Xt 125r petrol leak

[davidjlambert]

Hi

Following on from my previous question, the petrol smell turned overnight into rather a substantial leak fortunately I'd put a tray underneath and caught a lot of neat petrol. Good thing it wasn't parked up near an ignition source!

My guess is that the float has jammed open but why would the petrol still flow when the engine has stopped.

The vacuum tap seems to operate properly. With the tank off there is no flow from the tap.

Any ideas gratefully received

Thanks

Dave

[Airhead]

Hi

Following on from my previous question, the petrol smell turned overnight into rather a substantial leak fortunately I'd put a tray underneath and caught a lot of neat petrol. Good thing it wasn't parked up near an ignition source!

My guess is that the float has jammed open but why would the petrol still flow when the engine has stopped.

The vacuum tap seems to operate properly. With the tank off there is no flow from the tap.

Any ideas gratefully received

Thanks

Dave

Yep youre right Dave, if the vacuum tap is working this cannot happen!

so where is the leak coming from then?

[davidjlambert]

Thanks Airhead

I wonder if the vacuum line could be partially blocked and holds the tap on after the engine has stopped.

It certainly doesn't add up.

If the worst comes to the worst then I'll fit a small tap in the petrol line, not what I want to do but I need confidence that it won't happen again.

It could have led to the garage burning down.

My main thought is a float problem which somehow is leading to the bowl siphoning via the overflow. Doesn't make sense though.

Hope to play with it tomorrow and see where we go

Thanks

Dave

ps I've already partially stripped the bike so cannot determine where the leak was from. My guess is the overflow pipe. The tank certainly has no leaks.

[Airhead]

you could try sucking on the vacuum line a few times to test the action of the flow / no flow

[davidjlambert]

I'll certainly try that although I have to say I feel much more comfortable with the old style tap with on/off lever. Doesn't seem to be a way to convert easily especially as the tap is so tucked away.

Incidentally where can you buy spares to the xt. I've browsed the Internet with very little success. If I need a new float needle or gaskets do you know who'd have them?

Cheers

Dave

[Airhead]

You'll most likely have to go to a yamaha dealer dave, If thats not easy for you try phoning one

Fowlers of Bristol if you cant find help locally, you'll need your model code I guess, is there a sticker somewhere on the frame...perhaps beneath the seat?...sorry i'm not familiar with the model but others on here have them

[Grouch]

Dave,

You can buy parts from.........

www.wemoto.co.uk

www.ajsutton.co.uk

and my favourite place is eBay.

I think the problem your experiencing is very rare. Hopefully it

will be something and nothing and won't break the bank to repair.

[davidjlambert]

Thanks chaps

Hopefully tomorrow may be revealing.

The spares contacts proved interesting, a mere float needle comes in at £40 and starter motor £346! Hope I don't need to buy too many spares.

I'd hoped others on this forum may have had the same problem but seemingly not.

Cheers

Dave

[Airhead]

It is really unlikely that you will need either a float or a needle, usually the float needle valve may have just jammed

sometimes a gentle tap on the carb with the wooden stock of a hammer will free it, but as we have said before the vacuum tap should be stopping the leak anyhow

Starter motor?

[davidjlambert]

Carb off, stripped. Rebuilt, float height as per Haynes manual 18.9mm.

Refitted on bike, fuel pours out of overflow although checking fuel height from drain indicated it was below the overflow pipe!

Float bowl off numerous times to bend the float tab, still no good. Float needle looks fine.

Got fed up and left it for tomorrow.

It seems to me that I've got to adjust the float so a minimum level is achieved in float bowl which will mean the measurements will be way different to those specified.

Vacuum tap works as it should.

Any ideas and answers gratefully received.

Cheers

Dave

[dt502001]

Dave try fitting the carb with the bowl off and hold the float up by hand.......... and see if it actualy stop the flow of gas in prime position...... the needle seat in the carb could be crap. And the excess fule in the line is causing the over flow

Also does the tank have rust? And have you tryed to float the "floats in gas to see if they actualy float?

[Grouch]

Dave try fitting the carb with the bowl off and hold the float up by hand.......... and see if it actualy stop the flow of gas in prime position...... the needle seat in the carb could be crap. And the excess fule in the line is causing the over flow

Also does the tank have rust? And have you tryed to float the "floats in gas to see if they actualy float?

The tanks are plastic on XT 125's

[davidjlambert]

Thanks chaps

I think I've cracked it this morning. I just kept adjusting the float tab until the bowl stopped overflowing. Didn't think to do the dodge of testing the system with the float bowl off. Good idea for next time.

As Grouch says, the tanks are plastic and the carb interior was very clean apart from some very fine debris in the bottom of the float bowl.

Next job, change the oil. Be interesting to see if there is fuel contamination. Also going to drop the forks by about 30mm.

The bike is new to me and not been used yet. Following on from the comments about the speedo, I intend to use silicon to seal it as it seems rain is the usual culprit?

Anything else I should focus on before giving it a thrashing?

Thanks again

Dave

[welshwan]

my carb keep fucking flooding too!!!! had the bike striped down like 4 times man, works just fine once put back together but if left more then a few days without giving it a fairly good run it will flood and need to be striped and drained again ...put back together and all is good. What a pain! so u sorted it now then dave?

[davidjlambert]

Hi welshwan

Yep I sorted it by bending the float lever tab and I had to do it way more than 4 times before it cured the problem. It's way different to the measurements in the Haynes manual but it runs fine.

I also don't trust the tap so I fitted another in line tap down near the carb. I think what happens is the bike stops but for a short while the petrol feed doesn't immediately stop and there is a fuel line full of petrol.

Then the float needle tip must be just letting by and the petrol in the pipe fills the bowl with nowhere to go but the overflow pipe.

Now I turn the in line tap off before stopping the engine so there is virtually no petrol in the pipe so no overflowing.

Not ideal but it seems to have cured the problem.

It's a bloody dangerous problem cos if it happened in a garage with an ignition source such as a fridge, dehumidifier or even a light switch then there could be an explosion and fire. I was surprised by the amount of free petrol that came out of the overflow pipe.

The oil was fuel free when I changed it so I assume the diaphragm in the tap is ok and neat fuel isn't flowing down the vacuum pipe straight into the inlet manifold.

Hope you sort your problem ok.

Cheers

Dave

[welshwan]

just been going through some old threads thanks for all the advice there mate!

i will have to get a tap ordered as i have been having to disconnect the fuel line and letting it run dry so to speak and then its usually fine for the next day .

that reminds me its probably about time i changed my oil too!