1998 Grizzly600 cdi

[Brent Mason]

Originally had my griz600 stop running and then wouldn’t start ! After testing all coils , valve lash , compression (115psi) and all tested ok I bought a used cdi . After cdi install it still wouldn’t start (no spark) ! So even though the stator , pulse/trigger and charge coils check within good range I decided to switch the stator etc ! It started but It is very unresponsive on throttle and acts like it is running in 2 Different spark timing ! With slight throttle it will take off good but instantly go into a very different running mode with no power like timing very retarded but it will switch back to running good for short period then bad again !  Since I replaced the stator and it started I then decided to install the cdi I replaced and it did the same thing ! Also I noticed the Used cdi I Took off had a capacitor that had swelled and extruded from the back of the cdi . I had always heard and I believed that when these CDIs go bad they machine will quit and will not run . Is that true ? I also checked the cam/valve timing and its ok ! Checked with timing light and it does fluctuate on idle ! I am thinking I have 2 bad CDIs . I also switched the trigger Coil wires and would not start then . Man , this thing ran good before and I am confused ! Video below may help !

Edited September 3, 2020 by Brent Mason

[davefrombc]

Have you  checked for a loose or corroded  connection ? There  may also  be a carb problem causing it to go  lean when you open the throttle .. Have you checked it for contamination, plugged jets or  a faulty diaphragm?

[Brent Mason]

Well took carb off and everything looked great on it ! Put back on and started but same misfiring . It did a big backfire and quit and wouldn’t start ! Put a sparkplug on plug wire and has good spark when cranked over so it could have jumped timing . Going to tear it down and check cam timing and everything . Things like this become a challenge to fix and I always seem to get them !! I’ll post later .

[Gary Korneman]

The rough running two timing modes got my attention.  I had the strangest rough running on my 06 700. Did it when I activated the 4 wheel lock.  Didn't notice indicator flashing when it did this at first.  Turns out it is supposed send erratic  signal to coils  as a rev limiter  while not fully engaged to protect itself.  Dirtiest running I have ever experienced.  As soon as it engaged fully the lamp stops flashing and runs fine.  I don't see how these engines could jump valve timing unless the chain and sprockets are worn beyond recognition.  Good luck.

 

[MarkinAR]

@Gary Korneman Makes a good point here.  I have seen a few ATV's that have a reverse rev limiter and sometimes that causes some really odd issues.  Might look into that and see if your machine had it and how to bypass it to rule it out.

[Brent Mason]

I don’t think there is a reverse limiter and I’m not sure there is a rev limiter at all on this old griz! As expensive as this particular cdi is used ones are hard to find . I am kind of amazed someone hasn’t tried an alternate cdi from a different model ? Timing advance may be the only hold back ! Most all the other CDIs I’ve studied have the basic stator/pulse/power wiring scheme . Surly somebody on here has tried a different cdi ?? 

[Gary Korneman]

you might check How to wire a gy6 on youtube  skip to about 8 min and you wont miss anything

cheap chinese cdi, 

 

[Brent Mason]

I seen that video and am considering doing that if after done doing rings , new timing chain it runs the same way ! Waiting for parts but the engine is in very good shape , no cyl ridge , checked valves and good , timing chain loose so we’ll see . Was a little worried that the chinese deal wouldn’t do the spark timing advance as I think stock CDIs do . 

[Brent Mason]

Well all back together and started ok but ran like crap still ! Took cdi off and it fried it just like the other one I had on it ! Is there anything that could be frying the CDIs ! In pics you can see where a capacitor bubbled and melted whatever the stuff is ! The other pic is the 1st cdi and it bubbled same as the latest one ! I spent hrs digging the stuff out to see what size the capacitor was but wrap on cap melted when using acetone ! I think I’m going to try the Chinese 6 wire cdi ! These Grizzly600 CDIs are very expensive ! 

[MarkinAR]

There are really only 2 ways to toast a CDI and that's a bad regulator or direct short somewhere in the harness. 

[Brent Mason]

I’ve heard that the regulator wasn’t in the cdi circuit on the Grizzly 600 ? 

Be nice to know what the 12 pins do on this cdi ? Not sure what to check for grounding . I know how to check trigger and charge coils . 

[MarkinAR]

How is the battery?  Seems like some of the Yamaha's use the battery as a capacitor, essentially lowering the system voltage to 12ish volts.  Without a battery or with a bad battery it may be dumping 14-17V into the system and burning components.

If the battery isn't the issue then I'd shuck the plastics and start running down the wiring harness from the battery forwards.  It's either a jump in voltage or a direct short to ground that's burning the CDI.  Curious though why it wouldn't pop a fuse if it's a direct short...

[Gary Korneman]

I just zapped another piece of electronic equipment connecting it hot, they wont tolerate arcing during hookup. knew better. Also the type capacitor you are looking at is an electrolytic.  Has the insulating material between plates  grown or etched on chemically. they wont tolerate reversed polarity, if that helps.

[Brent Mason]

I wonder what the specs are on that capacitor ?