Kwaka GPZ400R fuel Problem

**nezumi** · 8th May 2006, 13:54

Hi all,

I have a GPZ400R which wont run. I can start it up with the choke easily enough (the choke seems to work just fine), but when I try and blip the throttle it chokes and dies every time, you can hear the air get sucked through, but it just wont fire on it.
I have already checked my valve clearances, and had my muffler off to make sure that it wasnt blocked. The fuel tap seems to be flowing fine, and the vaccum on it is working. I havent measured the compression, but it feels alright on all 4 cyclinders. I also had the carbs off and blew air through them, they were quite clean and didnt have any bulid up of dirt in them.
My next thought is to dissect the carbs (which I've never done before) and have a look around.

Anyone have any ideas or had a similar problem before??

Thanks, Joel.

**imdying** · 8th May 2006, 14:22

What happens if you crank the idle up quite high so that when you come off the choke, it's still revving pretty high?

**nezumi** · 8th May 2006, 16:50

The idle has to be right off to start, it wont start with it on (even a little bit). If I try to screw it on while its running it just dies in the same manner as opening the throttle.

**imdying** · 8th May 2006, 17:01

Fully ghey... blocked pilot (slow running) jets?0 Some of the fuel comes through the main jet on the choke and off idle, so maybe when you turn the choke off or blip it, it dies cause it runs lean when it tries to use the (blocked) pilot jets? Motu?

**nezumi** · 9th May 2006, 09:01

Yes i see.
So I pulled the carbs off last night and cleared out the jets, but didnt get the opportunity to start it, that will have to wait til after work. Heres hoping!

**imdying** · 9th May 2006, 10:15

Stab in the dark mate, don't get your hopes too far up! On visual inspection, did the pilot jets appear blocked? How about the mains? Much crap in the float bowls?

**nezumi** · 9th May 2006, 17:09

They were pretty clean, no build up of crap in the bowls, but It looked as though a previous owner had siliconed the bowls back on, and over time a few bits had come away and were like small pieces of rubber skin floating in the bowls. But there werent any pieces small enough to get inside the jets.
The main jets themselves were pretty clean, but a couple of the pilots were a bit blocked, so i gave them all some air.
I also had a look at the diaphragms and they seemed fine.

**smokeyging** · 9th May 2006, 18:50

It's not electical is it?,whats the plugs look like? are they black, wet or dry. did this slowly happen or did it happen suddenly? has the bike been idle for a few weeks? is it sour fuel? try the simple things first.

**nezumi** · 10th May 2006, 10:58

Still wont start, has the same problem.
I pulled the plugs out a couple of months ago, before I knew I had a prolem (I got the bike damaged a couple of months ago and it wasnt going). The plugs looked ok, but I dont know how old they are, so I am going to replace them this week.
I know the bike has been sitting garaged for a couple of years, but I have new fuel, water, and oil in it.
I really dont think its an electrical problem, Its starts too easily and will run alright on only the choke. But like I say, Im gonna replace the plugs anyway.
As far as I know, it was running right up to when it was crashed (before I had it).

And thanks for the help guys, its much appreciated.