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Hi everybody,

I'm new to the forums and qutie new to riding. I am in need of help though. I have been riding since about the end of March, have had a great summer, but now the weather is getting a bit worse my zzr600D (1990) seems to have great difficulty starting up from cold.

History:
Got the bike from a mate of a mate, sorted its electrical issues, ran it without any trouble for the last 4 or 5 months. Would always start up after a couple of seconds with 1/2 choke and maybe a tiny bit of throttle (or "gas" to the Americans reading this... just in case there's a language gap there), clutch in, on sidestand or centerstand, lights off to ease load on battery, but didn't really matter.
On one rainy day (not quite the first one, and not especially cold), it refused to start at all, nor on the next day which was dry. Eventually jump started it after much cranking and choke and throttle then replaced the battery. Also checked the spark plugs (slightly sooty, but not massively, so cleaned them off), and made sure that every plug got a spark (held a plug against frame when in each HT lead and observed that it sparked for all 4). Drained the float bowls in case some crud had got in there, but all that came out was fuel.

Symptoms:
To start it takes a clear minute at least of cranking over (it cranks at a good speed), full choke and a chunk of throttle too (I have tried all levels of choke, and resting in between in case I had flooded the engine). Once it starts to fire I still have to hold the starter button for about 5 seconds before the revs take off and I can let the throttle off, then it's about 15-30 seconds before I can take the choke back down to about 1/2 (where it always used to be for starting anyway) and let it start warming up (adjusting the choke appropriately as it warms).
Once the engine is at running temperature it'll start with no trouble if I turn it off and leave it for up to about 2 hours (maybe needing a tiny bit of choke/throttle if left over an hour, but that's expected).
Initially I thought it was a problem with damp getting in, but we have had 2 days of clear warm weather here and it's still being a total pain.:(

Theories:
So far I have been told it might be...
*dirty needle valves in the carbs
*carburetors icing up due to not having the carb-warming pipe attached at the moment (broken pipe, replacing that tomorrow, but seems unlikely since temperature hasn't got below freezing, or even close)
*HT leads breaking down so spark not going through spark plug
*poor compression (there is no clearance on my inlet valves, but all the exhaust valves are within spec, and it runs well when warm so I don't think that is the issue)
*lazy batter (but it is new, checks out with a meter, and starts fine when engine is warm, so i don't think that's it either)


Any help you can offer would be greatly appreciated as I need my bike to commute to work (and for fun at the weekends of course:D), and I don't want to hammer my battery with 1 to 5 minute starts every day. Thanks in advance.

Hello
:-Lightinthedark
 

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I'd think it's carbs myself, probably need a good cleaning or even servicing on a bike of that age.

Carb icing can happen several degrees above 0, but it occurs when riding from what I know of it, as ice forms due to the pressure change in the airbox, so even if it was below 0, it wouldn't be that.

Try running some carb cleaner through it, BE SURE to adjust the amount of cleaner you put in there to the same ratio it would be in a car, or you might melt the rubber in the fuel system (ie a whole can for a car's 60 liter tank is way too much for our 15-20 liter tanks).
 

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Welcome Lightinthedark.
Had a friend with a VFR400 which had the same problem.
The bike needed full choke and No gas (dont touch it) to start first time, she was doing the same 1/2 choke and gas, full choke and gas and was flooding the engine.
When you took the plugs out did they stink of fuel?
She just needed to "get to know her bike"
Good luck ride safely.
 

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Discussion Starter #4
Thanks GreenEnvy and lbknuckles.

GreenEnvy:
I have put some "fuel system cleaner" (basically Redex but without the brand name) in the tank a couple of times recently; used only 1/4 to 1/3 the amount the bottle said because, as you say, my fuel tank is smaller than a car's. I really hope it's not the carbs as that'll be a nightmare of a job... think I'll take that as a last resort (which may come very soon)

lbknuckles:
It used to only need 1/2 choke and little/no "gas". Now it only fires on full choke and high throttle. I really have tried not giving it any throttle across the entire choke range. If I had never managed to start the bike easily, then I would agree that my starting technique could need examination, but since I have had to change from what always worked easily to a way that eventually works usually (and the old way no longer does), I would say it's a fault that has developed with the bike.
The plugs were dry and very slightly sooty. There was no "stink of fuel". Thanks for the suggestion though.

Just to update you (and anyone else that may be able to help): The last 2 days have been warm and it has been starting a lot easier, but still harder than it always used to be, and I just know that as soon as the sun hides away again and the rain comes it'll be just as much of a pain as before.

My dad has offered to buy me a set of HT leads, so I'm gonna see if that helps (it can't hurt anyway even if it's nothing to do with my problem), and I finally got the part I need to re-connect the carb warming tube. I'll let you know if either of these makes a difference, but in the mean time if anyone has any more ideas, or even an "oh I had that, it was ... " moment, I'd greatly appreciate your input.

Cheers guys

Hello
:-Lightinthedark
 

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Discussion Starter #5
So, I covered up the bike last night (using an old waterproof jacket of mine), and it completely refused to start this morning. Tried it when I got home (after a warm dry day) and it fired up without too much trouble, but still nowhere near as good as before this trouble began. I'm still stumped, and would really like someone to give me an idea or 2 before I embark on cleaning out the carbs on a suspicion.

Any suggestions are much appreciated.

Hello
:-Lightinthedark
 

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You need to check the choke circuit on the carbs to make sure it operating as it should.
Have you got a manual?If not - get one it will save you loads.
Not ht leads as that would effect the engine pretty much all the time.
As Greenenvy said stripdown and clean em.
No easy way im afraid.
Shame your no closer to Herts as i have a good video you could borrow on the stripdown of carbs, you be surprised how straight forward they can be.
Goodluck
 
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