FJ 1100 backfiring and poor throttle response and slow rev recovery

[minitruckeratheart]

ok so i guess this is where i should be now. i have completely cleaned the carbs. reassembled them, and started the idle mixture screws ( the small ones on top) to 1.5 turns from shut. and the sync? screws the three in between the carbs to 2.5. it runs and idles but still popping and poor throttle response, and slow to recover to idle from rev. i did just add a fuel filter between the tank and carbs because the tank had a bunch crap in it from not having a gas cap. the pulse lines are disconnected right now, i will cut new ones tomorrow and hook them up where they go, i was told one goes to the tank and the other to the ign? maybe i didnt read that right, but if someone could post a pic of were the #2 line goes that would be awesome! are there some vacuum lines im missing or something? why would it still have a poor throttle response, and be backfiring? could it be in need of new plugs and wires? the manifolds between the carbs and jugs looked to be in good shape, not misshapen or cracked or anything so i would imagine they are not the problem... im about at a loss

[Flynt]

poor throttle response, and be backfiring?

You are not even close to synchronized on the carbs...  there's no "2.5 turns" rule for this adjustment.  Try this at your own risk (may lose some hairs on your fingers):

1.  Get running at idle with carb intakes exposed (tank off of course),
2.  Hold 3 fingers together with an 1/8th inch gap or so between fingers.  The most important thing is to do a repeatable spacing... keep that in mind.
3.  Place your 3 finger "gauge" over each carb for a couple of seconds, palm of hand away from carb.  If you can feel a difference in the flow (you'll be surprised, but you can unless the gaps between your fingers are too big), adjust it out with the balance screws.
4.  Sequence of adjustment is important...  3 screws and 4 carbs means you'll run out of screws if you do it wrong...  do the outside pairs first, then the inside pair (1&2, 3&4, then 2&3).
5. you have just done a course balance that will get you through to a decent running state (defined as off throttle popping, but no or minimal backfires).  
6. If it didn't work, try harder.  If you really can't judge the airflow at all, ask a friend to try.  Most people can "feel" their way into decent running with this coarse approach.
7. Now get a tool to help you dial in a fine balance...  you'll be amazed!

Frank

[Flynt]

BTW - you lose the hairs when it backfires from the cyl where your hand is...  can scare a little pee out of you the first few times as well, but never any real damage.

Frank

[SlowOldGuy]

The hose off the #1 cylinder goes to a vacuum petcock.
The hose on the #2 cylinder goes to a port on the ignition box.
The other 2 vacuum ports are blocked off.  

All 4 vacuum ports are used for synching the carbs.  The "2-1/2 turns out" on the synch screws has probably put you WAY off and any further adjustment without accurately synching the carbs with a proper gauge is just wasting your time.  I've never seen that in any of our instructions.  
1/8 turn on a synch screw is a SIGNIFICANT adjustment.  Randomly setting them as you've done makes any further tuning impossible.
Fix one thing at a time and move on from there.

Oh, and GET/BUY a MANUAL and start reading it!

DavidR.

[minitruckeratheart]

well i read somewhere 2.5 turns from seated. maybe it was the idle mixture screws... i dont know. i guess ill look into a diy manometer. not spend 100 bucks right now on one. ill try the course sync approach first. it was pretty dark when we got the carbs back together and oil back in and everything. just wanted to hear it run. ill have more day light on the morrow.

[fj11.5]

would of been the mix screws 2.5 from seated ,, should run much better with the vaccume hoses connected , most likely that's the crap response and popping , along with the synch

[minitruckeratheart]

HOLY $H!T guys! hooked up the vacuum, and did a sight sync, held the carbs up and set all the butterflys to have the same amount of light as the #3 carb comming thru the bottom. and WOW! let me repeat my self  WWOOWW   ITS RUNS AWESOME! gonna build a manometer soon and sync them proper, but for right now three days down and it went from uhhh r u sure it runs to hold on to your butt... I cant thank you guys here enough for the great info and help! this thing is way more then i expected! well worth the money. no to get it painted, and a head light. i think im about to pull the stock cluster out of the fairing and see if i cant mount it up some how, just til i get some aftermarket gauges.. but i guess that all needs to be in the mods section thanks again guys!

