Fazer Owners Club - Unofficial
Bikes, Hints'n'Tips => FZS600 Fazer => Topic started by: rsvphil on 13 November 2015, 02:08:11 pm
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Hey everyone got a problem with my brothers bike. He asked me to do some work, fork seals, chain sprockets etc but then decided to tell me it wasn't running properly. It would only run on the choke and wouldn't tick over, as soon as you touched the throttle it would cut out. I drained the carbs and removed them and gave them a quick clean made sure the jets were all clear. Refitted them and couldn't get it running. After leaving it overnight it fired straight up and revved really high for 2 seconds then wouldn't fire again. If you leave it for a period of time it will start or attempt to start for a couple of seconds then nothing. It does turn over and spark fine it's just not getting fuel. The float chambers are full of fuel. Any help much appreciated .
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Is it definitely not getting petrol, or could it be an air leak with too much air?
Working with choked air could point to that.
Try starting it then whip a plug out and see if it's wet with petrol, or dry, which will determine whether petrol is getting through or not.
If it's wet then maybe check the carb rubbers for cracks, and make sure they're refitted and seated properly.
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It ran on the choke before the carbs came out now the choke doesn't have any effect. If you leave it for a period of time it will fire straight away and rev to about 6000rpm for two seconds then dies then won't fire again unless you leave it for half hour. Whilst it does run twist the throttle has no effect. Checked over everything again and again and can't see anything out of place or damaged.
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Check the air and fuel filters
Rule out the obvious first
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Fuel filter replaced and air filter checked.
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Is the tank breather hole clear, that could cause fuel starvation?
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Yep all clear. But surely that wouldn't explain why it will run for 2 seconds when it's been left for half hour then not run at all? It's baffling me. I think the carbs are gonna have to come back out
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Yep all clear. But surely that wouldn't explain why it will run for 2 seconds when it's been left for half hour then not run at all? It's baffling me. I think the carbs are gonna have to come back out
If that's the case then there's a restriction somewhere and the carbs aren't filling quick enough. Try hooking up another fuel supply straight to the carbs and see if it runs
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Is it definitely not getting petrol, or could it be an air leak with too much air?
Working with choked air could point to that.
Try starting it then whip a plug out and see if it's wet with petrol, or dry, which will determine whether petrol is getting through or not.
If it's wet then maybe check the carb rubbers for cracks, and make sure they're refitted and seated properly.
It's also worth looking at the position and condition of the fuel switch under the tank and the fuel pump. It the floats have fuel I'd say it's a carb problem. Have you checked to see if your getting fuel in the cylinders?
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So far I've checked that there's fuel going through the filter into the pump. The pump is working as it should. And the float chambers are full I just really don't understand it.
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Right had the carbs out again and took the top covers off and removed the diaphragms and needles then removed the float chamber bowls and made sure the jets were all clear. Checked over everything I could see and rebuilt them and fitted them back on the bike. Managed to get it running and without the choke so was mightily relieved. However later on went back out started for a second then died and won't fire. So back to square one.
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What did you set the pilot screws to?
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Everything is set as it should be according to manual. As it was before I fettled with it.
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Is it a foxeye or boxeye?
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you didnt get the main jets mixed up with the blanked off jets did you??
they are the same size and shape as the mains.
although it should still run on the choke (enrichment circuit)
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try leaving the fuel cap open. This will confirm if you have a breather problem.
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If the carbs are full, fuel starvation sounds unlikely. Have you followed up on Darrsi's suggestion and taken a look at the plugs?
Flooding can be due to dirt, damaged needle valve tips or seats, failure of the o-ring seal around the brass valve body, mis-adjustment of the float arm or leaky floats.
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Out of curiosity did you put the fuel pipe from the tank to the fuel filter under or over the frame rail?
It is supposed to go under the rail as going over the rail could cause it to be squashed by the tank limiting the fuel flow.
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Hi all sorry for the delay had some unexpected health issues since my last post. Fingers crossed I can get this bloody bike going now. Just been out this evening and turned the bike over. The fuel pump primed straight away But made no attempt to fire. Checked all spark plugs and getting good spark. At a complete loss.
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Did you try it with the choke on or off?
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Tried with choke without choke. Nothing won't fire at all.
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Switch off your fuel tap and remove one of the wires from the back of the fuel pump. This will prevent any more fuel being fed to the float bowls (If its a flooding issue) Then try starting it, if flooding is the issue then hopefully it should run on until it runs out of fuel.
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Tried turning the fuel tap off and still nothing.
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I suspect one (or more) of your carb's slides is stuck open. I had a very similar sounding experience on my RD350LC about 20 years ago.
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Is there a cure for the carb slides sticking open? How did you fix your issue?
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It may be that one of the rubber diaphragms is being / has been pinched upon previous reassembly. Look for any signs of creasing or indentation and make sure the little o-ring is present and in place. Unfortunately as soon as you reassemble the carb tops, it's out of sight, so you can't see if it's in the correct position or becoming twisted as you screw the carb top screws down.
Sometimes they can be straightened out, but if they're old or gone a bit brittle then replacement is the best solution.
