NC23 Spluttering/OverFueling Issue need advice on please

[darin]

HI

I have had many 2 strokes and only a few 4 strokes with this my first CBR400 NC23 I bought recently which it was standing for a while. I stripped down the bike cleaned the carbs out few times over, gave it a service, new oil, filters, fuel pump realy as that was faulty and new plugs.

Since that it has started first tick over without even using the choke or giving petrol and it seemed to drive really well. I took it out for its first proper drive this weekend doing about 100KM in distance. It drove perfectly at first but I noticed when the bike warms up and gets hot it starts to almost splutter and feels like it kind over fuels when driving. (Temp gauge doesn't look like it is overheating at all). This only happens when its riding at normal driving speed. When I floor it and rev it out, it runs perfectly. I notice the silencer can is very very black. I'm not that clued up on what the problem can be so hoping for some advice in fixing the problem?

Any advice on this first time CBR owner?

Also side comment, I am thoroughly impressed with the bikes speed and handling. Coming from a 2stroke fan that is saying something :)

[dunkenb]

May be the o rings on the fuel/air adjuster screws are starting to perish?

[darin]

Where would I be able to check that?

[dunkenb]

If you look at the engine side of the carb the air/fuel screws are there,unscrew them fully and you'll see the O rings on the screws, you'll be able to see if they're perished ( usually they come out in bits as they'll have been in there 20yrs) Give em a clean and get new O rings from Graeme France , should sort the over fuelling

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