Fuel set to PRI?

[tsdexter]

Finally got all the fairings and front/headlights out.. Just looking over everything, I noticed fuel is set to prime and has been for at least the year I've owned it and probably as long as the last guy owned it. Should I change this to ON or leave it? Will I have any issues setting it to on that may cause me to have to remove fairings on the side of the road to switch back?

[alex.s]

if everything is working correctly, it should be in ON position.

[tsdexter]

Originally Posted by alex.s

if everything is working correctly, it should be in ON position.

Thanks, ill switch it to ON and start it up... Anything I should look out for? Rev it certain amount, let it idle for x mins? Etc..

[alex.s]

if it dies and wont start from lack of gas when the petcock is switched to "on" but works fine in "prime" then it means the vacuum line running to your petcock has a leak or is not connected or the petcock is damaged.

[tsdexter]

Originally Posted by alex.s

if it dies and wont start from lack of gas when the petcock is switched to "on" but works fine in "prime" then it means the vacuum line running to your petcock has a leak or is not connected or the petcock is damaged.

Looks like its OK so far. Started up no issue, idled for a minute or too and revved past 6k several times... Can't tell for sure but sounds like the buzzing sound I was hearing had disappeared with all the fairings off...sweet.

[Bob2010]

I wondered the same thing. When I bought both bikes , I never checked.
I noticed mine was set to PRI and the other was set to ON
I switched both to ON
My bike seems to start up just as quick as the other bike now. Maybe it's just a coinsidence.

[tsdexter]

Originally Posted by alex.s

if it dies and wont start from lack of gas when the petcock is switched to "on" but works fine in "prime" then it means the vacuum line running to your petcock has a leak or is not connected or the petcock is damaged.

I set it to ON 3 days ago and then it sat in the garage for the three days... When I trIed to start it today, it wouldn't go, even with the choke, I tried several times up to 5-6 seconds at a time on the starter or more and nothing. I switched back to prime and held the starter with the choke and it very slowly started going then a really low idle for about 10 seconds then it started to pick up, then I had to run with the choke for 20 seconds or so before I could turn it off..

What do you suggest?

[felo]

Originally Posted by tsdexter

I set it to ON 3 days ago and then it sat in the garage for the three days... When I trIed to start it today, it wouldn't go, even with the choke, I tried several times up to 5-6 seconds at a time on the starter or more and nothing. I switched back to prime and held the starter with the choke and it very slowly started going then a really low idle for about 10 seconds then it started to pick up, then I had to run with the choke for 20 seconds or so before I could turn it off..

What do you suggest?

you shouldnt leave it in the ON position for that extended amount of time

[alex.s]

3 days is not an extended period of time.

old petcocks and floats get grimy and if you leave them sit for a little while the gas dries up a bit and it gets a little cricky. if you want a problem to fix you could rebuild the petcock and carb bowls. or just say "that was an oddly cold start for only 3 days" and carry on normally.

[tsdexter]

Originally Posted by felo

you shouldnt leave it in the ON position for that extended amount of time

I'm not sure I understand...the switch is behind the fairing so whatever position it's in, it will stay that way since I'm not going to remove the fairing everyday. So if I put it to ON it will stay at on for much longer than 3 days...

Originally Posted by alex.s

3 days is not an extended period of time.

old petcocks and floats get grimy and if you leave them sit for a little while the gas dries up a bit and it gets a little cricky. if you want a problem to fix you could rebuild the petcock and carb bowls. or just say "that was an oddly cold start for only 3 days" and carry on normally.

Are you saying when it's switched to ON I should be starting/running it everyday and then I shouldn't have any issues, that was just a bad 'cold' start? So should I still try running it in ON once I'm done all the maintenance and riding often again?

Problem is, I couldn't get it to start without having to switch back to PRI - that would be very inconvenient in the middle of a parking lot or something if I had to remove the fairing and switch it..

[Dano]

I never change the position of my petcock in the new gens.

[NevadaWolf]

Just to give you an idea... I've never changed mine from ON since I bought the bike, which includes the 3 months it sat up on a stand while I was repairing it. Yeah, I'd run it once every few weeks for a bit but that was mostly since I was testing lights and didn't want to kill the battery.

