Project A work in progress my FZR 250 2kr

This may sound silly, but put a cup (250ml) of Diesel fuel in half a tank of fuel and give it a hard run for at least an hour or 100Km. The Diesel will remove any 'gum' that is causing the rings to stick in the ring grooves, and may help with your low compression.

 

How long has bike been sitting before you started it?
Would suggest that a complete carb strip and clean making sure ALL passages are spotless and a Litetek seal kit would go a long way to solving your problems.

 

I reckon it's been tuned when it wasn't fully warmed up.
Once it's started and if you put the choke on what does it do?
If the rev's sit for a little then come up to 2000 or more, the mixture screw's might be close.
If it die's, then the mixture screw's haven't been adjusted correctly.
If taking the mixture screw's out then make sure you remove the spring washer and o ring from each gallery, hard/dry o'ring's wont help the tuning.
From memory the hole at the bottom of the thread's/gallery where the mixture/fuel screw goes in is either .13mm or possibly .3mm
You can get a micro drill set from someone like Jaycar and see which drill bit fit's, smallest is .3mm, i had to use a single strand of wire from a wire brush to open up mine to start with (.13mm)

@Joker had a good picture of the tiny hole in the bottom of the thread's once it's clean

When i first got my FZR it wouldn't start with the choke, you had to give it some throttle and hope it'd start before the battery would run out of kick.
After rebuilding the carby's with Keyster kit's (rebuild kit for carby 1 or 4, rebuild kit for carby 2 or 3) and setting the mixture screw's to 3 turn's out it won't start without the choke now (after tuning)
When i rebuilt the carby's, sync'd and tuned them i used a non contact temp gun to get a temp reading off the top of the header pipe's, and a home made manometer to get thing's all balanced and running right

There's some pic's in my FZR250 project thread

 

Kit B is for when you split the carbys into individual ones isnt it?
The extra seals (Kit B) go between each carby for float bowl vents and on the throttle shafts etc

I never split my carbys, and mine had done 53,000km's when i fitted the Keyster kits

 

If you are going to do it, why would you not do the whole job?
Get both kits and use a bit of lube when you fit the seals.

 

Just realised those Keyster kits i linked above are for the 3LN3 not the 2KR.

My bike budget didn't have enough money left for the Litetek seal kits, i just used all the new oring's and seals from the Keyster kits when i rebuilt mine
As it was the 4x Keyster kits cost me 20% of the original purchase price of my bike

Going the whole hog on the carby's could get expensive, buy the time you add it all up, new Litetek kit's A and B, new Keyster kit's x4, new slide's, new diaphram's etc etc