HI guys hoping someone here can help me, my cb400 finally arrived from japan in October (2006 vtec spec 3) and due to work and weather I had not had that much time to ride it (I have done about 150 miles on it)

The last couple of rides I have noticed it takes longer to start with the choke out than my old bike would and it really bogs down for the first 5 mins of riding and has actually put me in a couple of hairy situations, a bit more info.....

my old bike was also a cb400 vtec although a 2000 model so spec 1 not spec 3 and had over 60,000 miles on it (I got it on 50k) and had been very well looked after its whole life but had whiney gears and generally looked a bit beat up.

I had experienced this on my old bike a couple of times but not as extreme as on the newer one, my new one has 9000 miles from new and is in near perfect condition.

could this be a sign that the carb needs looking at? once its fully warm it behaves perfectly but the starting issue and bogging down is making me think something might not be right.

I do believe my old bike had new carbs at some point so could this be the 13 year old parts just showing their age?

any info would be great thanks