatsoever....anyway

I got this machine and it has the round connections on the mag and cdi, and it had no spark when I got it, so I went for the easy fix and replaced both coils and robbed a new cdi from another motor I had laying around. my only question is does anythig change in the wiring when you go from the block style (parts motor) to the round style connector on my good sled? I just went colour to colour when I swapped the ends, but wanted to be sure that was right?

I read through a lot of the good testing procedures etc, and will do that later, but just wanted to make sure I'm not doing it in vain if I have 1 or 2 wires in the wrong spots with the swap.
Thanks guys

[harleysportster]

The 78 Liquifre has a hood vent for the front mounted radiator. If yours has that, than it is a 78. The 78 Liquifire also has a single type seat.
The color codes are the same between the rectangle "B" type and the round type connectors.
Did you ohm out the stator as outlined in the FAQ section. This should be the first step before swapping out parts. The low speed windings in the stator is a common failure.

[SpitfireKing]

The coil wires were completely shot, so the coils had to be changed anyway, seeing as they had a brain fart with those one's and you can't change leads...

The cdi wires were a bit crusty, so that was my #1 thought...but again I would have changed no matter what...but wanted to be sure I wasn't doing it wrong, as I can see a very faint spark there when I pull...but nowhere near what it needs to even fire.

[SpitfireKing]

just an FYI if anyone is reading this topic...make sure you read the Prestolite cdi topic in FAQ's.....I missed the topic on switching the red and white wire until tonight and when you go from the old round to block connector you need to know that.

Thanks for the info on the site...a guy could have spent months figuing that one out

[JD_Sledder68]

I just got done changing out the CDI on a 77 Liquifire tonight. Purchased the SPI CDI unit with the rectangular block connector, then realized that the sled has the round leads on it. I cut the leads and soldered the round connectors onto the new unit, swapped the coil wires (red and white) and it fired right up and ran like it should.

Not sure I would have accomplished this so easily had it not been for remembering this thread about the red and white coil leads. I almost completely forgot about it as we were getting ready to fire it up.

[harleysportster]

Maybe the CDI boxes from SPI are the onlyu ones that need the primary wires switched. I had used a box from Snow Stuff years ago without any problems.

[400brian]

I ran into the reversed coil leads on a rebuilt CDI from Image.

[lwb140]

its pretty simple to tell if they are wrong a simple comprssion test with a spark tester attatched watching the spark flash as the compression builds . you can also simply swap spark plug wires and try to start wade

[JD_Sledder68]

I used jumper leads (alligator clips) to test before bolting any wires down on the coils.