Odd 1997 FZ400 running issue.

[spencer_foxwell]

Hello.

My 400 takes a couple of seconds to start usually and when the weather is cold say below 5-6c it will take longer, colder and I may have to bump it. Once the engine is warmed up and ridden for 5 minutes or so it likes to drop a cylinder and then easily cuts out if I try letting it idle. If I stop and switch the engine off for a couple of minutes then restart it, it will fire up easily and given a bit of a rev it seems to clear it out? It then runs on 4 cylinders and generally doesn't give me any hassle or odd behavior for the rest of the ride.

Does anyone have any idea what could cause this?

I have changed the spark plugs and it seemed better at the time but the problem is my test day with the bike was a bit warmer so I don't think it would have happened anyway.

Cylinder 3 lead looks like it has a split as it joins the top of the black tube that goes over the top of the spark plugs (Please forgive me for not knowing the name of that... Caps?) Could that have anything to do with it? I've been using plenty of WD40 all over the shop to avoid moisture getting to it.

It will do it on a cold morning but hasn't yet done it on the way home from work, I assume due it the weather being a touch warmer by then.

Can anyone help?

[ChristoT]

It sounds like there are several problems there!

On the starting front, cold engines never like to start that much, but ensuring you have a healthy battery and clean carbs will help it.

As for the cutting out while riding, I remember a post coming up along those lines a while ago, and someone suggested that the carbs were icing up. The cold air flowing into the carburettor caused the carb to ice up, thus starving the engine of fuel. The engine heat would then melt the ice, and you could continue on. Can't remember the fix though, sorry.

Trimming your HT leads, and ensuring they have a good connection to the caps (yep, that's their name!) will certainly help too.

Good luck with it all, and welcome to the Foccer fold!   

[spencer_foxwell]

Ahhh right, you think it could be freezing? I wouldn't have thought it is cold enough outside for that?

Looking at another thread it seems replacing the caps solved a 3 pot running problem for them and also made me realise they come off the leads! That split I mention could just be the lead coming out of the cap I suppose. I'll have a look in the morning. How do they go in? Is there a connector in there that you have to push it home into?

Thanks for the help so far

[ChristoT]

Ahhh right, you think it could be freezing? I wouldn't have thought it is cold enough outside for that?

Looking at another thread it seems replacing the caps solved a 3 pot running problem for them and also made me realise they come off the leads! That split I mention could just be the lead coming out of the cap I suppose. I'll have a look in the morning. How do they go in? Is there a connector in there that you have to push it home into?

Thanks for the help so far

Not 100% sure, to be honest, I'm dredging up a memory of a thread - possibly on the 600 board? All I would say is you have cold air + wind chill factor coming in to a cold carburettor. Just sayin'.

Never done it myself, so can't comment. I believe it's a screw type adaptor, so you pull the lead out, trim it, screw it back in. A post asking for futher details in the General section should help more than my ramblings!

From what I understand, the 400 shares many parts with the 600. The 600 and general sections are also more visited than the 400 section, so if in doubt on something generic (like HT lead trimming), maybe try asking there if the 400 board doesn't help too much. 

[spencer_foxwell]

Thanks mate I'll pop a duplicate in there

[unfazed]

Drain the carbs as it sounds like water in the bowls. At night the water sinks to the bottom and it is picked up by the pilot jets when trying to start first thing in the morning and as we all know water does not ignite to well. Might be worthwhile next time the tank goes on reserve remove it and drain all the fuel from it and refill it with fresh fuel.
Unfortunately the 400 does not have a prime in the fuel tap making the draining the carbs a little more difficult.

[His Dudeness]

Drain the carbs as it sounds like water in the bowls. At night the water sinks to the bottom and it is picked up by the pilot jets when trying to start first thing in the morning and as we all know water does not ignite to well. Might be worthwhile next time the tank goes on reserve remove it and drain all the fuel from it and refill it with fresh fuel.
Unfortunately the 400 does not have a prime in the fuel tap making the draining the carbs a little more difficult.

Sounds logical to me. You could take the filler cap off the tank and clean out the drain hole as well as draining the tank and carbs. If the ht lead is split at the end near the spark plug you could unscrew the cap and trim the end of the lead. If you've been getting water in your carbs for a while they may need a clean