Weak intermittant spark

[digitaldan]

My bike keeps running on three or four cylinders, last time around the fourth cylinder stayed down normally it would come back after some riding. I allready cleaned the carbs, set the floats and replaced orings. I took out all the plugs which has less than 200 miles on them and checked for spark. It's almost non existent, this goes for all of the plugs and leads. Sometimes a spark will come through then dissapear again. Same for both coils and ht's. I grounded it on the engine and the bike back fired which gave me such a fright I ended up with the ht plug cap in my hand ! I take it it's normal for them to screw / plug out ? I checked the the earth points for the coils and battery both were fine. Anyway I'm dont' know where to start, CDI, HT's, new plugs again, coils, pickup from magneto ? I have never ever had so many troubles with any other motorcycle  Such a pity as I rate the motor highly (when it's running) but as for the rest of it my goodness 

It's a '97 VVT model if it makes any difference, anyone have a simular problem or should I just get the matches 

[gsxr400 racer]

you have typical issues of a not so sorted B4 and  on such a fine purchase join the rest of us. Best bet for anyone wanting to keep the bike by some real plug wires that have molded plug caps...solves some issues and saves some time in the long run...If you dont plan on keeping it and have no patience torch it now for god sake torch it LOL I will never sell mine unless someone coughs up 10 grand...    phat chance so i will keep

[digitaldan]

It's Japanese, supposed to be reliable. Suzuki builds thousands of bikes with no problems, what the heck happened to the B4's ! The faults are so complexs it can be one of ten things or a combination thereof. I think all B4 riders are a bit cuckoo or are suckers for punishment :)

[PitterB4]

There are lots of posts here about similar problems.  Most are fixed, like Jay said, with new caps/leads.  Next most common I think would be a bad connection to the coils.  Just pinch those stupid spade connectors...  If those don't work, search around here. 

They are finicky bikes for sure...

Good luck!

[digitaldan]

Ok tried more things. All the lugs and connectors make good contact. The battery seems to run down quickly. To get the bike started I removed the headlight and tail light fuses yet the battery can still only give me seven or so goes on the starter. I charged it again and it gives 12.5 V but when I hit the button it drops to 10 V or less althought he engine "seems" to spin over fine. I measured at the coil terminals and get no more than 5 V or so. So now I'm guessing battery, pickup coil, regulator ? I have no spare battery to test with, should I be able to get spark with 10 V cause I'm still getting very little if any.

[digitaldan]

More info, charged battery again. Only one ht lead/plug has spark on it. Using the same spark plug on the other leads gives no spark. If I'm correct if one lead fires the other one should too ? Charging battery again then I'll swop the sparking lead to the other coil outputs and check again.

[digitaldan]

More info, charged battery again. Only one ht lead/plug has spark on it. Using the same spark plug on the other leads gives no spark. If I'm correct if one lead fires the other one should too ? Charging battery again then I'll swop the sparking lead to the other coil outputs and check again.

[tomacGTi]

You should be able to ohm out your leads and determine whether or not it's the actual wires or the plug ends themselves that are bad. The manual should also tell you the values to test the coil.

Each lead of the coil should fire when it gets the signal. Meaning, the pair should fire.

I would check:

-wires
-plug ends
-coils
-pick up at starter cover

Barring that, test a good known CDI on your bike. The caps could be getting weak internally and doing this as well. Also make sure the rec/recg are putting out the correct voltage. This also goes for the generator and batteries.

Less than 12v in the ignition system is no good.

[digitaldan]

Thanks will keep you guys posted, may help someone fix their problem too. I had the manual somewhere but it seems to have gone awol. Can anyone give me the ohm rating for the leads ? Thanks.

[tomacGTi]

With a multitester set to 1ohms for the coil and 1k for the plug ends:

-From + to - on the coil: 2.5-3.8

-From plug end to plug end: 30-50k

-Signal generator: set to 10 ohms: 80-120

Tests for the generator and RR are in the list already.

-Randy

[digitaldan]

Will the battery alone be able to produce spark if the RR and generator is faulty / unplugged ? Also can I put 12 V on the coil terminals to test the coils / spark ? So far the signal generator checks out at 115 ohms. I'm gong to try and get hold of another cdi.

[digitaldan]

I think this bike is cursed ! Finally after not getting any spark took the cdi to the shop where I bought my B4 from as they have a couple of Bandits standing around. So the one mechanic goes to the back with my cdi and moments later I hear a bike burst into life. So my cdi is fine, almost dissapointed I say thanks and head home. I decide just to get the thing back together as the bike parts make it almost impossible to fit my car in the garage. I put the cdi back in pour some fuel down the carbs and reconnect all the spark plug wires and spray a shit load of quick start into the carbs. Pressed the starter and voila bike fires up ! Almost in disbelieve I take a plug out to check and I now magicly have a spark so strong it jumps about a inch and onto the cylinder  Nothing except taking the cdi out and putting it back in and the bike standing for 2 weeks changed at all. Rode it and all is fine, I'm selling before it packs up again. Thanks for the help guys and good luck with your B4's 

[pmackie]

I'd be thinking you had some corrosion on the terminals...??

[daveberry]

hi if ya cant find ya manual their is one o this site at the top of the page on downloads if that helps