Odd 1997 FZ400 running issue.

[spencer_foxwell]

I put this is the 400 section but this section might be right for what I need


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 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?

How does the lead join into the cap? As the split I mention might just be the lead coming out? Can I just shove it in or?

[Bracechenko]

Sounds like carb icing to me. Plenty of threads on here about this so hopefully something useful has already been written for you

[spencer_foxwell]

Thanks very much I'll look into that

[ChristoT]

Sounds like carb icing to me. Plenty of threads on here about this so hopefully something useful has already been written for you

Hey Spencer, is now a good time to say "I told you so"? :P

[spencer_foxwell]

Haha I'll eat some humble crumble to find the reason my bike is messing about :P

[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.

[darrsi]

Read the "Hesitatation, surging and crap mpg" post, and look what i wrote lower down on page 2.


If the carbs are similar to the 600's then i'd imagine that the carb heater circuit pipes may be clogged up as well.

[spencer_foxwell]

Fantastic guys thanks it definitely looks like it's carb icing I'll grab some of that alcohol and check my radiator pipes.

[Dave48]

Also to rule out electrical probs do something about that HT lead. 16 year old bike-leads must be tired by now-covered many times on previous posts.
Be systematic in your approach-look at one thing at a time. Electrics, carbs, heating pipes, fuel system. Good luck!

[darrsi]

Fantastic guys thanks it definitely looks like it's carb icing I'll grab some of that alcohol and check my radiator pipes.

It's not so much the rad pipes, it's metal piping that goes around the actual carbs that have very small waterways and they get easily clogged up, and there's also a couple of rubber pipes that are quite fragile as well.
The booze will help though. (for the bike, not you) 

[spencer_foxwell]

I had a look on youtube for a little video about it but found nothing? Does anyone know of a guide to tell my noobness what to do? I've got one for the clutch (which needs changing) 

[Olly]

If you ever fill your bike up at supermarkets - stop!

Yes they have cheaper fuel but they also don't sample the fuel, or change out the filters, as often as a mainstream garage does.  This leads to more water getting into your tank.  I had a 'mare with my trails bikes for exactly the same reason.  This doesn't seem to be a problem for cars or bikes with larger engines (1000cc+) but it plays havoc with smaller capacity engines.

It also lowers the working life of your filters drastically - for all engine sizes.

When you drain out your tank and your carbs I'd recommend changing the fuel filter as well...

Sorry I don't have a video link but you should be able to get a PDF download of the servicing or Haynes manuals.