leaks petrol

if I leave my t80 in the garage for a week there is a strong smell of petrol plus some times the tank is empty ive changed thee carb but no difference, do you think its the carb or thetap or what

I was wondering could it be anything to do with ethanol in the modern petrol,, have any one else had any problems

barker wrote:if I leave my t80 in the garage for a week  there is a strong smell of petrol  plus some times the tank is empty ive changed thee carb but no difference, do you think its the carb or thetap or what

Its the tap, is it in the prime position? as this lets the petrol flow to carb when engine not running. If not its the diaphragm in the tap split, again letting fuel flow. You cannot get new diaphragm kit so will need a new tap.

A sensible solution would be to put a clean bit of cardboard under the bike, if it's under cover and not outside) to see where the petrol leak is coming from.
If it's the carb it's probably coming from the overflow so check the float level, if it's the tap then a replacement is in order, could also be a dozed fuel line coming from the tank.

alibx11 wrote:A sensible solution would be to put a clean bit of cardboard under the bike, if it's under cover and not outside) to see where the petrol leak is coming from.
If it's the carb it's probably coming from the overflow so check the float level, if it's the tap then a replacement is in order, could also be a dozed fuel line coming from the tank.

If its the diaphragm in the tap it will just let petrol flow to carb, in an ideal situation the carb should not flood, but it only needs the float needle to not fully seat & over a period the carb will flood via the overflow tube. If the tap is shutting off correctly this wont happen. My money is still on the tap.

I have some spare taps give it a go next week

so as I ve got it right what is the prime position up or down the lever bit I mean

barker wrote:so as I ve got it right what is the prime position up or down the lever bit I mean

Normal running Straight down. Prime Horizontal. You asked the same question before in 2012 https://yamahatownmatet80.forumotion.co.uk/t145-petrol-tap?highlight=Petrol+tap
When tap is in normal (straight down position) no petrol should flow until engine is started, the vaccum from induction opens the tap.

Is that a left hand drive T80 you have pic'd?    

The prime position is straight across, having the tap vertical is the vacuum operated function.

LOL... "is that a lhd townmate?", nice spot John.

just wanted to be sure,2012 you have a good memory , once ive mended the fence that storm Katie destroyed I will get on with the t80

barker wrote:2012 you have a good memory

not really, just searched for petrol tap

finally got round to looking at the t80 took the pipe off at the tap end that goes to the carb , and as some of you said tap leaked, so changed it now no petrol leaks

bloody thing wont start now so changed the plug , good spark but no petrol reaching the piston so changed the carb , what a pig of a job getting the air filter pipe back on to the carb, tried heating it in water no joy in the end I split the carb end ,put it on carb wrapped gaffer tape around it then fitted a jubilee clip, gave up to night on it as the light was fading, continue tomorrow

barker wrote:bloody thing wont start now so changed the plug , good spark  but no petrol reaching the piston so changed the carb , what a pig of a job getting the air filter pipe back on to the carb, tried heating it in water no joy in the end I split the carb end ,put it on carb wrapped gaffer tape around it then fitted a jubilee clip, gave up to night on it as the light was fading, continue tomorrow  

As it was going ok prior to changing the tap, then it must be that the replacement tap is faulty, diaphragm in tap punctured maybe so that the vacuum is not created to open the tap. Did you try it in the prime position to see if petrol flowed then? Trouble is that the taps deteriorate by standing & diaphragms harden & split, the only real solution is to buy a new tap but they are expensive at £27.35 from A J Sutton https://www.yamahamotorcyclespares.co.uk/product/yamaha/35T245000000/fuel%20cock%20assembly%20t80%20townmate,%20t50%201986?uid=0
Always pays to sort these problems starting from the cause of the original problem, a neighbor of mine spent over £100 on having the voltage control box converted to electronics after his charging light failed to go out on his MG Midget. In the end it was a sticking brush in the dynamo which cost nothing to fix, just a bit of WD40.  He should have checked the dynamo first.

my new tap has arrived, if I connect thetap up to the tank and turn it to prime petrol will run through , if I turn it to vacuum no petrol will run run through is tis right,

had a lot of bother with my delivery from suttons they had no record of my order even tho I was charged for it turns out it was pay pals fault