ReBorne Posted June 16, 2008 Share Posted June 16, 2008 Hi people! On a whim I bought an FZ400RL from a friend a few(!) years back. At the time it was a bit silly coz I didn't even have my full bike licence. Anyhoo, got that in 2002, but due to life's unexpected twists and turns it never got on the road. Though out of boredom I did strip it down, spray and rebuild it, replacing a fork as necessary in the meantime. Now I've managed to dig it out of it's corner in the garage and spend some time on it. It's fully ready for it's MOT and looking less shabby than it did. But it keeps cutting out. Starts - no problem, sounds good. Ticks over quite happily. Goes out riding nicely. BUT after about ½-¾ mile, just when she's getting warm, when I slow down and then try throttling back up she just chugs.... it's like she's not getting fuel. She cuts out..... and won't restart. From car experience it sounds like fuel starvation, but she has petrol in the tank. Leave her 5/10 mins to cool down...... she restarts. Take her back out - same again. Now, this is going to make me sound both stupid and ignorant..... but when I resprayed her I didn't take note of what position was what for the fuel tap. I've currently got her in the fully-anticlockwise place. Is my own stupidity causing the problem? Any ideas? Cheers! (",) P.S. Been looking round here and it seems like a great place to be hanging out!! Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 16, 2008 Moderator Share Posted June 16, 2008 Hi people! On a whim I bought an FZ400RL from a friend a few(!) years back. At the time it was a bit silly coz I didn't even have my full bike licence. Anyhoo, got that in 2002, but due to life's unexpected twists and turns it never got on the road. Though out of boredom I did strip it down, spray and rebuild it, replacing a fork as necessary in the meantime. Now I've managed to dig it out of it's corner in the garage and spend some time on it. It's fully ready for it's MOT and looking less shabby than it did. But it keeps cutting out. Starts - no problem, sounds good. Ticks over quite happily. Goes out riding nicely. BUT after about ½-¾ mile, just when she's getting warm, when I slow down and then try throttling back up she just chugs.... it's like she's not getting fuel. She cuts out..... and won't restart. From car experience it sounds like fuel starvation, but she has petrol in the tank. Leave her 5/10 mins to cool down...... she restarts. Take her back out - same again. Now, this is going to make me sound both stupid and ignorant..... but when I resprayed her I didn't take note of what position was what for the fuel tap. I've currently got her in the fully-anticlockwise place. Is my own stupidity causing the problem? Any ideas? Cheers! (",) P.S. Been looking round here and it seems like a great place to be hanging out!! Hi reborne, good to see you taking an interest again, boy its took a long time to get over that Tomos ordeal On your fuel tap, is there a prime position, if there is try that, you may find three positions, prime, reserve and normal. fuel taps are often vacuum operated these days (thats another story). Prime position will run fuel down to the carbs directly even if the vacuum tap is not working properly, If it works ok in that position and then konks out in normal or res, then vacuum tap not working properly. BTW if it is a vacuum tap you will have a fuel line and another line going to manifold somewhere Link to comment Share on other sites More sharing options...
ReBorne Posted June 16, 2008 Author Share Posted June 16, 2008 Cheers, oldgit. lol.... Okay, the tap DOES have a pipe going to the manifold too, so yeah it seems to be a vacuum one. Trouble is, I don't know which of the tap positions is what thanks to the respray.... :-( Even had a quick scout around a few bike shops at the weekend, but the only bikes I found had the taps with the metal tabs instead of the plastic knobs and they have the positions stamped into the metal. Hmmm. In retrospect a better idea. lol. Dunno if it's any good, but the pic shows the tap without the knob on it..... in a vertical position with the stop right round at the anticlockwise position. Once I know which is which, it should help troubleshoot the way you suggest :-) Cheers again! M. (",) Link to comment Share on other sites More sharing options...
ReBorne Posted June 16, 2008 Author Share Posted June 16, 2008 Dur. Try again with the pic. (Where's the "gun to the head" icon when you need it?) *Time Passes* Erm..... maybe I come back when I've got the intelligence to add a pic?!? Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 16, 2008 Moderator Share Posted June 16, 2008 ok, if you pull the fuel line to the carb very very slowly, if fuel comes out youre in prime posn and if not, turn the tap to other positions until fuel comes out. Note this posn and turn back off. Replace fuel line on carb, switch to newly found prime and start. run bike and see if it runs consistently without probs. Then try the other posns to see if it konks out Link to comment Share on other sites More sharing options...
ReBorne Posted June 16, 2008 Author Share Posted June 16, 2008 Sweet :-) Thanks! Have to be after work tomorrow, but I'll give it a shot! (",) Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 16, 2008 Moderator Share Posted June 16, 2008 If you do find the prime position, you should not be running the bike long term in that position. There is a simple test of the vacuum tap operation, turn tap to other positions than prime, take off the pipe from the manifold and suck on the pipe, fuel should then flow if working correctly, Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 16, 2008 Moderator Share Posted June 16, 2008 Dur. Try again with the pic. (Where's the "gun to the head" icon when you need it?) *Time Passes* Erm..... maybe I come back when I've got the intelligence to add a pic?!? Open a photobucket account Upload your pictures there With each picture you will see four fields Copy the IMG field Paste into forum Link to comment Share on other sites More sharing options...
ReBorne Posted June 16, 2008 Author Share Posted June 16, 2008 Oh, wow..... you CAN teach an old dog new tricks. Lol. And thanks again!!! Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 16, 2008 Moderator Share Posted June 16, 2008 Nice pic but...Means zilch to me, sorry, but at least you know how to now Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 16, 2008 Moderator Share Posted June 16, 2008 Check this out, from a FZR forum http://www.fzrarchives.com/ipb/index.php?s...&hl=petcock http://www.fzrarchives.com/ipb/index.php?a...lite=%2Bpetcock Link to comment Share on other sites More sharing options...
