1996 VFR750 odd no start - PLEASE HELP!!

I'm pretty sure it's the control unit. When the control unit is removed from the circuit and the fuse is plugged in the bike cranks really strong. As soon as the control unit is plugged back in and the kill switch is on the fuse blows.

Are there any tests for the control unit to confirm?

 

page 259 (16-6) of the service manual

 

Also, how to decipher the code on my control unit?

Mine says:
MZ7A EC
701D
5614

I have seen EC and AC on the first line, I know to avoid ones with the "MZ7AC" in this line (California emissions bike). What's the difference between EC and AC?
Almost every CDI on eBay looks like it has 701D in the second line if the first line is EC, and 703D if it's AC - I'd guess they are not completely interchangeable.
The last number seems to be different on all of the boxes - I was guessing that the 2nd digit was the year of the bike, but this is not always the case...

edit: looking at the RC30 website for identifying CDI boxes, the last 4 digits represent the production date. In the case of my bike, 5614 represents that it was built in 1995, on June 14th = 1995 6 (June) 14(day). The chances of finding another CDI that matches mine exactly are slim to none.

 

Then, bike probably overcharged lithium battery, spiking voltage really high, destroying battery and ecu.

I have no idea how one is supposed to use a lithium battery in a vehicle without also a special charging circuit.

 

This is my problem, why install something in a bike that it was never designed for? Sure, they are very light and very cool but I'll take my chances with a lead/acid battery.

 

This is for testing the wiring, not the unit itself. I have already confirmed (independent of the manual) all of the continuity bits of that test. I am fairly confident that I don't have a wiring problem at this point.

 

I've already gone through 5 lead acid batteries in 7 years, I was intrigued by the longevity and cranking power claims of the LiFePo4 battery.

FWIW, I was also in Vermont during that time - a riders anti-paradise. Riding season was measured in days, not months. My batteries were removed in the winter time, stored indoors, and trickle charged periodically, but always failed prematurely.

 

no tests you can do with a dmm, you need a scope. get a used ign control module

 

That was my thought as well. Too bad that it's:
1.) relatively expensive
2.) a risk buying a used electrical part
3.) can't be tested to confirm it's bad, or tested another unit to confirm it's good...

It sucks that it was destroyed by a failure of a battery that I put my trust in because I didn't trust lead acid batteries any more.

 

Best batteries on the market these days are AGM, I'm using Motorbatt ones and they are very good. I may have dreampt this but I though somebody here a month or so back had worked out how to repair these CDI units

 

Everything that I have read suggests that a dead CDI is a paperweight. Like I mentioned above, I did test the wiring harness going to the CDI. All of those tests did not show a failure (and attached switches like the side stand and neutral switches) worked as expected. The front two coils measured correctly at 3.1 ohms on the primary circuit.

If anyone has a known good CDI I would be greatly appreciative. I trust you guys more than some random dude on eBay...

 

Hey didn't i bet it was gonna be the control unit...And isn't ebay that place where squids try to unload their broken motorsickle parts? Dealer or salvage yard before ebay for this one would be my bet.

 

I just contacted Shorai to see if they might assist financially with a CDI replacement.

 

i hope they help ya out VT

 

No reply from Shorai. Go figure.:rant:

I just ordered a used CDI from a reputable cycle salvage place in Michigan. They had a video of the bike running and driving around the parking lot - so that gives me hope that it's not a paperweight like my current CDI. I ordered it this morning at 8:35, and got the notification that it shipped today at 10:30.

So far, so good.

I wanna ride again!! :vtr2:

 

Kennybobby was right. The original CDI was shorted internally. I got the new CDI in the mail yesterday and got it on the bike during my lunch break today. It did not pop the fuse when the kill switch got switched to 'run' which was a huge relief.

The bike had no gas, so I did not start it. However it cranked really strong so once it's fueled up it should start.

 

Bike is running again...

 

Good to hear.

Did you ring them both out, so that we know what to look for, next time?

 

....................:thumb:

 

Do you mean check the pinouts on the good and bad units? No...