Question about on/pri/res positions

[Ololorat]

Hi guyz
I have a question:
In cold weather I couldn't start my bike and just tried PRI position and engine started to work. From description in manual it doesn't look that PRI position could help (I use my bike often and didn't drive just for couple of days so there was no lack of fuel in carburetor).
Does it mean that in ON position something can be wrong?
Also in manual it is said that "Upon starting the engine, be sure to return the fuel valve to the ON position". So is it going to be a problem if I drive when valve position is PRI (I read manual after doing that)

[mrlmd1]

In the Prime position the valve in the petcock is open and fuel flows by gravity into the carb.
In the Run position the valve is opened by the vacuum generated by the engine, allowing fuel to flow. The fuel flow is shut off when the engine is not running. (There is no Off position, the fuel flow is off when the engine is off).
In the Reserve position the valve is also opened by the vacuum allowing fuel to flow, but it is flowing through another shorter pipe in the tank.
You should not have to have the petcock in the Prime position unless there is something wrong with the petcock (unlikely) or if there is no vacuum to the petcock.
Check that the vacuum line is attached to the petcock and that there are no cuts or leaks in it.

Prime should have nothing to do with starting the bike unless the bike has been sitting for a couple of months and there is no gas in the carb. You only put it there for a minute or so to fill up the carb, not to run the motor.
You should not leave the bike with the engine not running with the petcock in Prime - if the needle valve in the carb is dirty or leaking, you will be dripping gas all over the floor.

After the bike starts, does it run in the Run position?
A more basic question is, is there gas in the tank?

Are you using the choke properly to get the bike started in the cold weather, and even for the first start of the day when it is warm?

[raul10141964]

the cold weather harden the rubber houses an that can lid to a vacuum leak preventing the petcock to open

[Ololorat]

motorcycle worked well after starting and changing PRI to ON and there is some fuel in the tank


I just wanted to know if I already damaged something when didn't change PRI position to ON while driving
and it sounds strange for me that I was able to start it in PRI and wasn't in ON (so may be it is a sign of something wrong)

Sorry for stupid questions. I am a newbie female biker so I know nothing about technical maintenance of motorcycles)

Also yesterday night was very cold so I couldn't start the bike at all and probably uncharged the battery while trying. And today was warmer but I also couldn't start it in the morning cuz of low battery so my neighbor pushed the bike while I was on the 1st gear and I released the clutch and run to work. I hoped that on the way to work my battery would be charged but that didn't happen and I couldn't start it in the evening also)
I had a slope so was able to start it using inertia and now I am thinking about what should I do to the battery: do I need to charge it or just run for few more miles.

thanks

[Water Warrior 2]

Just a female newbie. Not a problem. We get a lot of newbies of both genders searching for answers to questions. You likely need to charge the battery to eliminate the lack of power first. A Battery Tender is a small smart trickle charger ideal for bikes. A great investment for all riders.
Getting back to the fuel switch. There is a vacuum line and a fuel line on it's back side. One goes to the carb and the other to the engine vacuum source. If this V line is brittle or hard it may not be sealing properly at either end. It may have a crack in it as mentioned earlier. You can pull it off and use it as an example at your local auto parts store and they will have a replacement for you. What they need is the diameter and will cut off a proper length for you. Make sure you specify vacuum line.

[Ololorat]

So today is 53F I could start my bike in the morning but only when PRI was turned on
after I started I change it to ON position and had no problems to run to work
so I'll check vacuum line this evening
Thanks guyz
My Suzuki 250GZ is 2003 and has 14k miles so probably there should be a lot of stuff to fix.

[alantf]

I could start my bike in the morning but only when PRI was turned on
after I started I change it to ON position and had no problems

This is starting to sound more like the float bowl emptying while the bike is standing. Before trying to start it, do you notice any fuel under the bike? or is the carb damp underneath? If the bike runs ok in "run", once you use "prime" to fill the bowl, then I don't think that the problem could possibly be the vacuum hose. Seems like you're going to have to strip the carb and find out. :)

[Ololorat]

and also there is no such problem when weather is warm (I would say more than 60 F)

[alantf]

Errrrrrrr...... Your location says "United States". Can you put your location, so that we know that you're a real person? :)

[Ololorat]

Ok I live in Birmingham, AL (USA). I just didn't know what exactly should I write as my location (country or city)
how can that prove that I am a real person? :)
I am also not an american and not a native English speaker, so may be I have some errors

I have a "troll" nickname because I used it on couple of other sites and I like it and want to keep but I am not a troll or something, I really want to understand my bike

[Water Warrior 2]

Ok I live in Birmingham, AL (USA). I just didn't know what exactly should I write as my location (country or city)
how can that prove that I am a real person? :)
I am also not an american and not a native English speaker, so may be I have some errors

I have a "troll" nickname because I used it on couple of other sites and I like it and want to keep but I am not a troll or something, I really want to understand my bike
Maybe edit your location to Birmingham Al. so we know where you actually are.

