Help on CBR400 carbs

[Paul allan]

I’ve just started my CBR400 for the first in 5 years and there was a lot of petrol coming from the pipe from the carbs im not mechanically minded could someone please explain if this will stop or need repaired.
Many thanks
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P.allan

[Easy-X]

Did you clean out the carbs? 5 years is plenty of time for fuel to go bad.

I think you'd best drain all the fuel from the system, remove the carbs and take a look inside the float bowls.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Bhud]

You need to service the whole bike, including the carbs. Check for split/cracked hoses, stuck floats, float levels, cracked O-rings, blocked jets - everything. Carbs off, and do everything. If you do it properly once, it will save you the rigmarole of taking them all off again and repeating the process.

[Paul allan]

Thanks for the response I didn’t no I was too giddy to see if it started. I just put in fresh fuel new battery and it started but a lot of fuel spilling out from the pipes should I drain the carbs because I don’t want to remove them and then have more work to do or can they just be removed and put back thanks
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P.allan

[Paul allan]

Sorry guys only just seen all the responses thanks but a bit out of my depth maybe a bike mechanic and ££££sss I didn’t want to spend thanks again
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P.allan

[Easy-X]

Normally I wouldn't say this but maybe it is best if you get a mechanic to give it a thorough service. I'd rather you were poor but safe than a rich corpse smeared across the tarmac.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Paul allan]

Bhud do you know roughly a cost for the work you mentioned Easy-x yes totally thanks have you a rough idea of cost for a carb overall
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P.allan

[Bhud]

[Paul allan]

Thanks bhud I’ve been on bikes all my life and a lot of biker mates so I think I’ll be ok with my contacts and not get ripped off 👍
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P.allan

[MattE]

Sounds like a float needs adjusting as it isn't sealing. Could you provide more information on where the fuel leaks from as it would help determine the problem but a float not sealing would be my best guess (the O rings inside the floats can perish within that time if the engine isn't run).
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Current>> BSA Bantam D1 1949 + Suzuki GSX600F 1993 + Kawasaki ZX6R '99
Previous>> Yamaha YBR125 (2010) > Yamaha YBR125ED 2012

[Robby]

To just stop it leaking, giving the float bowl (bottom bit) of each carb a sharp tap with the handle of a screwdriver will probably do the job. The problem is down to a sticky float and/or shit on the needle valve. Tapping the float bowl frees off a sticky float. Fresh petrol moving through a needle valve cleans it.

After 5 years, particularly on a bike like that, it should have a proper going over before back on the road. It's a serious amount of work just to check everything, some reasonable expensive jobs are highly recommend (full brake strip and clean) and some things are going need to be replaced just because of age (probably brake lines). Tyres are probably ancient too.

If all you want to do is get it running and MOTed, then sorting out the fuel leak and giving it a ride will help with a lot of things. Petrol cleans carbs well, particularly when assisted by a bit of heat, motion and vibration from riding the bike.

If you want to ride it more than that, it should have a proper going over. The bits that fail in a really dangerous way (brakes, tyres, chain, suspension) will also fail when they're under the most load and you need them most (braking hard, at speed).

To do all the work that I would do to a bike like that to put it back on the road would cost more than the value of the bike if you're paying a mechanic. Then another £200-500 in parts.

[Bhud]

Good luck getting your carb issues sorted out.

With regard to comments about servicing the whole bike, I think that's something you also need to seriously consider. When otherwise good bikes are left standing they turn into projects. Going by what was needed on my GT550 last year (a good bike which had just been left standing), where I did all the work myself and didn't use a mechanic, the parts outlay for recommissioning well exceeded the value of the bike, and you should be prepared for this.

Example parts budget:

New front and rear tyres: £200-£300
New brake lines: £60-£100
New rear shock: £100-£250
New brake pads: £40-£100
New brake seals and/or pistons: £20-£80
New brake fluid: £5
Forks overhaul (dealing with scoring/rust spots, stiction issues, etc.) requiring new fork oil, seals and bushes: £50-£80
Budget for random seals gone bad (e.g. gear shift) and springing a leak: £30
Bearings (various, depending on need): £30-£60
All new fuel line and vacuum rubber hoses: £10-£20
New chain and sprockets if necessary: £100
Tank rust remover and cure and other treatment as necessary: £30
New battery: £30
Carb repair kit x 4: £40-£50
Budget for carb parts gone bad from disuse (e.g. diaphragms) or damage in servicing: £50-£80
Spark plugs: £20
Oil filter: £5
Air filter: £10
Oil replace: £20-£25

There could be a lot of other stuff needed, besides the items on this list, just on account of having been left standing.