# Help With Carburettor Problem Please!



## scottishcammy (Jul 11, 2003)

Ok chaps, number one, I'm a **** mechanic, in fact, I'm no mechanic at all!!!

For starters, I've just got my new bike (well chuffed). It's a 4 stroke v twin 125.










Now, the bike would start and run fine, but the idle was around 1000rpm and would keep stalling. So, I found the idle screw: however, I broke the idle screw (see, told you I'm a **** mechanic).

Anyway, as the idle cable was broken, I turned (what I think/was told on another forum) were the 2 screws on the carb a very small amount clockwise, around a quarter of a turn.

I've been trying for ages to start it (battery thing sorted, thanks chaps) but it won't start at all now!

I noticed after a while a strong smell of fuel and I noticed a large puddle under the bike (arrrggghhh!!!) which was coming from one of the pipes from the carb.

I've turned the screws back to where I think they were, but still no joy.

I'm desperate to get out on the bike and really annoyed at myself that I've buggered it when it was starting before.









Now I strongly need some advice pleeaassee!



















The last pic is the pipe the fuel came from, the one with all the white crap on the end of it.


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## jasonm (Nov 22, 2003)

A washing up bowl...Does that help?


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## strange_too (Feb 19, 2007)

Sounds like you've flooded it. Leave it a bit, let the fuel vaporise off and you should be good too go.

The only carbs I know about are ones used on Vintage Bentleys and they are there just to dump fuel in the chambers.


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## jasonm (Nov 22, 2003)

Isnt the 'white crap' corrosion/oxidation? That may not be enabling a decent seal?


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## pg tips (May 16, 2003)

carbs can be an enigma, japanese bike carbs are like trying to do a rubik cube blindfold!

can't make out for sure but that looks like the float chamber overflow drain pipe. Sounds like the float valves aren't shutting and it's flooding fuel out through the overflow.

The other screws you've fiddled with are probably the mixture screws? If it's set too rich or too lean it will be a bitch to start.

I'm not being funny but best get it to someone who knows what they are fiddling with.

Where have you got the choke set? What does the manual say about choke setting when cold? Most bikes are critical for the right amount of choke.


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## KEITHT (Dec 2, 2007)

One screw will be the mixture screw, the other the drain for the float bowl.

If you have loosened this that would explain the puddle of fuel.

If you have broken the idle screw, and fiddled with the mixture screw you have little chance of putting it right.

Always, in future, turn the screws inwards first, counting the amount of turns, then at least you know where to go back to, alternatively don't mess with them in the first place and get somebody who knows what they are doing. Huh, great advice after the event i know, just wanted to do the whole told you so thing!

At least its a Honda, so once sorted it will probably be a reliable means of transport, thank your lucky stars ypu don't have one of these!!!


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## scottishcammy (Jul 11, 2003)

pg tips said:


> carbs can be an enigma, japanese bike carbs are like trying to do a rubik cube blindfold!
> 
> can't make out for sure but that looks like the float chamber overflow drain pipe. Sounds like the float valves aren't shutting and it's flooding fuel out through the overflow.
> 
> ...


The manual says for the choke to be out full for starting and slowly put back in.

Could I turn the screws fully clockwise and then turn them back 1 1/2 turns?


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## pg tips (May 16, 2003)

1 1/2 turns used to be a rough rule of thumb but tbh my bike knowledge is at least 20 years behind the times.

When the idle screw broke did it actually move or is it seized? If it didn't move you can rule that one out of the equation.


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## scottishcammy (Jul 11, 2003)

It would only turn (clockwise to increase idle) a tiny bit then spring back. So, like a right arse, I got the big screwdriver out, soaked it in WD40 and gave it big licks (I know, I know







). It turned easily after a bit, but on looking the wire had snapped. The wire is coiled and I appeared to have kind of uncoiled it if that makes any sense!

I'm becoming increasingly pissed off with myself!!!


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## pg tips (May 16, 2003)

big licks!

Are you sure you weren't in the REME?









the coiled wire I assume is the spring that stops the screw vibrating loose.

I think you may have to bite the bullet and get a man in


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## enbee23 (Nov 9, 2007)

KEITHT said:


> One screw will be the mixture screw, the other the drain for the float bowl.
> 
> If you have loosened this that would explain the puddle of fuel.
> 
> ...


Oi!!! I used to have a 650 Sport. It was great, never broke down more than once a month









One problem it didn't have was carbs as it had Weber Marelli EFI which actually did run without any glitches.


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## scottishcammy (Jul 11, 2003)

pg tips said:


> big licks!
> 
> Are you sure you weren't in the REME?
> 
> ...


I've not described the idle cable properly, here's a pic (after it had received one of my 'big licks')







:


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## KEITHT (Dec 2, 2007)

That cable is knackered, its come unwound.

I wound suspect that the choke barrel has seized and as you unscrewed the whole assemble it unwound the cable, looks like you need a new inner cable.

Keith


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## pg tips (May 16, 2003)

coil of wire ???

Keith's right, that looks like one fkd inner cable. The cable from the throttle moves a slide up and down in the carb, on the bottom of the slide is a tapered needle that fits in a hole (called a jet). This is where the fuel comes in. If that slide is stuck full up the jet will be full open hence loads of fuel and flooding!

New cable require mate!


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## KEITHT (Dec 2, 2007)

enbee23 said:


> Oi!!! I used to have a 650 Sport. It was great, never broke down more than once a month
> 
> 
> 
> ...


EFi is quite reliable, its the rest of the electrics that are a problem. Rev counter has mind of its own, temp gauge doesn't work ( all the time) indicators tempremental. Plus the mixture, idle adjustment is a bit hit and miss, i have had to enrich the mixture somewhat to allow for cooler running and the open pipes she is wearing.....great noise, although i suspect plod will not think so!!!

Mines the Kevlar Series version, great handling bike with top notch spec, shame about the overbored 1950's engine, its a bit peaky with a terrible reputation for self destruction.....oh well, despite her faults i still love her.


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## enbee23 (Nov 9, 2007)

KEITHT said:


> enbee23 said:
> 
> 
> > Oi!!! I used to have a 650 Sport. It was great, never broke down more than once a month
> ...


I totally misread your first post, thought you were having a pop at dodgy Italian engineering!

My 650 was a 1995 model, original Kevlar series, chassis number 1122. I had it from 1997 to 2000. Changed the exhaust from original "shoebox" centre section to the later X-over pipes and fitted the appropriate EFI chip. The fuel level sender leaked, the (Ducati sourced) voltage regulator failed, the headlight was absolutely dismal, the speedo used to take an occasional huff and refuse to work, an engine mounting bolt vibrated itself loose and was never seen again, relays failed occasionally and most frustrating of all, the fuses couldn't be trusted to stay put in the fuseblock which was mounted upside down. Gravity and vibration used to rattle them out until I bodged them in with gaffa tape...

I loved that bike. It sounded great and looked wonderful and I never saw another one out on the road. Got rid eventually when an issue came to light regarding recall work on the engine that hadn't been done on my bike. I only discovered this after the 3-X warranted mileage had (just) elapsed so I was going to have to stump up a four figure sum to have my local (rubbish) dealer fit a new head and pistons/cylinders... No thanks.

Well done for persevering with the old beast. Lovely bikes.


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