Date: 29-03-24  Time: 02:37 am

Author Topic: Carburetor quandary!  (Read 1868 times)

Gabrael72

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Carburetor quandary!
« on: 16 June 2019, 09:58:33 pm »
Hi foccers, I'm in need of your combined wisdom.
Recently experienced problems with number 1 cylinder not firing, got fuel, got spark, drained bowls and found crap in the fuel. Removed carbs, cleaned all diaphragms (no holes or kinks) cleaned bowls, cleaned all jets, reassembled and ran, bike fired on all 4 (hooray,) started next morning and back to 3 cylinders getting hot, this time number 1 was fine but number 4 not hot now, have I missed something?
I know I need to get new bowl rubbers as I can see one of the bowls weeping a little (any advice on reliable seals?)
It's got me baffled?

darrsi

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Re: Carburetor quandary!
« Reply #1 on: 17 June 2019, 05:47:48 am »
How old are the plugs, and which ones are you using?
Reason being, i bought a set of NGK's about a couple of years ago and they turned out to be fakes.
First one lasted about a month, then the 2nd one packed up about a week or two later, forcing me into buying another new set.
I'd kept my old plugs so was replacing the dud ones with them to keep the bike running, but the cold downpipe was the first giveaway sign, apart from rough engine running.
More people are born because of alcohol than will ever die from it.

Riggerlee88

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Re: Carburetor quandary!
« Reply #2 on: 17 June 2019, 10:28:04 am »
I have been rebuilding mine over the last week I purchased new rubber gaskets for the bowls in the Link off Yambits hopefully this helps


https://yambits.co.uk/fzs600-fazer-float-valve-carb-kit-p-88849.html?osCsid=kf1pvh8i72cf42jp9gnsiheu71


Gabrael72

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Re: Carburetor quandary!
« Reply #3 on: 17 June 2019, 10:41:11 am »
Thank you very much, will take s look at the link, here's hoping yours all goes to plan! 👍

Riggerlee88

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Re: Carburetor quandary!
« Reply #4 on: 17 June 2019, 04:02:34 pm »
you're welcome good luck

His Dudeness

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Re: Carburetor quandary!
« Reply #5 on: 17 June 2019, 08:46:24 pm »
I'd take out spark plug on 3 and check that the cylinder isn't flooded. Crank the engine a few times and look for fuel spraying out of the cylinder. If it's not flooded you could check for spark while you have the plug out. Be careful not to light yourself on fire :lol If it is flooded the float valve in carb 3 is probably stuck open. If it's flooded check the oil level. The petrol washed down the cylinders and contaminates the oil. If it's not flooded put the plug back in. Turn the choke on and start the engine. Let it run for a few minutes with the choke on. Does the exhaust on cylinder 3 start to get hot with the choke on? If it does then that would suggest the pilot circuit is blocked in carb 3 and you will have to clean it. You said there was dirt in the fuel when you took the bowls off did you give the tank a clean? If not I'd give it a clean with some fresh fuel. Was there any water in the bowls? If so I'd check the drain on the tank. If the drain is blocked rain water will collect around the filler neck and get into the tank , then it settles in the tank and the carb bowls and makes starting difficult. To get to the drain you open the filler cap and take the allen bolts out and give the drain a poke and a spray of wd40 to clear it. The main thing is check if it's flooded, if it's not run it with choke and check if cylinder 3 gets hot with choke. If it does the pilot circuit on 3 is probably blocked.

Gabrael72

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Re: Carburetor quandary!
« Reply #6 on: 19 June 2019, 09:46:34 pm »
Thanks for the advice, took the carbs out again & gave them all another thoroughly good clean, this time I changed all the float pins & seats alongside new bowl rubbers, will put back in the bike Friday and let you know how it has gone?
Hopefully i'll have good news 😉

Gabrael72

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Re: Carburetor quandary!
« Reply #7 on: 22 June 2019, 04:07:15 pm »
SUCCESS!!!
Carbs went back in this morning and after backfiring loudly at first it ticked over and ran like a dream, guess I won't have to burn it after all 🤣
Took it straight down for MOT (& asked them to balance the carbs as I thought they may need it?) And it passed with no advisories and didn't need the carbs balanced as they were spot on!

