Cdi Unit Restoration For A 87' Vfr 700 F2

Hi,

Has anyone restored one of this cdi's ?

Looking at the capacitors of my cdi,there is only three burned at the bottom of the main board !

 

Check this out.

If you know how to manipulate a solder gun, you CAN fix a CDI.

First, ensure you are using leaded solder. not the lead free stuff. Back in the day, they didnt use the lead free. Lead free solder requires about another 80°F temperature to liquify. Today, manufacturers use a different epoxy polymer for their base circuit board material, which can withstand the higher temp... boards from 87 dont.

Start with the capacitors. Keep your board facing down, with the blown capacitor down. Use a pin tip. keep it clean too, wet it often. Gently pull the capacitor as you resoften the solder. Do this for each, and you can easily pull them out. Replace them in a reverse order... again, load from the bottom.

If your unit continues to not work properly, start at the fuse break, and work your way out from main power. Check all ground connections and ensure they are properly fitted.

Similarly to the visual indication of the capacitor, your resistors will have a cracked or brownish look to them. Radio shack will have replacements. Ensure you replace same rating capacitors and resistors... I know this probably didnt need saying, but... meh.

there is a power diode on board too, be sure you Ohm this, and ensure it is also not faulty.

My guess would be that if you blew caps, you probably have a closed short somewhere. course ... unless its in an open area, where you can get a 1/16inch drill bit in there to re-break the connection and subsequently re-epoxy it, this is a non-recoverable failure.

I would recommend keeping a 12V battery close by, and occasionally connect it after each part replacement, and check for a general power to ground cross check to your electrical print. if you get a full pass, then move to Ohming each set of resistors. If you are fortunate enough to successfully repair the CDI, I recommend not running over 7,000 RPMS until you determine what cause the caps to blow in the first place.

Similarly, if you are able to ride the bike, please keep close to home for a while until you are confident your work will hold.


(All that said, I would prefer to simply buy one from eBay)

Good luck, Let us know how you do?

 

pictures

If you repair it and get it working again post pictures....keep me posted regardless please. I have not had one of these fail for a very long time and when I needed one last they really did grow on trees.I know that is not the case now so please let me know how it turns out.:thumbsup:

 

I'll do !

Very helpful comments Ghost,I have located one of those in about 180 $ but that's in case my fix didn't work out !

 

you bet !

regards..

 

Cdi Unit Restoration

Guys,the fix works and I have spark again,so the costs were:

60 cents for the capacitors.

8 pack of beer for a friend (electronic tech.)

toe cutter,here the pics ,the ones switched are those in the bottom of the main board!

Ghost[/B],thanks for the comments !

regards..

 

this is the little black box under the seat right?

 

Yep !

I was dealing w/o no spark but know Ihave !

 

were those from raido shack............ what the resistance on those. I see gold , orange, purple is the top one brown??????

 

Cdi Restoration

Don't know !

I've just get the pack of beers!

 

In order from left to right, they are;

12mOhms +/-5%

68KOhms +/-5%

.96 ohms +/-10%

I really like this site.

Identify your Resistors


The thing to keep in mind for resistors is… they don’t have to be put in a certain direction. So, for example the second one CMR put in is backwards if you go look it up.

When replacing resistors, if you have ANY doubt of the resistance, (cause it makes a huge difference), just take the unit with the bad resistors to radio shack, and point to the ones you want replaced. Some locations will do the work for you for a small fee, like $15.00. As CMR has demonstrated, a few $0.60 resistors can save you $180.00 so, paying the $15.00 fee is a no brainer, (so long as you know that’s your problem).

Good job CMR. You are most welcome. The beer is a nice touch. Truthfully, a little alcohol will steady your hands when soldering… a little. Lol.

 

Thanks for the link !

regards..

 

where is this located exactly i found a small box in the rear but didnt have any of the same parts you have described in it

 

Way to drudge up an old thread amigo. Just kidding, the CDI box is the little black plastic rectangular unit under the rear of the seat.

 

Not to thread jack but since its on the same lines .. I am not getting power to the fuel pump but I can hook 12 v up and it works like a charm that is the only thing why I cannot ride .. I hate staring at my bike and cant fix it... oh btw my tach doesnt work when I get it runnin from priming fuel pump

 

Well, you say your pump gets no power from the bike although you know the pump is good. I know that you know the bike itself has power, so it's just a little breakdown in communication somewhere in between. What is between the harness and the pump? Whatever "it" is, "it" probably isn't working and should be bypassed or replaced...... As for the tach, make sure the signal wire is plugged in.

 

Hi.
My tach got weird after I melted the three yellow wires that go in to the rectifier on my 87- 750 vfr. I've replaced the wires, but now the tach show way too much rpm....

Could it be the CDI?

I am going to replace the rectifier too, even though it still works...

 

I have one that needs repair but how does one remove the circuit board from its box ??

 

I just repaired 2 ignition boxes.
Both had tiny crack rings around the main input wire pins.
That happens when they run the board over a solder bath.
Not enough heat gets into the large wire pins and its a "cold solder joint".
Just re-soldered with good heat and it started working again.
Also replaced a failed transistor in another one.

Heat the plastic box edges with a heat gun/hair drier and pull on the heat sink, should slowly release.

This guy makes replacements;
http://home.comcast.net/~tjhafner/V4-spark.htm

I'll be going through my collection of Gen-1 IGN boxes and check them all with a magnifier, checking or micro-cracks.

 

I was looking through that website where the Ray guy and Tom were selling their CDI boxes and I was not sure so far in my reading whether or not they would work for our 86 and 87 VFR700/750 bikes.
I emailed Ray to see if his ignition unit would play nice with the VFRs, hopefully I'll get a quick answer.
http://www.rae-san.com/