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Guys,

I'm having problems with my H1 ZX and I'm not sure where to begin. I got the bike from a pal who hadn't run the bike so I changed the spark plugs, oil and coolant. It starts fine everytime but reuns really badly when I open the throttle. If I'm riding around town at 30-40 mph and only slightly open the throttle, it behaves ok. Anything spirited and she protests big time.

I put some redex in the tank and went out for a good run last weekend. It managed to stutter to 70-80 mph on the motorway and went fine (couldn't get more that 80 out of it thouth) for about 30 minutes when I reached my destination. The return trip was the bad one. It was sputtering badly and eventually slowed to 50mph when I had no choice but to get off the motorway. The bike cut out as soon as I stopped. I decided to give myself and the bike a break for 5 minutes and tried it again. It started no problem but had hell to idle. I got it running and took the back roads home. It was still running very badly but it got me there in the end.

I parked it up, went into the house and came back to the bike after 15 or so minutes. There was a small pool of pertol on the ground which had obviously come from the bike.

My initial thoughts on the whole thing was that there is a problem with the ingnition system but after seeing the fuel on the ground, I'm thinking it might be the carbs.

I'm thinking about stripping the carbs and cleaning them. Is there anything in particular I should watch out for or do maintenance wise (I've never done this kind of thing before). The bike's got a race can as well and I have no idea if the jetting has been adjusted to suit. What's this whole Dynojetting thing I hear so much about anyway?

Cheers,
Charles.

how long had it been sitting for till you got hold of it? It could very well be the carbs gummed up with crystalised fuel. Fuel usually pours out when they have flooded, so a bit of gum could have come loose and blocked a float needle open.

If they are gummed up, when you get them apart itll be like a gritty jelly (thats what i had once on my moped) in the bowls and this blocks all the jets. clean as much of that out as you can, get the jets out and clean with a toothbrush, dont use a needle to poke through the jets as you might damage them. It'll be worth getting a couple of cans of carb cleaner to make a proper job of it. Also give the fuel filter a clean if it has one.

Stick em back on and see how you go

Dynojet kits are simply different sized jets and when you add a sports can that affects the fuel/air ratio, so you need to adjust this accordingly with different jets. Hope that helps mate

as RobB says sounds like fuel has gone off, my dad had it on his gpz400 strip the float bowls off, clean em with a tootbrush and carb cleaner, you will be amazed at the results, i personally wouldn't mess with the jets at this point.just a quick clean does wonders!

Well, she's still running like crap. I took the carbs off and cleaned them up. It has certainly helped because when it's not missing, it runs pretty smoothly. The only thing left is ignition and that's where the party really starts and I start grasping at straws. So where do you begin with this sort of thing?

There are 4 brand new spark plugs in it so what's next? I looked at the HT leads and they look fine, no corrosion and none of them are brittle or visibly damaged.

Any advice would be greatly appreciated.

Cheers.

what does the exit from the exhaust look like? if its full of carbon deposits then it'll be running too rich. have you checked for good sparks from all the plugs?

Oh yeah, she's defo running rich. I haven't pulled out the spark plugs after replacing them so I'm not sure what they look like. How can I check to see if I've got a good spark from the plugs? I used to do a lot of work on single cylinder bikes but I'm a novice on 4-pots.

just whip each plug out one by one and rest them on the engine and turn the engine over checking for sparks, if its weak it'll either be HT leads or bad earth.

Cheers dude. I'll try that a bit later and get back to you.

I think she's fecked. Left work for home and she died. Very suddenly as I slowed down for a stop light. I noticed the revs dying to nothing between every gear change shortly before it cut out. So there I was, in traffic, in the middle of the road. I pushed the bike to the side of the road and tried starting it. The started motor wizzed away an the engine turned but nothing. Dead.

There was plenty of petrol in it so it isn't that. What can it be? Coils? Can they just stop working? The bike is now home but I'm not sure if it's worth the money to try to repair the bike. It's an H1 '89 and probably worth very little. I've spent a couple of hundred on it to get it through it's MOT but I'm loathed to spend a lot more money on it. The brakes hardly work either so there's more cash involved in fixing that as well.

So what do I do? Fix or scrap? Is it coils or something more serious?

Advice?

Thanks again.

Hi,

Have you checked over the choke and it's assembly. With petrol on the ground sounds like the carbs are flooding resulting in overflow. This would also cause your bike to chug/cough/splutter when acelerating (mixture too rich as said above) & also cause the engine to die at idle when engine is hot.

Rob.

yeah if the carbs are flooding the plugs will be getting too wet hence the naff firing, if you have fuel on the ground then i would suggest the floats are sticking.

All I can suggest is that as well as cleaning the carbs out and making sure the floats and needs move easily. I would remove the float and you will find the flaot valve seat. Theres a little rubber o-ring that had gone brittle on my bike and was causing petrol to get past - even with the float fully up.
A set of 4 seals was something like £6.

Mine sounded like it was only firing on 2 or 3 cylinder while this was happening + its a fire hazard.

Dont get rid of it cos these bikes are great.