Now just for general info where are you originally from and how long have you been stateside? Your English is better than most folks on the internet.

[Ololorat]

Maybe edit your location to Birmingham Al. so we know where you actually are.

Now just for general info where are you originally from and how long have you been stateside? Your English is better than most folks on the internet.
1)done
2) oh wow) thanks :rawk:
I am Russian and I live in USA for about 3 years total
My bike started with no problems this eveining and position was ON. It was about 58F
Does it make any sense? :biggrin:

[Water Warrior 2]

Heh heh. Maybe you found the right combination of choke and starting procedure to succeed. Or you just held your mouth the right way.

[Ololorat]

I turned choke all the way and so did I in the morning
but it was a cold night and bike was cooler than the air (53F in the morning) and it was a warm day and bike probably didn't cool down to the air temperature (58 in the evening, I checked weather.com)
May be something is wrong with the battery?

[alantf]

AL (USA). I just didn't know what exactly should I write as my location (country or city)
how can that prove that I am a real person? :)


It's just that, in the past, we've noticed that people who come on the site just to cause arguments, quite often put "America" rather than give a specific location. Glad to find that you are a genuine seeker of knowledge. :) :2tup:

[mrlmd1]

I mentioned using the choke way back in the first response to you. You need that for the first start of the day and especially when the weather is cold. With more experience with the bike, you'll figure it out, but there is probably nothing wrong with the bike. (operator error?). Check out the owners manual.

[Ololorat]

Ok, I'll explain again
1) I couldn't start my bike at all when it was very cold (34F or 1C) - I believe that reason is my battery and it is probably same for most bikes
2) I could start it with PRI position when it was 53F (11C) outside (Motor didn't start when it was ON and choke was turned all its way for both situations)
3) Bike started with no problems when it was 58F (14?) and valve position was ON and choke was turned all its way

I am not very experienced but I did more than 1k miles on my bike so at least I know how to start it and I had no problems with it at all when it was warmer weather

[PimpS]

Maybe your idle speed is set too low... I had similar problems, then i figured out that my idle speed settings were way too low... My bike did start, but not at once (even with the choke on), 3rd try was ok but i could here the bike wasn't comfy with it for first moment, then the choke did all the rest...

[alantf]

Maybe your idle speed is set too low...

Idle speed, with the engine fully warmed up, and choke off, should be 1200 to 1400 RPM.

[Ololorat]

Maybe your idle speed is set too low...

Idle speed, with the engine fully warmed up, and choke off, should be 1200 to 1400 RPM.

how to check it? My bike doesn't have a tachometer
When engine is warm and choke is turned off and I don't add any gas with my throttle engine works and doesn't stop

[alantf]

If you can listen to a car, the idle is usually around 850 RPM, so your bike should sound around 1½ times as fast.

[mrlmd1]

My bike used to start within 1 - 2 revolutions of the engine, no matter what the temperature was.
Grasping for straws, here's a few thoughts -
It's possible one of the problems could be a weak battery, magnified by the cold. Does the engine turn over pretty fast when it's cold, or is it slower? If the battery is weak, one of the symptoms is not enough juice to fire off the spark. It does start when you push it, right? You might keep the battery on a tender or trickle charger (with the plug-in pigtails) at night when the temp drops.
What weight oil is in the bike now? In the colder weather, maybe your bike would like a thinner, lighter weight oil.
Make sure your carb is clean by adding 1 - 2 oz/gal of gas of Berryman's B12 Chemtool or Seafoam into the gas tank and run it through, then add 1 oz/gal of gas of either into the tank every 3 or 4 fillups to keep the carb clean.
The idle speed is just something you have to listen to, or ask someone else to listen to it, You adjust the white knob below the carb either way to speed it up or slow it down, after the engine has thoroughly warmed up. If your bike runs fine and doesn't stall when you stop at a light, or doesn't sound like it's racing too fast, there's probably nothing wrong with your idle speed and that wouldn't have much influence on the bike not starting in the cold.
I would bet your battery is a little on the weak side. Keep it charged it up and go from there.

[raul10141964]

the chock do not work if you open the gas

[mrlmd1]

Do yo have any idea of when the last time was that the valves were adjusted or checked?

[Ololorat]

I changed the battery, it starts much easier and light is brighter %)
but it is warm weather now so I need it to be colder to check how it really works

[Rookie Rider]

mrlmd1, i think he got over excited bout the battery that he just ignored your question, haha, hey, it happens.