Low on bottom end power

Hi, I'm a long time Fizzer owner.

I've got myself a shiny bright orange 1988 FZR250 2kr model. I've had it for a few years now, i've replaced the engine with a second hand one. I did the timing on it, and compression test was ok. Engine runs fine, abit noisy on the timing chain side.

My carburetors have caused me the most problems. I have 2 carburetors, the one im using has new main o-rings and the best parts of the 2 carbs. I've synchronized the carbs and cleaned it out a few times. I've done the tube test and they are all around the line mark.

Clutch was slipping at high RPM after the first few rides, but no longer slips. engine had been sitting some years.

2 of my carbs 1 and 4 need the mixture screw turned to fully closed before the revs will die on idle.

Its not smoking, never seen blue smoke from it yet.

It idles alittle rough, starts only with light throttle work 1st or 2nd go, it sounds like its 20+ years old but gets me A to B. But I'm embarrassed to ride the thing.

Before I think about letting a bike mechanic look at it and charge me $XXX for telling me its old and a piece of crap, i'd like to hear some opinions or suggestions from other fizzer owners of what I need to try to get some better performance.

Problem: Seems to lack speed with its RPM, it only manages to 60-70 in 1st at 10,000+ and it doesn't feel responsive. I've ridden other old school CBR250's and they has good throttle response compared to mine. Other words it feels laggy, and have to wait for it to catch up.

Cheers!

 

Thanks Dave, does this chart apply to 2kr models with no EXUP? That chart seems in-line with what i'm getting on road.

 

motor is 87 i believe( i bought and put it in myself) but its defiantly an HX1 with 2KR frame with No EXUP, its registered as an 88, unsure why if what you say is true about 88 having EXUP. Both motors had the same lowish power at low RPM, would that suggest my carbs are at fault? the float needles have rings and some are sticking abit, could this explain the low power and running bad? I have another set of the same carbs, but I think all my float needles have rings and in similar condition.


If its not to much of a hassle what parts are different between the carburetors, all the idle jets have the same number but are they the same? and the float jets and floats all the same? which parts are different in 1 to 4th carb.

Thanks