I need suggestions for a 96f3 with 500 original miles on it. It has a weird sounding like fouled plug almost or little bibbley stutter coming out of it at all constant rpm settings.
I though for sure it was plug driven, no. I thought next for sure from setting for a long time, years, it was in the carbs, took them off, spottless, all orfices seem clear spraying carb cleaner through all points. still same. If you hold the throtttle at say 3-4-5 grand, it just kind of stutters a bit and climbs and falls in rpm by a hundred or two back and forth also.
I'm going to check the vac next, but has anybody seen this happen when they where braking in their bike.
Thanks.

 

WOW, 500 miles on an F3? Not bad. Sounds like carbs to me. If they get gunked up, they will do exactly what you describe. Sounds like the intermediate jet. Idles fine, probably not the idle jet, runs fine under full acceleration, probly not the main jet, but part throttle yeah, that sounds like intermediate. Check em again, or run some fuel injector cleaner through your gas and that'll clean it out if it's not TOO bad.

 

well, I am syncing the carbs now, seem all at 7 in/ but getting too hot too really check perfectly, but initially looks good. The carbs were super dupper clean, no staining in the bowls at all, or debris for that matter in the bottom. I took out the intermediate jet, blew air and carb cleaner through, watched where it came from whn spraying in all the intermediate jets directly, i sharpen the end of the tube on the cleaner to fit in the hole where the IJ screws in, then spray and watch for it to come out of the other holes, would that tell me if it is clear?? I think so. they all did the same.
it idles a little bumbly too, it is very slight, but noticeable. I don't know what eles to look at, electrical? seems not, I don't even know how the carbs could get any cleaner. ??
hmmmm
oh yes, when it was first fired up after sitting, it ran absolutely perfect, for about 100 miles, then started doing this. That sounded like carbs for sure, loosening up debris etc. but like I said, there are NO signs of gas going bad in them, they usually show like a varnish stain, or worse crud in the bowls when that happens/

 

I also ran sea faom through it before

 

Last, carb sync doesn't help, still rpms unsteady, pulled a wire one at a time, unsteadyness stays same (minus rpm drop) I'm lost now.

 

YO, P !!!!!!!!!!! This is a genuine... GOOD ONE !!!!!!!!! Are the sync levels, all bounce'n at a idle, how about if you bring it up Slowly, to 1500r's... all come'n up evenly????? my first thought is loose intake manifold., to head/ to carb. spray abit of starting fluid or carb cleaner at each juncture, ya know ,while running. Were all needles seated evenly, on the top of the slides??? wierd things happen... seems unlikely... got a tight valve??? or maybe a chunk of carbon, on a seat. compresion test, wide open throttle,as "DAD" says... SEA FOAM additive, is getting rave reviews here... got a float level off??? or float valve sticky?????? pinched vacume line to petcock??? plugged gastank cap vent, listen for "whooosh". I agree... it sounds fuel, but could it be a sticky ignition advance ???? any whooshy sucky, chirping sounds, anywhere??? use a giftwrap tube and listen while pointing it around at exaust, intake junctures. Carb syncing tools(vacume gauges) are awsome diagnostic tools, to find all kinds of problems. Seems exstreamly baffling to have the prob. be genericly across all cyl., especialy after such a goood carb clean job... is a individual carb cocked, on the rack, and not pulling evenly, do they pop back in evenly ??? Cracked plug cap???? or bad connection to the cap????

OH, run a high volume fan into that radiator,for cooling, and tune away !!!!!!! I'll keep think'n(limited ability!!!!) keep us posted... you'll find it... HANG IN THERE, Blog "DAD", he's a genius !!!!!!!!!! Clean and free, Ripp'n

 

was that reply in english??? just playing rippn, you definately have a style all your own.

don't know if it's a possibility or not (i'm not familiar with the f3) but i had a similar problem with an atv that i bought that had been sitting for 4 years. cleaned and recleaned the carb, played with every linkage and hose and nothing. turns out that the fuel line coming out of the petcock had a slight crack (dry rot) in it and was sucking some air in when i reved it up. the fuel rate wasn't what it was supposed to be. maybe totally off, but it might be worth checking your fuel lines and make sure that all is well and connections are firm.

 

ok, let's see here. thanks for pitching in, i ususally can figure these things out by now, but no luck,...YET.
the bike has only like 500 miles on it, and mechanically it looks like it rolled off the floor yesterday.
I have a small snowblower gas tank that works great to give it fuel while tank is off, hook it right to the feed side of the pump, pump gives it's little kick every couple of seconds like it's suppossed to, no gas dripping out anyplace, bypasssed the pump once to hook straight in to carbs by gravity, gas flowed good, but no change in running.
I also ground the fan sensor switch to the frame when testing, put the trickle charger on the battery, and let the fan run prettymuch to whole time when tunning.
I don't know how to check the advance, but when the sensor on the carb is disconnected, the rpms drop a bit, that sounds like an advance TPS to me??
The plug wires have been taken offf the colis inspected and put back in with dielectric greese, disconnected the computer thing on the frame, followed plugs to check connections etc.
the vacuum is dead on on all clynders now, exactly 7" they are steady on the needle, but the needle won't show much sputter. They do all sound the same to the ear though, and all seem to cycle the same when the throttle is cracked open. though now it even has a hesitation building rpm too,when cracing from idle,, ESPECIALLY IF YOU CRACK IT OPEN SMALL AMOUNTS LIKE 3 TIMES CONSECUTIVELY, IT WILL ALMOST STALL?? gas gas gas it has to be!! When the choke is barely opened, the hesitation can be made to go away, and runns and exaust pattern sounds pretty smooth.
that's why I took off the carbs again, I can do it in 5 minutes flat now. actually it is really easy with a phillps that is 12" long for #4 & 1..... and one that is 3" for #2 &3.
Last time I didn't back out the pilot screws, now they are out. (to get them out and adjust them, i took a dremel wheel and carefully cut a slot in them for screwdriver use, works fine and doesn't screw, no pun inteded,.. them up) and I'm going to REALLY give them a cleaning this time.
I still can't beleive the carbs could have something in them, but who knows. I know for sure it's not a gas supply issue though.
out to the garage, you guys see the fastest indian movie, and features with burt munro,.. pretty good.

 

I've got a set of carbs ???
Interested...let me know!

MT
rdracer134@yahoo.com

 

Is all hope lost,...time to through in the towel,....let me keep messin around for a while, but I will keep you in mind for that, sh_t, I could sell these ones on ebay for brand new!!!