Help,
I,ve pushed it further than it,s been ridden over the last 3 weeks.
Honda CBR1000F has 3 times in the last 3 weeks flooded when it's been either(1)sat with the choke in on a cold engine at idle (2)choke has been put off when it should run again on a cold engine and (3)having been started on choke allowd to warm up 2 minutes then allowed to idle and blipped to 2000 rpm has died.
Subsequent investigation has proved sparking at all 4 plugs when hitting the starter so it appears that the colis, leads and plugs are fine.
However the fuel system draws fuel thru the fuelcock by vacumn action so apart from a hole in the hose what would cause a vacumn to fail.
Had all 4 carbs balanced last saturday, and it was fine this monday, and when warmed up pulls like the "Flying Scotsman".
Could a vacumn problem manifest itself as a choke problem?
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Is the choke sticking? My last Suzuki's choke cable siezed causing it to run rich and die.
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\"Nothing less than 8 cylinders will do\"
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Agree with v8man, a sticking choke could cause it to run rich. However the fact that work was done to the carbs as recently as a few days ago suggests that you should go back to whoever did the work with the problem. My ZX7R only needs 90 secs of choke even on cold morning.
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My YZF750 has a fuel pump, and a vacuum feed that opens a valve, on mine the membrane is faulty so the valve is always fully open, flooding the bike on idle, maybe a rebuild kit for your fuel tap is needed.
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That's what i am thinking, even though on inspection the tap membrane appeared complete it was certainly showing the fact it has been submersed in fuel for the last 10 years.
If this is playing up it may explain the intermittent problems i,ve been having with my choke, and what i thought was flooding was indeed fuel starvation.
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Doug-r1 has the most likely explanation, although I don't know the Honda that well. A month ago I had exactly the same symptoms and the problem turned out to be a crack in the feed valve membrane. My tech said he never reassembles a carb without replacing all wearable parts because therre is inevitably some sort of problem afterwards, once they have been disturbed.
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Cheddar, my last bike was a ZX7R and it needed a lot more than 90secs of choke. What's your secret? All my Kwaks have exibited the same problem when starting from cold - namely, an odd number of cylinders firing until warm.Even my ZX12R is a bag of nails when cold. Character, that's what!
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\"Nothing less than 8 cylinders will do\"
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I sold my previous bike( a paragon of reliability) to buy this CBR1000F. What's worse is that i live at the top of a hill and pushing 235 Kg of bike +fuel+kit @0650 is NOT my idea of fun.
I am temped to take the fuel line off the tap and fill it with fuel just to see if it starts.
Where can you buy fuel tap sets i.e seals and springs apart from my local dealer?
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Hi. I have a very old 1000FH, which may be a similar fuel set up to yours(or of course totally different). Not used enough, so can be troublesome to start after being idle for several weeks, but once it does fire runs on choke, getting faster and faster if I leave the choke fully on. Shutting the choke slightly, so it comes off the fast idle, can cause it to stall unless it is hot.
Have you had the Honda long? Has it been the same since you had it, or is this a recent problem.
The manual for mine shows fuel fed by an electric pump, with 2 filters (a coarse one above the fuel tap) and with the fuel tap only allowing fuel through if the line is under vacuum from the pump.
Having a faulty vacuum diaphragm should not make any difference, I would have thought, once the engine was running. All it would do would allow fuel through to the carbs when the thing was parked with the engine off? Make cause leakage of fuel into the inlet if a carb valve is faulty, but that is not your problem. My money would be on the choke setup, if the mixture is really too rich. Is the fast idle coming on?
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My money would be on the choke setup, if the mixture is really too rich. Is the fast idle coming on?
It's a 1995 FS, i bought it in October of last year, sat in my garage over winter being brought back up tip top standard.So has not been used that much, might just be that it needs choke untill the engine's warm.However that doesn't explain why it now doesn't start.
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(statement of bleedin' obvious coming up): get a good Honda tech and pull the whole fuel system, replacing all wearable parts. If you got sparks and you've got gas it must start and run according to the immutable laws of internal combustion and barring catastrophic mechanical failure.
What colour are the plugs? If you stick your nose under there do you smell gas? (sorry..petrol :+( )
My money would still be on worn parts being put back as opposed to being replaced. Or simply overlooked.
I'll put your post to John Hoffmann one our local experts who does a lot of work on big Jap bikes when I see him this week and see if he has any ideas -- I'm thinking he or one of his mechanices may have encountered similar before.
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The plugs are in effect brand new i only fitted them the beginning of March. NGK's as specified by the owners manual.It's a bit difficult for me to ascertain if i,m getting fuel in the cylinders as i,ve got no sense of smell (Nose op 2 years ago!).
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I was thinking more of slight petrol vapour leaks around the petcock and the carbs generating a smell which might indicate a fault. This was got me alerted to my problem when the bike started to die when the enrichener was pushed in or when the bike refused to idle when hot. The vacuum pump wasn't working, simple as that. With the enrichener knob full out, no problem. With it in, either too much or too little fuel (turned out to be too much, as the state of the plugs bore out when we pulled them) was causing the bike to die.
The membrane was the problem in my case. Old and tired.
Starting was also laborious, whereas normally she started on the very first crank, even after a month of non-use.
I'll lay your comments on my guys anyway, might be something, maybe not, but we'll doubtless all learn something, as one does from these things.
I won't be your plugs, it has to be the fuel system somewhere.
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Well, i,ve just got it back, and apparantly there is nothing wrong with it.Apparantly the idea is to start with choke when cold and as soon as it's going give it a couple of blips and it'll run at an idle. The garage had it 3 days and it started on their first try (!!), kept it for another 2 days and it's started fine each time.
Bit wary of using it but i'll try what i,ve been told and seeif it makes a difference. Allegedly CBR 1000's can be a bit difficult to get used to how to start.
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Sounds like it's OK then. Unless it's one of those problems where the symptoms only manifest themselves when a mechanic isn't looking at it!
I mentioned your "problem" to my guy last night. He is well familiar with CBR 1000's and doesn't know of any "built-in" starting methods such as you mention. But then we live in high ambient temperatures where the choke is seldom necessary.
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