Help ZXR250C - Won't start! :(

Flick the kill switch a few times or take the switch block off and clean it with electrical contact cleaner. Put the bike in neutral, stand up, pull clutch to eliminate any of those circuits.

Make sure the battery is fully charged.

If no luck try a roll start... get going and into 2nd gear, as you release the clutch, bounce on the seat so the rear wheel doesn't skid from compression lock.

 

Ive had them massive backfires through the exhaust & it wouldnt start, turned out to be the plug leads. They would show good spark when checking them over but were not firing properly when put back on the plug, all caused from the lead being broken off from the boot. Are your leads solidly attached to the boot or just pushed in? Just check your got the right leads to the right plug also.

 

My thoughts based on what you have said:

**potential cause of loud bang**
First off, like Sharky says the order you put your coil leads (if wrong) can cause mixture to ignite on an exhaust stroke which causes loud bangs but I presume you where facing problems starting before you started messing with the ignition?

**What I think the route of the problem is**
Another cause of "popping" when trying to start the bike (in my experience) is when the exhaust headers have become loose, not only will this exaggerate noises but also causes misfires/popping along with serious trouble starting!

**Other possible things that could be exaggerating your problem**

Idle speed screw - if this screw is turned too high you wont be able to start the bike, it would be like trying to start the bike with the accelerator at full throttle (the solution to this issue to to completely back the idle speed screw out *just dont back it out so far it falls out* and crack the accelerator just a pinch when trying to start

Intake leaks - Apart from what I was saying above about exhaust leaks intake leaks can be troublesome, check the carb boots for leaks etc.

Petrol contamination - If your tank has been contaminated with water it doesn't matter how clean your carbs are, try ditch the petrol and empty the carb float bowels and put some petrol in you know isnt contaminated.

Oil level - Oil that is over full is bad, incorrect oil viscosity is bad etc etc get the oil right.

Also check if a clutch start works.

End

 

Good maintenance tip, but you said you had spark so id be looking elsewhere.

 

note the disclaimer in the previous pose
"My thoughts based on what you have said"
I mean if we are just ignoring his hear say then I think he just lost his keys and there is a rat in cylinder 3.

 

fuel tap on ? vaccum line connected ?

Carb boots okay ? sometimes they crack when pulling the carbs off.

 

Spark can test OK outside the cylinder and even on a spark gap tester, but still fail to work in combustion chamber conditions.

 

Hmm. You've tried testing for fuel to the carbies but what about fuel to the cylinder? I'm leaning towards fuel. Get an eye dropper and drip a few drops of fuel through the carbies directly into the cylinder (hold the slide up) and try again. If she fires almost starts you might have an issue in fuel flow somewhere, I know you said you rebuilt the carbies but you never know. Sometimes you gotta think root cause "what have I changed"? gets difficult when you change more than one thing I guess.

 

Whaaada ya mean bad spelling! I was totally talking about my previous pose, I have a pose for every post I swear #model

 

What I meant in my earlier post & something to check tomorrow, make sure the leads are attached securely to the boots(dont pull too hard), they shouldnt just easily pull out.Also, those boots actually screw down onto the plugs. Who done the comp' & valve clearances? With 80000ks on her hopefully not some dodgy on a Friday arvo.

 

What voltage are you getting from the battery? I've run a bike on fuel that is a year old and it worked fine.