You shouldn't have to be switching it back and forth, especially after only a few days.

Unfortunately, I have no suggestions to offer.

[tsdexter]

Originally Posted by NevadaWolf

Just to give you an idea... I've never changed mine from ON since I bought the bike, which includes the 3 months it sat up on a stand while I was repairing it. Yeah, I'd run it once every few weeks for a bit but that was mostly since I was testing lights and didn't want to kill the battery.

You shouldn't have to be switching it back and forth, especially after only a few days.

Unfortunately, I have no suggestions to offer.

Alright, I'll try running in ON again for a bit and see what happens. Maybe the vacuum line is damaged and thats why the PO put it to PRI instead...

[DaBlue1]

Originally Posted by tsdexter

I'm not sure I understand...the switch is behind the fairing so whatever position it's in, it will stay that way since I'm not going to remove the fairing everyday. So if I put it to ON it will stay at on for much longer than 3 days...



Are you saying when it's switched to ON I should be starting/running it everyday and then I shouldn't have any issues, that was just a bad 'cold' start? So should I still try running it in ON once I'm done all the maintenance and riding often again?

Problem is, I couldn't get it to start without having to switch back to PRI - that would be very inconvenient in the middle of a parking lot or something if I had to remove the fairing and switch it..

The petcock is designed to be in the ON position at all times except when there is a need to get fuel back into the carb bowls after doing maintenance on the carbs.

The petcock is vacuum operated. It should have two hoses attached to it. (1) large fuel line attaching to a larger nipple and (1) a smaller vacuum line attached to a smaller nipple. When the engine is running with the petcock in the ON position, the vacuum opens up the diaphragm to allow fuel to flow. When the engine stops the vacuum closes the the petcock off.

In the PRI position fuel is flowing all the time. You don't want this. When you leave the petcock in the PRI position you are solely relying on the float valves to stop the carbs from overflowing with fuel and possibly leaking past the piston rings into your oil.

If your bike only runs in the PRI position, your petcock is either bad or the vacuum line is not attached properly or has a leak.

To fix it, you need to either see if the vacuum line is attached correctly or replace the petcock. A petcock can be purchased either used or new, and replacement is pretty simple. You will need to remove the fuel tank with the petcock in the ON Position. Once the tank is off, you drain the tank by turning the petcock to the PRI position. After the tank is completely drained replace the petcock then reinstall the tank.


Look in the Directory of all 250R DIY threads to find out how to do it.

[tsdexter]

Originally Posted by DaBlue1

The petcock is designed to be in the ON position at all times except when there is a need to get fuel back into the carb bowls after doing maintenance on the carbs.

The petcock is vacuum operated. It should have two hoses attached to it. (1) large fuel line attaching to a larger nipple and (1) a smaller vacuum line attached to a smaller nipple. When the engine is running with the petcock in the ON position, the vacuum opens up the diaphragm to allow fuel to flow. When the engine stops the vacuum closes the the petcock off.

In the PRI position fuel is flowing all the time. You don't want this. When you leave the petcock in the PRI position you are solely relying on the float valves to stop the carbs from overflowing with fuel and possibly leaking past the piston rings into your oil.

If your bike only runs in the PRI position, your petcock is either bad or the vacuum line is not attached properly or has a leak.

To fix it, you need to either see if the vacuum line is attached correctly or replace the petcock. A petcock can be purchased either used or new, and replacement is pretty simple. You will need to remove the fuel tank with the petcock in the ON Position. Once the tank is off, you drain the tank by turning the petcock to the PRI position. After the tank is completely drained replace the petcock then reinstall the tank.


Look in the Directory of all 250R DIY threads to find out how to do it.

Thanks for the detailed reply.

Would the gas leaking into oil cause very dirty/dark oil? I just did the oil change it was very dark brown... Not sludgy or anything just extremely dark.

[DaBlue1]

Originally Posted by tsdexter

.....Would the gas leaking into oil cause very dirty/dark oil?

No. It may be milky caramel colored, thin in viscosity, and smell heavily of gas.

Dark colored oil can be normal. Black oil can be a sign that the oil has not been changed in a very long time or excessive carbon build up.