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Discussion in 'Technical and Troubleshooting Torque' started by Pommy, Feb 14, 2008.
What is the PRI used for?
Can someone explain please?
Spoken about in that thread.
It simply primes your fuel line/carbies.
It would appear that I have no off position and that PRI is also off then?
YES and NO
Your 'off' happens automatically when you stop the engine in either "on" or "res" position.
PRI is _always_ON_.
So when I start my bike I should put it on PRI?
Then change to ON?
Seems a bit messy just to ride the bike?
Aslo...the long bit of the handle has an arrow on it - BUT it seems to work opposite of the arrow?!
Resize your text to lower case
On the count of ten, or...
Post Removal is Imminent
Are you for real?
It's used to emphasise, not shouting.
I'm very sure nobody else has a problem with it?
I can't believe your pettiness to be honest.
Seeing as you have the power(and I use that term extremely loosley) if it makes you feel better, remove it.
In the meantime I will continue to try and get some useful help.
Happy now Hornet ? :roll:
In regards to your question, no you don't have to be switching the tap all the time.
The fuel 'on' is done via crankcase vac, once the engine stops no vac = tap off, no fuel
Prime is used on the rare occasions that you do run your tank dry or want to flush your carbys or after any work that need the carbys and lines drained.
So no you shouldn't have to worry about it at all just leave it on 'ON'
That is of course you have gone onto reserve, then make double sure you put it back to ON when you fill up, or your next fuel cough / splutter will be very embarrassing when you find your still on 'Res'
As was stated in the thread I linked earlier, you use prime when the bike has tried to run with no fuel in the line - to prime the line.... if you turn your bike off normally the fuel stops where it is, therefore when you start it the fuel is already there- you need not prime.
Keep your tap set to "On" at all times, unless you hit reserve in which case set to "Reserve" and when you refill set to "On", if your engine stops running completely before you switch over to reserve, or you try and run it without fuel, THEN you use "Pri" (prime) to pump some fuel through the lines.
Thanks VTRBob/Jomo - that's all I need to know.
I am new to all of this and it's all a learning curve but I am enjoying it so far!
I think you've got it but just to make sure, PRI is not OFF. In fact it ON whether the engine is running or not.
Leaving it in th PRI position may fill your pistons and/or crankcase up with petrol.
Just so you know.
A friend got caught out by this once.
His bike had just been serviced and (for whatever reason) had been set to Prime by the mechanic. He rode out of Canberra to intercept me on my trip up from Melbourne... We met up in Holbrook, started riding to Canberra and discovered that when the bike is set to Prime, it's drawing from the reserve line.
Prime is best used to fill the carby(s) if the bike is let sit for a while - Depends on the bike a bit. My 600 cc single starts much easier if I turn the tap to prime for a few seconds before changing to ON, then kick.
Overnight, it's not an issue, but if it sits for a week, then it is, as over a week the carbies seem to lose a bit of their fill, so prime tops them up, prior to a real try for a start.
Otherwise the vacuum operated tap only allows the fuel to flow to the carbies when there is vacuum. The vacuum only exists when the engine is kicked over or the engine is running. I only have so many good kicks, so save them by using prime first if the bike has sat for a while.
The only time I've used pri (prime) is either when I've removed the carbs for cleaning and need to prime them first before trying to start the motor.
Using prime inapropriately is could have distastous consequences, as I did forget to turn the fuel tap back to the on position after I got the motor running. It was left overnight in the prime position, which allowed fuel to flow via the carbs into the motor.
I was fortunate to recognise the smell of pertol, and deduce the reason why, so on removing the fuel tank, then the coils and spark plugs, I turned the motor over with the starter, which blew the fuel, which had collected overnight in the combustion chambers overnight, forcefully out the the plug holes.
The only unfortunate thing was that I was standing on the LHS of the bike at the time, and reaching across to the starter, which put me in direct line of the fuel spray. I still don't know why people sniff it...it tastes bloody terrible. :grin:
Ha Ha - in your eye mate - it could have been worse!