Everything You Need To Know About Carburetors

[moey]

how do you balance the carbies i dont think they showed it is it screws or do i have to tac them apart

[DEMORAL1ZE]

HEY yamaha where is the "well documented" sticky on carb cleaning..............thanx DEMO

[ALMOST]

I have taken lots of pics of the process, but I didn't think anyone would be interested. I was going to make a pic/video. I will put it together and post it.

[DEMORAL1ZE]

yaaaaaa.......

[ALMOST]

I have lots of photos, give me a day to put them togther on photobuck and I will post what I did. I took them all apart and dipped them.

[moey]

hey its me moey again wif the fzr 250 3ln1 1990 model uuum i just got my bike back from the work shop they cleaned and synkd my carbies and not it foes hard but there is one problem before it didnt go over 10 thousand rpm and it go to 13 or 14 then cuts of again and they told me it may be from the head or my eletrical wires are bad what do you think its from my bike goes hard but when it goes over 13 or 14 rpm the powers drops cheers.....

[yamaha_george]

hey its me moey again wif the fzr 250 3ln1 1990 model uuum i just got my bike back from the work shop they cleaned and synkd my carbies and not it foes hard but there is one problem before it didnt go over 10 thousand rpm and it go to 13 or 14 then cuts of again and they told me it may be from the head or my eletrical wires are bad what do you think its from my bike goes hard but when it goes over 13 or 14 rpm the powers drops cheers.....

M,
I have no idea what the rev limiter is set to on the 250 version that may be why she will part shutdown on ignition at that point.

Since 13000 up is with throttle virtually fully open you may need to check the size of your main jets in the carbs. Once you know what size you have you can compare that to stock sizes and buy a set that is a size OR 2 bigger.
Personally I would buy a size larger & a size smaller and go ride and see if the bigger size helped or not if not I would go to a size smaller & see.

Do you know any track racers / tuners might be an idea to make a friend and see if they will "loan" you a set to try & get the bike working on loaned jets until you get it right then buy the guy a new set of jets and a good bottle of his favourite drink

[DonTZ125]

George - redline on these little beasts is 18500; limiter is probably 19500.

Moey - I'm having probs reading your posts. What I gather is - yours wouldn't go past 10k; you had the carbs cleaned and sync'd, now it pulls hard to 13 or 14k then breaks up. Is that right?

What's your fuel level in the carbs?

Is your EXUP properly adjusted? It may not be opening properly.

Check your charging system; I get the impression that ALL the fizzers have high-rev issues when the VR or generator starts konking out. Definitely check your wires and plugs.

Have you checked your ignition timing? If the flywheel has become advanced (missing woodruff key?), you'll lose top end revs, but have good punch down low. (Factory Pro sells an advancer but it's 'only' 5 degrees)

[yamaboy]

Hey Ragedigital
Here are some things that could make the Wiki: Everything you need to know about carburetors golden:

Adding to table of contents: Checking/Adjusting float heights , Needle settings, Jets chart , Synchronizing with a Laser Gun , Reading spark plugs.

Checking and adjusting carb float heights. I came across somewhere how to adjust the floats with a credit card and also an invisible ruler. Just so you don't have to pay $50+ for a float height gauge from factorypro . I believe 24mm was the optimal height if you have a jet kit but can't remember. Also pics on bending the tab for adjusting the floats.

Another thing would be a little info on what setting to adjust both the factory pro needle as well as the dynojet needle based on different applications. For example , K&N air filter , slip-on exhaust , 3 settings from the top for the factory pro needles,stage 1 or configuration 10. Individual K&N air filters with a full exhaust ,_ settings from the top of the factory pro needles,stage 3 or configuration 30.

Another example:
"Factory Pro needles at #2 position with the little washer under them
Stiff Springs
117.5 Mikuni (small round) main jets
3 turns out on the mixture screws
Floats at 23.5 mm"

Also info on where to start with the air mixture fuel before fine adjusting . Example , turn untill screw is all the way in then _ turns out? Same with the fuel screw. Maybe a chart with jet screw numbers and what to use for different applications. I believe I have 107 and 52.5 jets.

Also a link to this would help http://scooter.wikia.com/wiki/Tuning_a_carburetor

Just some ideas