Lately, my engine's been a bitch, it does the following: Start it cold, let it warm up for a bit, then head off. if i nail it through 1st, 2nd, then 3rd, it goes really smoothly through the rpm range to 14 where i change gear. If I start it warm and take off, it does exactly what i'm about to explain. It sounds like it's running on 3 cylinders, but if I back off the throttle until it's just on a little, it sounds like it's firing on all 4 again.then, as long as i'm below about 11,000rpm, I can ease the throttle on bit-by-bit until full throttle, and it sounds like it's fine, until i get to about 11krpm again. It's hard to explain, here's an example. I'd be cruising along at 80, give it a fistful, and it would stutter it's way to 120 or so, where it stops accelerating. Whilst it's at 120, it "surges". It's like the bike is trying to go faster, but something's holding it back. I thought it might be the air/fuel mixutre, but even after playing with the main fuel screw thing in the middle of the carbs, it doesn't help the issue. Is something blocking my fuel line? Is my air filter not clean enough? I took my air filter out over the weekend and gave it a cleanout. What makes me wonder, is this started happening all of a sudden, it wasn't gradual, so something's happened. Sorry for the vague explanation, any ideas?
sonds like it's not geting the fule it needs do you have a pump how much fule do you keep in your tank do you hav a fule filter if so is it bloked maby a tune would fix it all
Pretty much what Ace said. If you do not get positive results by checking/cleaning/replacing air and fuel filters, then it is time to move on to bigger and more costly things... lol This is the idle adjustment screw and will not help in this situation. I'm going to say Air/Fuel issue. Clogged filters and dirty carbs. Get'em synched too.
out of being a noob, and knowing what running out of fuel is like, i've come to the conclusion that i'm not getting enough fuel in. it behaved itself for a short time on the way back to work from home at lunchtime, got it up to 175 before i backed off. (was wearing a dirtbike helmet with no sunglasses = sore eyes from wind) when i get some time i'll clean out my fuel tank and fuel lines etc. and see if i can fix the problem.
I'll betchya it's a dirty fuel filter! I had just about the same thing, except mine would cut out and do it's " stutter" thing to the death, and if I let the throttle go, she would go instantly. Changed fuel filter, have had no problems of the sort at all! -Muzza
Interesting.... When you say the 'stutter' of death... what exactly would it do? I've been having a few little niggles with the big-daddy-FZR and it doesn't like doing bullet runs at the moment (wind on full throttle in top gear from 80km/h until... well yeah). I did give the fuel filter a bit of a clean but haven't tested it out since. Looks like i'll be going to that mystery top speed location again and giving it a shot.
well prettysure you're all wrong. mine was doing the exact same thing... its just gunna get worse and worse like mine did. 2 of my exhaust valves in one cylender were beggining to **** themselves. youll probably find if u compression test it one cylender will be alot lower on compression when it seems like its on 3. so yeh i'd say a couple of ur valves are starting to leak.. i could be wrong but thats what it was with mine... and when it cuts in an out from 3 cylenders to 4 i'd say its definately not fuel
2 points to Fzr3LN3. After re-reading the description mr_mordred provided i'd have to say i agree; but as it's really a worst case scenario lets hope it's not. When was the last valve clearance check done? When was the last compression test done?
no idea when either of those were done last, i don't know how to do them, and i don't know who can do them. sounds exactly like it does when it used to run out of fuel.
get a compression tester and test ur compression.. chances are youll find its down in one cylinder. if thats the case.. which it most probably is.. its probably your valves. if you cant pull your head off and check them yourself. take ur bike to a mechanic and get it checked. just to confirm what it is.. seeing as it seems to be cutting in and out its probably not the rings.
I don’t think this is a textbook valve problem. The main thing that stands out to me is the fact that it starts fine when cold and only when the bike heats up the problem arises. Usually when you have valve issues the first sign is having trouble starting the bike. Damn straight. KISS (keep it simple stupid) is usually the philosophy to call upon in such a situation. Also if you get the smaller things out of the way first it helps allot to trouble shoot more serious problems. Mr_mordred2095 what kind of fuel economy do you get out of a tank?
Yeah mine does the same thing at the moment, im sick of pulling engines apart n crap now though so im taking it somewhere to get them to check it out, after thinking it maybe a spark plug or lead problem, they have been changed but its still there, i think its something to do with the carbies, anyone know anyone in north of melbourne thats good with FZR's? Cheers, Troy
well last night i pulled off the tank and the airbox. flushed the tank out, i left the filter and pump attached and filled it with water, I sealed it at the top so it'd all come out the other end, and it was flowing quite freely, so that eliminates the problem of blocked fuel lines. when i pulled the airbox off, one of the rubber boots came off the carbies with it, no problems i thought, i'll just re-attach it. WRONG I spent 2 hours trying to get these little ******* rubber things back on, with no success. It looks like they're out of shape to what they should be, so i'm going to get another 4 from yamaha on the way home, because 3 of them won't go back on, and I want it sealing properly. The air intake of the carbs seemed pleasantly clean, but i'm not sure about the rest of them, I'll pull it apart tonight and take a look.
oh, and i'm getting ~150k's to a tank, partially due to the fact i hold it pinned everywhere i go (otherwise it's just so god-damn gutless with this problem). and it's not running good at all now, jsut runs like **** all the time, my nooby guess is carbies for sure.
yeah i have the same problem, except even worse, i get around 70k's to a tank i gotta keep it flat out on freeways to keep it going on 100. its a pain in the ass, i need to fix it or get someone to fix it...
70k's! ether someone is siphoning your fuel when you aren’t looking or your emulsion tubes are well and truly ovaled out. 150k's is a reasonable number if it is to reserve. Both sound very much like carb problems as you said mr_mordred2095.
