Basically you should check your flow rate by taking your carb banjo off and use a container and have the pipe set at the same height that it joins on to the carb.
You don't run it through your needle valve assembly on the carb as this will restrict it as its only a 3.5mm hole versus a 6-8mm pipe. Also check flow rate at full tank, half tank and quarter tank as it will make a difference, for example vespas flow rate is a lot, lot worse at quarter tank as the petrol is almost as low as the petrol pipe joining the carb.......remember we are talking gravity feeds on scoots.
This way you should get at least a pint a minute for a kitted scoot. If you are not getting that... check your fuel pipe run and tap filter in tank. If you are getting that you are fine. The next step is then to check operation of needle valve assembly. pull the float pin out and check for wear on the pin on its pivot points as wear can result in the floats sticking and causing fuel starvation.
P.s. Also check fuel pipe doesn't kink when you sit on the scoot if you see what I mean.
Also make sure it is a good quality fast flow tap (there are some shoddy ones out there) and check tap washer is in good nick. If its letting air in it will cause fuel starvation symptoms as well
Fuel starvation(float needle+valve)?
no you should check it through the float valve!
Really you can check it either way but it is the resulting values that matter. The "a pint a minute" refers to fuel collected at the end of the fuel line and will be adequate if you have a kitted motor. If your going for tuned TS1's, RB's, Racers etc the best advice is to ask your tuner I guess and under what circumstances to test...ie bore of fuel line, taken after valve or before etc.eden wrote:no you should check it through the float valve!
I asked my tuner and he said that it should be from the float needle valve because if the needle valve isnt allowing enough flow through it you could have ten gallons a second coming out of the end of the fuel pipe but the engine will still suffer fuel starvation due to the needle valve restricting the flow.
pretty obvious really.
pretty obvious really.
You are checking tap flow mainly here. Having the correct size needle valve is a different issue. You are limited on needle valve size anyway....they go from 150-400 on dellortos and the size of the inlet hole from banjo to needle valve hole is about 4mm (sometimes slightly smaller) so you are limited there as well and again yes I agree if your tuner said you should get, I don't know, 3/4 of a pint with a 300 valve fitted then go with that but if you want to rule out tap flow starvation you will confuse the issue by testing at the valve as you are limited to the size of the valve.
As long as that 350 valve he has got in is clean it ain't gonna be the problem of fuel starvation as when you test it your going to have it fully open anyway so this will not test if the float pin is causing the floats to stick anyway which would be the only cause of starvation on the float mechanism (you look at the pin by eye to see if its worn). So therefore to accurately test the flow rate of the tap you do it at the banjo, at the same height, with the same bends as when it is bolted to the carb. Only then will you get an accurate reading of tap flow.
Fitting the biggest valve you can get can cause issues the other way as well as you then causing slight interference with float heights as a bigger one will let slightly more fuel through before it closes off otherwise we would all be running 400 float valves and the only off the shelf kit that is recommended to run this that I know of is the super Monza.
Do you not see what I am saying?
As long as that 350 valve he has got in is clean it ain't gonna be the problem of fuel starvation as when you test it your going to have it fully open anyway so this will not test if the float pin is causing the floats to stick anyway which would be the only cause of starvation on the float mechanism (you look at the pin by eye to see if its worn). So therefore to accurately test the flow rate of the tap you do it at the banjo, at the same height, with the same bends as when it is bolted to the carb. Only then will you get an accurate reading of tap flow.
Fitting the biggest valve you can get can cause issues the other way as well as you then causing slight interference with float heights as a bigger one will let slightly more fuel through before it closes off otherwise we would all be running 400 float valves and the only off the shelf kit that is recommended to run this that I know of is the super Monza.
Do you not see what I am saying?
Its obvious that the pipe should be flowing more than what is required at the needle valve, only a moron wouldn't check that first. Stating which kit requires which valve is rather short sighted unless you are referring to the kits in standard format, a standard ts225 running down the motorway reving at 7000 rpm will require less fuel through the float valve than a tuned ts230 running down the motorway at 8500 rpm.
I was just highlighting the fact why we all dont run the biggest needle valve available by stating that the only scoot set up i have come across requiring the biggest valve is the sm not saying if you have a TS1 you should run this needle valve and that needle valve??????rondord wrote:Its obvious that the pipe should be flowing more than what is required at the needle valve, only a moron wouldn't check that first. Stating which kit requires which valve is rather short sighted unless you are referring to the kits in standard format, a standard ts225 running down the motorway reving at 7000 rpm will require less fuel through the float valve than a tuned ts230 running down the motorway at 8500 rpm.
The rest of your post i pretty much agree with and just highlights my point?
We are in agreement then. I was just trying to stay on topic (float needle+valve) 