[Flying Scotsman]

HOLY $H!T guys! hooked up the vacuum, and did a sight sync, held the carbs up and set all the butterflys to have the same amount of light as the #3 carb comming thru the bottom. and WOW! let me repeat my self  WWOOWW   ITS RUNS AWESOME! gonna build a manometer soon and sync them proper, but for right now three days down and it went from uhhh r u sure it runs to hold on to your butt... I cant thank you guys here enough for the great info and help! this thing is way more then i expected! well worth the money. no to get it painted, and a head light. i think im about to pull the stock cluster out of the fairing and see if i cant mount it up some how, just til i get some aftermarket gauges.. but i guess that all needs to be in the mods section thanks again guys!

They dont run to good without the vacum lines hooked up.

[fj11.5]

run like they mean it when not sucking air they don't need, , what's wrong with the fairing, , trashed ,,

[minitruckeratheart]

yeah 1/2 was gone when i got it, the rest was broken in many places, poorly painted, or other wise not worth keeping. it looks much better now in my eyes. now thats not to say if it had all the fairing to begin with i wouldnt have tried to clean it up and just paint it. but i did kinda want a streetfighter anyways. now i have one. and i got less then 1k in a big bore super-bike streetfighter. thatll out run my buddies gsxr 750 down the street, and my bike dont even run right yet and its almost 15 years older! it pulles much harder then that 750. he said man that sounds like a 600, then he rode it. wow dude that things pretty quick. but more about the turn lights, i did away with the extensions for the turn signals and mounted them closer up to the frame. i cant even see the turn lights in front now the handle bars hide them. i used the bolt and mount for the front faring bracket and the rear drop bracket for the tail lights and they look better then just hanging out there in no where. im sure it looked better on a bike with fairing, but this one has no fairing... now... and im cheap, to cheap to buy some flush mount turn signals. not when i have working ones. now to get the gauge cluster mounted, i got it pulled from the fairing. im thinking just zip tie. but i dont know yet. maybe ill try and jb weld up me bracket... ya know i should call them and see if i can get them to sponsor the bike! ya ever heard the expression if ya cant duct it F@*K it. well i feel that way about JB WELD.

[fj11.5]

yeah I checked out the indicator   pics, look much better, but how did you mount the back ones so high, dousnt she have the covers below the seat , as they cover the original bracket top mounting holes , , for an older bike they sure surprise a few later bike owners, , spoke with a mate yesterday , sold his gsxr, , told him to buy an Fj , answer was what's that and who makes it , thought mine was a newer bike , one in my profile pic started out like yours in red and white , 84 ,, with trashed fairing, got sick if trying to repair it , couldn't find one at the time., , should be easy enough to mount the gauges ,, send an email to jb weld, telling them how much you use it, may send you some free stuff 

[minitruckeratheart]

the tail lights are mounted to the half hole that the fairing bushing was sitting in all fairings have been removed, fenders as well. brackets too. the bolt that mounts the lights is still the same one just cut down what 5-6inches. i think it looks much better and with a nice coat of krylon it will look killer. well with a round head light... the stock one will have to work for short time but winter is comming so ill have plenty of time for more mods. i just wanna ride. 2 more buddies picked up bikes recently and i feel left out.

[fj11.5]

should look great when your finished, , mind you they are never finished, ( 7 yrs ) so far , , how much was she mate, much better bargain once they run right

[minitruckeratheart]

700 bucks. worth every penny. very happy with it. im trying to talk my buddy out of his 2000 cagva gran canyon. he hasnt rode it in years and after coming back from iraq he hasnt been able to ride. but ill be happy with this one. maybe it will be the one i keep. i have owned a few and sold or traded them off pretty quick. 2 kantunas... one f4i and a shadow 750. i worked on all of them, but this is by far the most fun bike ive owned. and i really like the streetfighter look going on. my uncle says he has a chrome round headlight from a tractor i can have. i heard from a buddy that i could using scotch bright and panty hose for air filters. and i think im going to cut down the the exhaust. i have a plan with some steel wool for baffling for a little restriction. but thats all for the mod thread. when i get some pics of the bike with the front turns and maybe ill start a thread in the mods section.

[minitruckeratheart]

i have about 40 bucks in gas, hose clamps, oil and maybe a couple other things but the jb weld carb cleaner cleaning rags and all the other stuff i have used were laying around. so 700 for the bike +40 to get it running. i think im doing alright. get some paint make a manometer, and figure something out about a license plate holder all ill be ready to rock! oh head light and these gauges.