any honda motorcycle techs on here?

[headwrench]

i have a 1986 honda shadow vt500. i have spark on one cylinder only. i ran an ohm test on the mag pick-ups & they show ok. same with the coils & wires, they check out ok. now im down to the cdi box. is there a test to check this box? is there any way to change to another ignition system? this cdi box is very expensive. any help? thank you

 

[superfish]

I had an 83 shadow at one time. Long time ago so be careful with what I tell you. As I remember:

Shadow has 2 CDI boxes. They may not be mounted near each other. One runs the tachometer as well as providing spark. Find them and swap them. Your symptoms should follow the box. Then you know which is bad.

Some times you can find a box on eBay. Also, check this forum (http://www.v4hondabbs.com/). It's for the V4 Hondas but there are directions for repairing CDI boxes.

Good Luck,
bp

 

[headwrench]

thanks this has one cdi box but with 2 wire sets from it. one with white plug & one with black plug. i have checked e-bay daily & a box for my bike has never been on there yet, but i will keep on checking.

 

[wnstwolf]

I worked for a Honda Dealership in RI for about 10 years supporting my MX addiction. Hate to say, while you can try, the CDI boxes are not something that were meant to be repaired. Great when the work but prone to be the weak link in the ing. system. Bad thing is most shops will not let you return them if you order one and for a bike that old just locating one is a chore. any Salvage yards close by? while part numbers may not match the CDI's for similar displacement bikes were all pretty much the same. As mentioned Honda palyed around with 2 and sometime 4 boxes ber bike. You should check the aftermarket as well maybe one to be had from one of the usuals..

 

[mzbk2l]

I have an '81 CB650 that uses two modules and employs a "wasted spark" system. I haven't tried this yet, but I've been fascinated by the conversion to GM HEI modules in place of the Honda CDI modules; supposedly the results are great.

http://www.hondacb650.com/viewtopic.php?f=4&t=3142

Might be an option if you can't find reasonable prices or availability on stock parts.

 

[wnstwolf]

MZ is on to something. I am sure there is a system of HEI or other car applications that would work and be a whole lot cheaper then trying to locate a 30 year old Honda part. Possibly a Hond Car ignition part? I say this because all honda motorcycle parts were shipped in packages with red writing on them and honda car parts with blue. As the bikes got bigger and bigger I started to notice some parts were in blue backages, my take was it was a part that was for both car and bike? or maybe just a wrong package that only I noticed!?

 

[ny1]

It's hard to test them and get a conclusive answer with a ohm meter, but there should be some specs out there.

 

[Seb650R]

Get yourself a shop manual. If there is a way to test the CDI box without specialty equipment it will tell you the procedure in the service manual. As others have mentioned, go to a boneyard and you can probably find one that will work with it.

 

[Canadian Cowboy]

i have a 1986 honda shadow vt500. i have spark on one cylinder only. i ran an ohm test on the mag pick-ups & they show ok. same with the coils & wires, they check out ok. now im down to the cdi box. is there a test to check this box? is there any way to change to another ignition system? this cdi box is very expensive. any help? thank you

It does sound like the CDI has crapped out or I should say one side of the circuit board has.
Can you open the box and take some close clear pictures of the complete circuit boards and post them,I have to be able to read the numbers of off the Op amp chips,some are covered in epoxy or a glue and cant be fixed easily.
A voltage spike and/or a intermittent bad ground usually takes them out.
Also check the side stand switch follow the wires up to the relay and from there to the CDI some had to inputs entering the CDI box from the relay to kill the spark some didn't off hand I cant remember if your model has 2 inputs but it is worth a look make sure you have continuity and not a open circuit.

CC