Fuel, air, spark, but no bang!

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Tommy
Posts: 7
Joined: Sat Apr 26, 2014 11:20 pm
My Bike: Kawasaki ZXR 400 L9

Fuel, air, spark, but no bang!

Post by Tommy » Wed May 07, 2014 1:29 pm

Hi guys

My ZXR 400 L9 model won't start any more. When I first got it, it was a bit of a pig to start. Full choke, bit of throttle and a couple of attempts at cranking and it would go, but this morning it was having none of it. Looks like a day in the garage then.

I checked all the plugs, they looked fine. Had a tan colour and was a bit wet (meaning there was fuel going in). I cleaned them, tested for spark and chucked them back in. All good.

Tested the fuel pump anyway, cranked her with the pipe to the carb out and spat fuel out of it. Nothing wrong here. Put my hand over the carbs while it was cranking and it was sucking the air like it should.

Now what's left to check is the carbs, timing and valve clearances. They should all be fine though as the previous owner had the carbs cleaned and balanced by a garage, as well as the clearances checked. I can't imagine any reason why the timing would be out. I also checked the battery for good measure. It was at 12.4v with the bike off, and dropped to about 10.6v while cranking.

Have to say I'm at my wits end here, no idea why she wont fire up! She runs perfectly when warm.

Thanks for reading, hope one of you can help me :smt010

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banner001
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Joined: Sat Sep 24, 2011 3:27 pm
My Bike: ZXR400 L4
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Re: Fuel, air, spark, but no bang!

Post by banner001 » Wed May 07, 2014 3:39 pm

12.4V is low for a battery at rest, should be up over 12.6V at least, try charging the battery and then turning the engine over immediatlely after disconnecting the charger, see if that makes a difference.

if its always been hard to start, and your sure its not electrical its probably the carbs, what pipe/air filter/downpipes/main jet/float height/mixture screw combinations have you got?
UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

Tommy
Posts: 7
Joined: Sat Apr 26, 2014 11:20 pm
My Bike: Kawasaki ZXR 400 L9

Re: Fuel, air, spark, but no bang!

Post by Tommy » Wed May 07, 2014 3:49 pm

Do you think the voltage is low enough to give ignition problems? If so I'll have to go out and buy a battery charger.

I couldn't tell you much about the carbs, I haven't had them apart yet. There's only nearly 15k miles on the clock and the owner liked to keep everything standard. It's got a standard pipe. If charging the battery doesn't do anything I'll have to have a crack at the carbs.

Tommy
Posts: 7
Joined: Sat Apr 26, 2014 11:20 pm
My Bike: Kawasaki ZXR 400 L9

Re: Fuel, air, spark, but no bang!

Post by Tommy » Wed May 07, 2014 6:08 pm

Okay! Got her started, sort of. Got her to fire up with full choke and some throttle, but the bike would only stay at about 1,000 revs, and I had to keep the throttle about half way to keep it there or it just cut out. Very weird, no idea what's going on here.

The battery wasn't holding it's charge too well, I got it well above 13v but I could watch it drop. Regardless of what's wrong it needs a new battery.

Tommy
Posts: 7
Joined: Sat Apr 26, 2014 11:20 pm
My Bike: Kawasaki ZXR 400 L9

Re: Fuel, air, spark, but no bang!

Post by Tommy » Wed May 07, 2014 6:11 pm

OK no worries, I backed off the choke a bit and she's running like a dream. Thanks for the help Banner, I'll take it from here :smt004

Tommy
Posts: 7
Joined: Sat Apr 26, 2014 11:20 pm
My Bike: Kawasaki ZXR 400 L9

Re: Fuel, air, spark, but no bang!

Post by Tommy » Mon May 19, 2014 1:38 pm

Little update on this, found the O rings on three of the float valve seats were knackered which caused my engine to flood while it was parked. Found this out after testing for spark and getting sprayed with petrol from the cylinder.

I've ordered the Viton seal kit, hopefully I wont have to wait too long for it confuddled

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banner001
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My Bike: ZXR400 L4
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Re: Fuel, air, spark, but no bang!

Post by banner001 » Mon May 19, 2014 1:53 pm

glad you got it sorted, its always the carbs :D
UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

Tommy
Posts: 7
Joined: Sat Apr 26, 2014 11:20 pm
My Bike: Kawasaki ZXR 400 L9

Re: Fuel, air, spark, but no bang!

Post by Tommy » Mon Jun 09, 2014 7:48 pm

Bike's been fixed for well over a week now, changed the seals all over and changed the oil twice with a new filter the second time. Bike's fixed! Been riding everywhere on it and it doesn't miss a beat.

One thing though, the choke doesn't work the way I expect. I normally start it with a bit of choke and throttle because it won't start with full choke. Once it's started adding too much choke will kill the engine, as will adding too little. So I have to put the choke into a sweet spot where it will idle nicely until it's warmed up. I'm guessing it's running rich but I want to make sure it's not something else I can check before buying a pilot adjusting tool (want to see how the idle reacts to pilot screw change.)

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