2000 GSXR no spark after spark plug change | GTAMotorcycle.com

2000 GSXR no spark after spark plug change

1

1978550

Active member
Hi Everyone. First off, im no mechanic, im the first to admit that, but I am trying to help a friend who knows even less than I do and is broke. The Bike is a 2000 GSXR 750 stock. Owner was riding it when it died and he notice wire burning smell. So he got it towed home to investigate. Noticed the Reg/Rec unit and connector block was fried. Melted the connection block. So he replaced both and the bike would still not start. So he brought the bike to me. Upon arrival of the bike at my shop I removed all plastics, tank and airbox to unveil a wire that was disconnected under the seat. Reconnected it, installed airbox and tank and re tried it. Nothing. So I noticed the battery was dead and hooked it up to my charger. The next button push, the bike fired but was running very rough, almost like it was missing on one cylinder. So I shut it down, and checked the spark plugs. All the center electrodes were melted and very rough across all 4 cylinders. At this point I could tell the carbs were getting fuel. So I replaced the spark plugs with new plugs thinking this will solve the issue, but after installing brand new plugs, I lost spark across all 4 spark plugs. I checked every safety switch on the bike and replaced the CPU with a known working used unit. Still no spark. I get the proper voltage at the coil packs but don't seem to be getting spark at the end of the spark plugs. This seems very odd to me. Does anyone have any suggestions or tips from a similar experience?
 
First thought would be a problem with the plug connection (eg ball head when it should be thread or vice-versa or tight wires that need some muscle to seat properly on the plugs)

I am assuming the new plugs are the same model as the old ones, just not melted? Did you check the gap before installing?
 
Id take it to someone else to fix, that bike doesnt even have carbs.

Sent from my SGH-T989D using Tapatalk
 
That's great help fellas. The details about the carb/No carbs are irrelevant at that point. How about offering up some helpful advice rather than be a ****** about it. I already said I am no mechanic. I am just trying to help a friend whos down on luck and broke. Anyone else got some decent advice? Keeping in mind I now know its fuel injected.
 
GreyGhost said:
First thought would be a problem with the plug connection (eg ball head when it should be thread or vice-versa or tight wires that need some muscle to seat properly on the plugs)

I am assuming the new plugs are the same model as the old ones, just not melted? Did you check the gap before installing?
Click to expand...
Thanks Greyghost, I def checked the gap as per manual and seated the plugs correctly.
 
you will need to check the electrical, since it seems it burned up pretty good, so all wires need to be checked all connections, all fuses. Check the coils, the leads, the caps, on the leads you can hopefully remove the caps, snip off a 1/4 inch and reattach the caps, make sure they are on tight and on the spark plug seated snugly as well. to check for spark, remove one at a time, with lead still attached and plug on and touching some part of the bike cylinder head etc, crank the bike and and look for spark, move onto the next one.

just some thoughts....

.
 
Thanks for the decent reply GateKeeper. Appreciated. I definitely know how to check for spark and have the proper tools for it. No need to use the engine block but I have done it that way. I usually work on older bikes and have never even seen a crotch rocket with its plastics off, so I had no clue it was even fuel injected. I will do the things you say and check over the entire electrical system for any problems. It just seems weird to me that it had spark and fired before the plug change. I have already checked and tested almost every switch or electrical device on the bike so maybe it is a wire somewhere. The only thing I couldn't check was the signal generator and cpu. Special multi meter with peak voltage recording is required. But I replaced the cpu with a known working one and nothing changed. Its going to take a whole lotta investigating to track this one down.
 
check wiring harness for bulges or black spots, melted areas, sometimes the wires burn within and will not be seen until the external wrapping is removed. check the start/stop button make sure it's working correctly and not shorted.

Check your ground wire/wires

I like to use tools but the best way to see if one has spark is to look at the plug, if I see spark when cranking her over I know it's working.....it's a visual thing...LOL

double check all connections and make sure they are snug, perhpas some dielectric grease might help as well
 
Great! will give it a good once over. I was hoping not to get into the nitty gritty of the wire harness but I am almost out of places to look. I will focus on the coil area and around the plug leads and caps. The Start/Stop button was my first place to look then the ignition switch, kickstand switch, clutch switch and inertia switch. I probably tested every safety switch on the bike 4 times now. With them on and off the bike. All seems to be good on that front. Everything works, I even get fuel pumping. I am only missing spark to fire. Thanks for your help GateKeeper
 
so are the coils getting electricity ? and are they producing electricity ? they are fed from the battery, there should be wires going to them check for electricity at that point, what voltage is showing at those wires ? should be the same as what your battery is at.

Fully charge the battery, check to make sure you're getting full voltage to the coils. Weak spark can make bikes act like they get no spark at all, so you can see spark and still not have enough spark to make her run
 
Last edited:
Yup coils are getting power. Same as battery 13v on a brand new YUASA battery. I will double check the connections around the plug leads and caps this weekend. Gotta get this POS out of my shop space so I can back to working on bikes I know.
 
pull off the caps, snip the lead by a 1/4 inch or so and screw them back on, make sure the caps are in good working order as well and are seated on the plugs good and tight, some plugs require the small screwed on part others do not depending on the cap itself

that's all I can think of at the moment...

best of luck
 
Many electronic ignitions don't like to be checked without the plugs grounded and if you check this way it could fry the electronics.
 
plug was definitely grounded. I used something similar to this device to check the spark. You plug it into the spark plug socket in place of the spark plug and connect the other end to the engine block ground. It shows you the spark with a proper gap.
 

Attachments

  • modern-spark-plug-tester.jpg
    modern-spark-plug-tester.jpg
    39 KB · Views: 6
What type of plugs came out? What type did you put in?

Working on older bikes you should know about resistance plugs and non-resistance plugs. Could be your answer...
 
NGK CR9E came out and brand new CR9E went back in. Those are resistance type plugs. And yes I am aware of them. Thanks for the reply.
 
Update: The bike is now running fine. I took GateKeepers advice, cleaned the ends of the plug wires and screwed back on the plug caps. They didn't look melted, but for some reason It fired up almost right away after reassembly. I gave it a good test ride and checked over the charging system and all seems fine even though the P.O. did the install of the new reg/rec. Thanks to all for the replies.
 
You must log in or register to reply here.

Back
Top Bottom