Only running on 2 cylinders

[Kovey]

93' with bender quads, crank welded at 90degrees.. She died back in 2000, and has been sitting in basement since. Spark on 2 cylinders, switch wires around and can get other side to spark.. Wires going back to CDI box have continuity, so it has to be the CDI..

Anyone know who has any of these?? I'd like to get it going again.
THanks, Kovey

[vmax4sean]

Check ebay.com , and denniskirk.com ... They should have what you need

[Master of Faster]

Check the classified section on this forum, I believe there might be a couple. Also, I'm pretty sure I just saw one on eBay.

Here's one for a 92, $25. Not sure if that's different from the 93-94's? Someone will know for sure.

http://cgi.ebay.com/Yamaha-1992-Vmax4-CDI-Box_W0QQitemZ7192908341QQcategoryZ26356QQssPageNam eZWD1VQQrdZ1QQcmdZViewItem

[Kovey]

thanks, but I believe I can't run a stock box as it has the quad pipes on it. Need a used aftermarket, or to find someone who can still make a new one..

[Master of Faster]

aahh yes, I just read that you had Bender quads,sorry, those are the high rpms ones correct? 9000rpm?

[AL P]

could`nt he use one off a 95 or newer?

[snowrdr]

can someone better explain the quads and cdi thing. thanks

[racer7x]

Sounds like a bad coil to me, not the cdi box.......

[Skinner]

rev limiter, rpm of pipes

[Master of Faster]

Sounds like a bad coil to me, not the cdi box.......


He switched the wires and the other coil fired...

[YAMMIEGOD 3:16]

DUDE, DOUBT ITS CDI ANYWAY. THAT DON,T INTERMIT SPARK. WHEN THEIR OUT SLED WILL BE DEAD. ITS COILS. THE ONES GOING INTO SPARK PLUGS. AND GO TO YAMAHA FOR THESE OR GET USED. NO AFTERMARKET ELECTRIC JUNK LIKE DENNIS KIRK, PARTS UNLIMITED. etc. !! 3:16 (tony)
SNOWRDR, VERY SIMPLE. QUADS HAVE A RPM RANGE WHERE THEY MAKE PEAK H.P. AT, MOST RUN AT 9000-9200 ON 750. THEY HAVE REV LIMITERS IN STOCK CDI AND WITHOUT CHANGEING CDI FOR HIGHER RPM, YOU CAN,T RUN PEAK RPM TO MAKE H.P. !! 3:16 (tony)

[racer7x]

Did he switch wires going to the coils, or the plug wires coming from the coils ?
If he switched plug wires its coil, or wires going to coils to me would sound like a broken wire in that area. Never had only half of a cdi box go bad.

[Master of Faster]

Did he switch wires going to the coils, or the plug wires coming from the coils ?
If he switched plug wires its coil, or wires going to coils to me would sound like a broken wire in that area. Never had only half of a cdi box go bad.


I assumed that he switched the wires going to the coils because he said he'd checked continuity through the wires back to the CDI. I've never had a CDI go bad on a sled yet, but I do know that you can't check them, just replace them, I agree I've never heard of one going only partially bad before.

[AL P]

What rpm does a 800 cdi go up to?

[racer7x]

Coils are cheaper to buy than a cdi...LOL

I forget which side it is on my 92, but one of the coils is the same part number as the coil on the 88-90 Exciters I've had..

[racer7x]

750 is 9000 and the 800 is 10000 rpm rev limits..

[firemanharry]

Bad Coil. CDI should either work or not work like Tony said.

[Mtnmax]

Kovey, I had the same problem. C.D.I.'s seldom go out on the v-4. I worked on sleds at a Yamaha dealership and have all the electrical test equiptment. My problem turned out to be the charge or source coil. This is not a frequent problem, but I have seen it more than once on the big sled. You'll have to replace the stator. They run about $350.00 at your Yamaha dealer. If I can help anymore, let me know! MOF is correct. You can not check a C.D.I. You have to check everything else, and if everything else checks out, you replace the CDI. I am assuming that the wires you switched were the wires between the CDI, and the external coils. I am assuming that you got both external coils to fire. If this is not the case let me know.

[BLUE STREEK]

IF it ends up being your stator I have one of a 92 750 I will sell if that any good to you.

[toydoc]

If it is your CDI and you do have 90deg fire.
This is just what your looking for, plus it will plug right in for ya:
http://www.vmax4.com/vbulletin/showthread.php?t=149

[Kovey]

thanks for replys..

I did replace coil back when problem first happened,and still same issue..

there are 2 hot wires coming from cdi, each going to a coil. Continuity is good on both wires from cdi to each coil, so shouldn't be a wire issue.

when testing, i get right 2 cylinders to spark, then I switched the 2 hot wires (the wires don't mate up, so used alligator clips to hold them together) and now left side fires, right doesn't. So this shows that both coils are functioning.

Beleive me, I'd rather not buy a new CDI, but don't know what else to do..

[MadMax-4]

Hey Kovey

Did you check the resistance of the wirers, i'v seen in sum cases the where the continuity was good and the risistance was out of wake that means the wirer is partialy broken on the inside of the protective cover.
Also you can trye checking the stator resistance.
Just my .02
MadMax-4