Hmm... Wemoto are charging £44 for each single diaphragm:
http://www.wemoto.com/bikes/yamaha/fzs_600_fazer/98-99/picture/carburettor_diaphragm/ (http://www.wemoto.com/bikes/yamaha/fzs_600_fazer/98-99/picture/carburettor_diaphragm/)
Another possibility (which I experienced on my 350LC) is that the carb diaphragm has been put in the wrong way, and by that I mean which way the lower part is facing. It may need to be turned around 180 degrees. On the LC it was the carb body itself but different carb design, same principle.
No idea how mechanically minded or patient you are, so you may wish to just get a second set of carbs off ebay, flush them out and try them instead. Indeed, it may well prove a cheaper solution....
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I always check the diaphragm by sucking on the port on the rear of each carb. You can see if they are all seated and when you suck on the port you should hear the slide lift. Check each one several times making sure it seats correctly when it returns
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Did you check all float heights. Clear plastic pipe on the drain hole and up the side, ignition on for pump to prime and fill the floats.
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I removed the carbs again and checked everything over snd all seemed good. Reassembled and got the bike running a dusted the the idle and was satisfied I'd cured the problem. However after I came back to the bike a couple of hours later it wouldn't fire and hsnt fired once since.
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Sounds like a lack of fuel, is the fuel pump actually pumping, not just making noise? Did you turn the tap on?
If the tap is on fill the tank about half way, prop it up to and bypass the pump (not the filter) to rule it out as an issue.
With the tank half full and propped there will be enough pressure to fill the carbs and run the engine
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Pump seems to be working fine and the carbs seem to have fuel in the float bowls.
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Mine was doing something similar. It would be fine in the morning when starting and would run fine all the way to work (50 miles on the motorway). But go to start it in the evening and it would run for 2 seconds then cut out. It would then take up to half an hour to get it restarted. If you got it to catch pumping the throttle seemed to be the only way to keep it running,
It's just been into the shop for valve clearances and new carb rubbers (cos the old ones were horrible). So far it seems to start much better although I haven't tried it on a run to work yet. The valve clearances were a bit tight too (25k miles). My money's on the carb rubbers for the starting issues. Mind you I had a diesel van which would be a bugger to start but would run fine once started. That was closed up valve clearances too.
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Little update guys. Stripped the carbs out again and reset all the pilot screws. Reassembled and bike fired straight up. Wasn't running properly hunting quite a lot with a delay on the throttle. Basically slow to respond to input of the throttle also seemed to stick a bit before the revs dropped. After letting it run for a good ten minutes switched it off and left it for 20 mins. Came back out and it started up straight away. Left for 2 hours wouldn't start and now back to square one doesn't fire at all.
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Little update guys. Stripped the carbs out again and reset all the pilot screws. Reassembled and bike fired straight up. Wasn't running properly hunting quite a lot with a delay on the throttle. Basically slow to respond to input of the throttle also seemed to stick a bit before the revs dropped. After letting it run for a good ten minutes switched it off and left it for 20 mins. Came back out and it started up straight away. Left for 2 hours wouldn't start and now back to square one doesn't fire at all.
As you're clutching at straws now, try the bike on the centre stand with the side stand up.
My bike has just developed an annoying problem with the side stand switch, it will start one minute and not the next whilst on the side stand, but ping to life no problem and run fine with the stand up.
Still waiting for my replacement switch to arrive at the moment, but as i know the cause it's not such a problem any more and i can easily get around it.
Symptoms were not starting at all until battery was virtually flat, got jump lead started and got it running then it cut straight out with the side stand down in neutral a few minutes later, then refused to start again, until i tried it on the centre stand alone and it became happy again.
Degreased the general area as best as i could at night time around the switch then slapped WD40 everywhere to make sure the cut out piston thingy worked freely in and out, which it did.
Then days later it would consider starting, with the odd backfire, but as soon as i got the sidestand up there was no problem at all, and when i got to work and put the stand down with the bike in neutral it now carries on running fine?
Never know, it may be the same problem, it's not something i've ever encountered on any bike i've had before so it was a new one for me.
I knew it wasn't the carbs because issues with them normally involve a splutter or fart before pegging out, whereas this problem cut the engine instantly dead when it was running.
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Definitely not Sidestand switch the bike is on a table. The bike only starts snd runs when I strip and rebuild the carbs. But once left for a while she won't fire again until carbs are removed rebuilt and refitted.
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It couldn't be the floats or the float valve sticking could it?
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A friend of mine rang me with an issue on a BMW R1150GS he was working on, it was very similar to your problem, might start and if it did start it would not rev, then when it would run it would be fine for a few miles then stop and not restart. It had a good spark so we brought it back to the garage and it started. :groan
I spent a day with him and we checked the injectors and set up throttle bodies. It started and ran fine, we then balanced the throttle bodies and was running as smooth as a button. It then misfired and stopped, would not restart, this time it had an intermittent spark.
We took the pickups off his own bike and fitted them. We had tested the pickups at the start and ruled them out because they tested fine
With the different pickups in the bike started and ran like a dream, he got a new set of pickups, replaced them and bike has been d
running perfectly since.
Long story, but might be no harm in checking the connection on the pickup and the condition of the stator and ensure the pick is bolted on to the stator cover properly
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Did you ever resolve the fault? I’m reliving the same issue after removing the carbs and now I have a lumpy sounding engine when it does run and it cuts out. Now looking at getting the carbs cleaned using ultrasonic. Any thoughts?