bogs and dies at low rpms

[Cognac]

got a 89 FZR 600.....bogs and dies and low rpms, seemed like the carb was flooding but rebuilt and cleaned carbs and still same problem

[Target30]

have you checked your fuel filter? or tank, migh have something clogging the filter or petcock that allows fuel through when there is higher pressure

[haunter]

fuel pump could be toasted

[apsolus]

will it idle? you cleaned the carbs really good? like the pilots and there ports? sprayed through all the ports and watched cleaner shoot out the other side? is everyting on your intake side air tight? no air leaks?

[ragedigital]

The Idle Mixture Screws (IMS) manage the idle/low RPM range. You may want to make sure that they haven't been adjusted too far out of the norm (usually ~3 turns out)

Have you had this bike for a while or is it something you recently acquired? The reason I ask is that if it's new to you, the first thing I would do is rip through the carbs. Find out if there is an after market jet kit on it, check the emulsion tubes, see what Main jet is in it, etc... These are excellent things to keep on hand while asking questions.

[sweekster]

Bogging usually equals rich to me. That can be attributed to out of synch carbs and/or incorrect float height. You said you cleaned the carbs. Do they have anything after market in them, whether it's adjustable needles or bigger jets? These are only guesses but some things to ponder and maybe help.

[thatkid]

Bogging usually equals rich to me. That can be attributed to out of synch carbs and/or incorrect float height. You said you cleaned the carbs. Do they have anything after market in them, whether it's adjustable needles or bigger jets? These are only guesses but some things to ponder and maybe help.

I'll add, have you replaced the air cleaner/filter?

[Cognac]

thanks guys.....checking all things....

this was recently acquired bike.....I bought bike knowing about the problem

thought carb had bigger jets but checked and everything is stock.....air filters are clean, fuel pump is good.......

checking electrical now....could be weak spark

[thatkid]

Ok when I bought my bike it idled rough, was difficult to start when warm, below 2.5k there was no power, over 3k the power kicked in. <<< classic signs of running rich.

After checking the ignition system & renewing the plugs, I turned my attention to the carbs. I adjusted the mixture screws, and gained a slight improvement on the idling. Next step clean/service and balance/synch the carbs.

The Jets were stock, the needle Jets were set @ the first clip position from the bottom (rich). After setting the needle Jets correctly (second position from the top) cleaning/balancing the carbs. Result!

I've read many posts saying stock needle Jets have no adjustment, I have 3 sets of European/UK carbs, all are stock and all have adjustable needles. I'm thinking the none adjustable needles are a Cali/US thing.

If you need to pull the carbs again, check the needle adjustments (if any) are set correctly and the float heights, stock is 22mm.

Good Luck.

[Cognac]

ok guys.....after 45 days....the culprit was the imulsion tubes were "jacked"...not perfectly round but "egg shaped" which the needles had alot of play which caused flooding....replaced the tubes and she is running TIP TOP!!! oh yeah!!!!

[kiki231]

haha-- i hear you --
mine were so bad the bike couldnt climb my sloped driveway without bogging. Factory Pro are mine, and i paid 125 bucks for all 4.

BTW, i will be posting a video on the emulsion tube repair i did back in July, along with the the work i did setting the float height.

My float height with my stock main jets is currently 20mm. I am running still slightly rich. I will be testing the mix by using my new "colortune" tool, which allows you to watch the colour of the ignition through glass spark-plugs. After running several different engine speeds, i should be able to determine if it is the float height or simply the mixture screws. BUt in either case, she will be DIALED.

[ragedigital]

If anyone else reading this read is wondering what "emulsion tubes" (needle jets) are, I have posted the images below. After a while they can wear and produce and egg-shaped hole which can cause a "rich" condition.

[apsolus]

ah so thata emultion tube, i thought it was the needles themselves, live and learn. seems like you can never kno everyting about carburators! i swear i learn a new sync meathod or butterfly this float height that all the time

[thatkid]

If anyone else reading this read is wondering what "emulsion tubes" (needle jets)

Dang, I thought "needle jets" was American Speak for what I call the "air valve (throttle slider) needle/s"

[DonTZ125]

No, those are the "Jet needles", which slide in the "Needle jets".