Thanks to everyone that offered advice, I'm one happy foccer again. 👏👏👏

Gabrael72

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Re: Carburetor quandary!
« Reply #8 on: 23 June 2019, 11:15:20 am »
The Happy foccer is no more!!! 😩

After taking the bike out for a blast last night (had a ball) did around a 50 mile watering hole trip (only half a pint all told 👍) when my friend said he could smell fuel, looked around the bike, checked carb bowls as put new gasket rubbers in, checked fuel lines, pump, overflow lines too, completely dry?
Rode home and parked up placing it on the sidestand, checked on the bike half hour later & noticed a small patch of yellowy brown liquid by the foot of the stand, sniffed it and it smelled like that breather pipe smell from the sump (hope you know what I mean?)
Followed it to the point of exit and it's coming from the bottom left front of the airbox!
From all I've read from various posts on here it sounds to me as if fuel has gotten both into the air filter & into the engine with the oil?  I have recently changed the float seats (& O-rings) plus the float needles.
I didn't set the float height, just straight swapped them over.
What are your thoughts, do my symptoms point towards the float height?




His Dudeness

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Re: Carburetor quandary!
« Reply #9 on: 23 June 2019, 12:01:21 pm »
That pipe on the bottom left of the air box is the breather for the engine case. Pressure in the engine case is vented out through the pipe into the air box. Over time oil, water vapour and combustion gases coming out of the case mix together and can cause a build up of emulsified oil that blocks the pipe. The mayo looking goo can be from normal build up and it just needs a clean out or it can also happen if the oil level is too high so the pressure in the engine case pushes an excessive amount of oil into the air box. You should take the breather pipe off and give it a clean and look in the bottom of the air box for goo and give it a clean and check if your oil level is high. A bit of mayo goo in the air box is normal. A lot of oil isn't and would suggest the oil is over filled. A blocked breather pipe by itself shouldn't cause the bike to run rich. Do you think the bike is running rich or is the only problem that there is goo coming from the air box?

Gabrael72

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Re: Carburetor quandary!
« Reply #10 on: 23 June 2019, 12:45:43 pm »
Thanks for such a rapid response His Dudeness 👍The main issue is the very present smell of petrol, you can smell it all around the bike, since cleaning the carbs (twice now) & putting in the new float seal kit comprising of bowl gasket, main jet O-ring, float seat with O-ring & float needle/pin the bike seems to run fine but just smells of fuel, I've checked all areas where fuel could be leaking/evaporating and everywhere seems ok, it was only after taking it for its first ride out after the work that the smell was noticed & that pool (about 15ml) of "substance" was seen by my sidestand, it's the first time I've seen that since having the bike this last three years, I just kind of put the two together?
I'll check the oil in the engine & the breather pipe you mentioned later today & see what's what, it's just driving me mad, I want to be out riding and not throwing time and money at this to no avail 😩

His Dudeness

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Re: Carburetor quandary!
« Reply #11 on: 23 June 2019, 01:01:54 pm »
You'll get there eventually, you just have to tick off one problem at a time. I'd check the oil level, check if the plugs are fouled, check the air box for fuel or oil or emulsifed oil, clean out the breather pipe. It could be flooding into the airbox and coming out the breather or the breather could just be blocked, you will have to get in there and look for evidence of what's happening. Is the engine running normally?

Gabrael72

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Re: Carburetor quandary!
« Reply #12 on: 23 June 2019, 01:04:13 pm »
Yeah seems to be, I'll take a quick vid & put it on YouTube.

So here's the link...,
https://youtu.be/kJnLWvEXM-s
« Last Edit: 23 June 2019, 01:25:13 pm by Gabrael72 »

His Dudeness

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Re: Carburetor quandary!
« Reply #13 on: 23 June 2019, 01:44:42 pm »
Sounds like it's running normally to me. The idle is a bit low. It should be around 1150 to 1250rpm when hot. There's is definitely a bit of wetness under the carb near the air box. It's hard to tell where exactly it's coming from. It looks higher than the breather pipe and it's not the usual emulsified oil. Is that rust on the ground from the leak? It looks a bit like rusty coolant water. Is the wet area coolant?

Gabrael72

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Re: Carburetor quandary!
« Reply #14 on: 23 June 2019, 01:54:36 pm »
Yeah I agree the tick over was a little low, but that was a cold start with no choke, picks up a bit after a few mins.
The goo from the airbox was kind of a caramel colour & thicker than just coolant, that stain on the ground has dried out from what dripped last night.

His Dudeness

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Re: Carburetor quandary!
« Reply #15 on: 23 June 2019, 02:24:02 pm »
Pull the breather pipe out of the air box and check it. That's probably the best place to start

Gabrael72

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Re: Carburetor quandary!
« Reply #16 on: 23 June 2019, 02:39:29 pm »
Will do, watch this space!