ZX9R 2001 misfire when cold

[Ninja900Ben]

Hi all
I have had my 2001 ZX9R Ninja from new but it has recently been giving me a bit of trouble, it is completely standard engine wise, expect for a Yoshimura RS3 can. The can has been on almost since I purchased the bike and it has run fine with it on so I dont believe this is the issue.
When I start the bike it splutters and sounds like it is missing on 1 cylinder and sometimes you need to open the throttle very slowly to increase the revs or it just dies. After 10 seconds or so, the spluttering stops and it sounds like it is running on all 4.
I noticed this more last winter, especially when it was quite cold. Starting would be a lot worse with the spluttering and it would take a lot longer for me to increase the revs without it dieing. I also noticed that on motorway journeys in winter, unless I kept the revs fairly high 6-7k upwards then it would stutter before accelerating when I opened the throttle.
For both these problems, starting and running badly when very cold, using a higher octane unleaded (super unleaded) seems to relieve the problems a little bit.
I read other forum posts and someone suggested an airleak. Does this sound like my problem? If it does, where is air likely to be leaking? I am guessing somewhere around the carbs but need some expert opinion to help get me started.

Thanks in advance to anyone who views and replies.

Ben

[StarGate]

Sounds like it's in need of a basic tuneup but primarily in need of plugs. When was the last time it had complete tuneup? Have you or do you use fuel additives like seafoam? What is the history on the bike along the lines of maintenance?

[Ninja900Ben]

Hi StarGate
I have kept up with the maintenance schedule through my nearest dealer, I am pretty sure they did them all right as it was a friend who worked there and he used to do it after hours for me whilst I chatted to him to keep him company. I have now moved 80 miles away so need to find another trusty dealer, but that's another topic. I have never used any fuel additives. I don't know when the plugs were last done but that should be listed in the schedule shouldn't it, I could change them to be sure they aren't causing an issue, they wont cost too much. hmmmm... how about split fires or whatever the latest plug technology is now do they make much difference? Its been a while since I checked.

Ben

[StarGate]

Plugs in a bike don't stay in long enough to warrant using the iridium or platnum tip. I'd just stick with the NGK plug that your bike calls for. I like to run a tank of gas with seafoam mixed thru mine once or twice a year just to keep the carbs clean. That and plugs would be the first thing I would do since it's cheap and you can do it yourself and either solve your problem or eliminate that as a posibility. It's easy to do and and might save you some expense of taking it to a dealer. Mine will have symptoms similar to what you described when I need to change plugs. It misses when cold and at low rpm's but as I get out on the road and "blow the soot" out just winding it out in each gear it gets better and better until it's running normal. After that it will run normal for a while. If I don't change them out for a while after that then it gets harder and harder to get them firing agian till eventually it has a constant miss.

[Ninja900Ben]

That sounds like good advice and a sensible place to start. I have looked for Seafoam and it looks like a US product, I cant see it available in the UK. I will pop down to the nearest dealer this weekend, grab some new plugs and some carb cleaner for the fuel, I will get what they say is best from their range. Thanks for the help, I will let you know how it is running early next week.

Ben

[Ninja900Ben]

Hi Stargate
I changed the plugs this weekend, just got the standard NGK plugs. I will let you know if it is starting better at the end of the week when I have had a few days testing.

Ben