R1evad Posted June 17, 2008 Share Posted June 17, 2008 Hi There ReBorne, something else to consider when testing your fuel system, esp. as you say the bike been resprayed. Have you unmasked the breather pipes / holes to vent the tank again. If you run a bike, (or any engine come to that) you have to replace the volume of fuel drawn from the tank with air, or you will create a vacuum in the tank and (especially with gravity fed machines) the fuel cannot get down the pipe(s) to the carbs. Next time you test, run the bike stationary till it cuts out, then pull the pipe off the tap or carb feeder pipe, If fuel flows, you have a carb problem if it doesn`t you may have caused a vacuum. With the pipe still off open the tank lid, if she flows, the prob is definitely a venting one. (you will also probably hear a sucking of air sound as you open the lid) Just a thought, I bugger all idea which way round your tap works though Link to comment Share on other sites More sharing options...
R1evad Posted June 17, 2008 Share Posted June 17, 2008 Having said all that, my money will be on sticky float needles, runs long enough to suck the bowls dry, then the restricted flow starves the motor till it dies. Wait a while for the bowls to refill and it`ll run like a good`un till the cycle is repeated. You should move to somewhere really hilly, then you can power up the hill and fill the float bowls while you coast down the other side and so on. A bit like a "Rolls Can`Ardly" but in reverse! Link to comment Share on other sites More sharing options...
ReBorne Posted June 17, 2008 Author Share Posted June 17, 2008 Cheers guys, a few things for me to have a go at then.... I was going to have a shot tonight but women being what women is I had some of the evening planned for me in my absence ;-) R1evad, funny you should say that - when discussing the problem at work I mentioned that I wasn't sure if it had a pot on the carb like my old mini did, coz if it did it would explain how it was always round about the same distance that it happened.... *sigh* awful thing is, I KNOW she's worth all this hassle lol. oldgit, once again thanks - got your mail, interesting stuff. for some reason BT are being asses again and it's not replying through the mail server. Oh, and I got an insurance quote today and was pleasantly suprised :-) YAY!!!! Link to comment Share on other sites More sharing options...
ReBorne Posted June 17, 2008 Author Share Posted June 17, 2008 Ok, just got in from the garage.... tank is still off, sitting on the workmate..... garage is a mess with parts strewn all over the floor again..... but I'm now pretty confident with the carbs and thinking there's nothing at all wrong in that department. The needles are all sitting nicely, no stickiness. Opened from the top the rubber bits (diaphragms?) are sweet, no problem there and everything looks generally squeaky clean and tickety-boo inside. All the movements are smooth and happy. The tap? Hmm, I think that's a different story and I reckon that's where the gremlins are. Did the whole sucky pipe thing, and only a dribble comes out. Moved the tap round, and sure enough one of the settings allows the petrol to flow freely..... if freely is the right word to explain the meazly dribble that comes out. So, tomorrow I teach myself how to disassemble and rebuilt the tap, fingers crossed I'll get some payback for all this time spent. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 17, 2008 Moderator Share Posted June 17, 2008 Looks promising, thanks for the update. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 17, 2008 Moderator Share Posted June 17, 2008 The tap? Hmm, I think that's a different story and I reckon that's where the gremlins are. Did the whole sucky pipe thing, and only a dribble comes out. Moved the tap round, and sure enough one of the settings allows the petrol to flow freely..... if freely is the right word to explain the meazly dribble that comes out. So, tomorrow I teach myself how to disassemble and rebuilt the tap, fingers crossed I'll get some payback for all this time spent. Sometimes the filter mesh is built into the tap, and if you think youre just getting a dribble, could be that. Link to comment Share on other sites More sharing options...
ReBorne Posted June 18, 2008 Author Share Posted June 18, 2008 Woot! Ok, it's peeing down here so I ain't had her out yet, but...... *fingers crossed* I think I've cracked it!!! Like I said yesterday, the sucky sucky just produced a little dribble.... (stop sniggering in the back!). Taking the front off the tap just shows a little ring and the selector itself... the back is where the goodies were hiding, the diaphragm - which looked in decent nick. Movement was ok, nothing stopping it getting back and forth. The inlet has the filter on a pipe and an inlet - being clever I worked that out to be the main and reserve inlets. Seemed like a small mesh filter in the reserve inlet. Cranked up the compressor and put a couple of blasts backward through the tap and guess what? Nothing special from the main pipe except some petrol, but I found that the filter in the reserve inlet isn't a filter - it was just so clogged with crap it was unreal! Flew nicely though. Re-assembled, threw the suction pipe on and gave a quick suck..... and YAY!!! a veritable torrent of fuel pouring out!!! So, tomorrow I'm hoping the weather is good enough to give her a shot, but I'm quietly confident. Ok, so maybe not so quiet.... but HAPPY!!! BIG BIG thanks for all the help. Some of your ideas have been invaluable. Course, if I'm wrong and it's still not fixed, I'm plain outta ideas. lol...... we'll see..... Link to comment Share on other sites More sharing options...
ReBorne Posted June 19, 2008 Author Share Posted June 19, 2008 Ok, got in from work and almost caught a breath before I was opening he garage up and dragging her out.... And I'm more than happy to say I've jst had her out for a run and she's done me proud :-D Flies on my teeth and everything ;-) So, big thanks to you guys not just for the literal help but also being there for me to bounce ideas off. Now I'm just biding time till month end, payday and (hopefully) MOT without problems! Cheers!! Link to comment Share on other sites More sharing options...
Moderator Airhead Posted June 19, 2008 Moderator Share Posted June 19, 2008 Great news Reborne, well done Link to comment Share on other sites More sharing options...
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