Help required - 4 Mikunis in line

[rossw]

I have a Yamaha FZ250 4 cylinder with 4 downdraft Mikuni's. Very recently it has developed a flat spot and a bit more vibration than usual. From my research I think balancing the carbs is a good (cheap) place to start. All the motorcycle shops I have tried so far are REAL unhelpful by saying that it won't be anything so simple, that there would be much more work required on the carbs or that they just wouldn't want to undertake it to begin with. Only one would give me some sort of estimate for it. I like to do as much of my own mechanical work as possible. Does anyone have any suggestions that will help keep the cost down?

[Taz]

Sell it and buy a late model 250 it'll be cheaper in the long run.

[TripleZee Dyno]

I have a Yamaha FZ250 4 cylinder with 4 downdraft Mikuni's. Very recently it has developed a flat spot and a bit more vibration than usual. From my research I think balancing the carbs is a good (cheap) place to start. All the motorcycle shops I have tried so far are REAL unhelpful by saying that it won't be anything so simple, that there would be much more work required on the carbs or that they just wouldn't want to undertake it to begin with. Only one would give me some sort of estimate for it. I like to do as much of my own mechanical work as possible. Does anyone have any suggestions that will help keep the cost down?

I am sure if you asked them to balance the carbs they would, its a straightforward job, but it sounds to me like you are asking them to fix a problem by balancing the carbs and they are saying there may be more to it and simply balancing the carbs may not fix the problem.
So just be clear on exactly what you want them to do, balance the carbs or fix the problem?
To keep costs down
Do the easy things first
check plugs
Do a compression check
whip the carbs off and give them a clean and a checkover,
if that doesnt work bring them in here and we can put them through the ultrasonic cleaner.
If the bike still has a problem, beg/borrow another set of carbs and try those
If all else fails you may have to bite the bullet and spend some money.
We can run the bike up on the dyno so its in its flatspot and then try and figure out whats happening, but that will cost money.
good luck