Bike will only run on prime?

[Sufyan]

This morning riding into work, the bike stalled on freeway. I had enough gas. But on a whim I tried to put in prime. After half a minute or so, it fired right up. So, while again riding, i changed it to on and it started to die. I also tried to put it in reserve and it was still stalling. Put it in prime and it ran fine. Any idea what could be the issue? Also, running it on prime could cause any problems?
After I reached work and shut it off, I switched it to on, so as to not flood the engine.
Any thoughts?

One more thing, what takes precedence? Reserve or Prime? If the bike is in reserve does Prime draw gas or not?

[BeekMan]

Perhaps a vacuum hose has come off or cracked? That's the first thing I'd check.

[pitbull76]

Perhaps a vacuum hose has come off or cracked? That's the first thing I'd check.

+1 That'd be my vote too.

[blkpitbull]

Re: Bike will only run on prime?

Any idea what could be the issue? Also, running it on prime could cause any problems?
After I reached work and shut it off, I switched it to on, so as to not flood the engine.
Any thoughts?

?

I agree with Beekman, and pitbull76 in that your vacuum line is comprimised in some way!!

And your bike will probably foul out the plugs if you run it in prime for to long.

[NY Kat]

yup vaccum hose.

[WildKat]

yup what they said...and trust me from experience, you'll foul out the plugs for sure if you run it on prime with any kinda regularity. #-o

most likely the hose has worked it way loose I would think, if it was cracked you probably would have started to notice it before now, instead of all of the sudden.

[Sufyan]

Alright, thanks for the info guys. I'll try to look into it today evening and see if the hose has come unhooked or something.

The other question: What takes precedence? Reserve or Prime? If the bike is in reserve does Prime draw gas or not?

[zleviticus]

Alright, thanks for the info guys. I'll try to look into it today evening and see if the hose has come unhooked or something.

The other question: What takes precedence? Reserve or Prime? If the bike is in reserve does Prime draw gas or not?

huh?

Reserve is ..well your reserve tank and works like the main tank in that it only draws gas when it is under vacuum... while the prime allows gas to flow freely under vacuum or not... so I don't know what you are referring too when you say "precedence." Prime used when sitting for a period of time.. On for general riding.. then reserve when you are running out of gas when on on...

[Sufyan]

huh?

Reserve is ..well your reserve tank and works like the main tank in that it only draws gas when it is under vacuum... while the prime allows gas to flow freely under vacuum or not... so I don't know what you are referring too when you say "precedence." Prime used when sitting for a period of time.. On for general riding.. then reserve when you are running out of gas when on on...

Hmm ... I'll try to reword that.
What I was trying ask is if the bike is in reserve, then will gas flow into the carbs if the petcock is set to Prime?

[zleviticus]

ahh i think i see what you are asking... does prime use the hose in the for the reserve or the main? hmm good question

[Sufyan]

Well, I just finished putting her back together. The vacuum hose (i think) was a little loose. Around half an inch off. I tightened that and she was running fine. Havent gotten yet to ride her for a while. Will come to know tomm if that was the problem or not.
Well, the petcock has 3 connections coming out. One goes via a filter to the carbs, so I am guessing thats the fuel. Another one (one I tightened) comes from the opposite side of the bike (if you are standing facing it) again goes to the engine. The third one towards the front of the bike was empty. What is that supposed to go to? Or is that the actual vacuum one I am missing?
Oh and if its makes a difference, mine is Cali model.

[Venom]

I know someone that had this problem, no names at this point. And he ran his bike on prime for the longest. He just said "It runs fine on prime." And yes it was the vacume hose that was off or loose.

[BraadaJim]

I know someone that had this problem, no names at this point.

Well by this point in the thread I think you've figured out...IT'S VACUME.

This is a pre98 correct?

Your petcock should have three outlets. As you are looking at it from the knob side the two nipples left and right (front and back if your sitting on the bike) are for fuel. Your lines will only fit one way but the left nipple feeds carb 1/2 and the right one will feed 3/4. The nipple out the back of the petcock that is smaller is for your vacume. it runs across the top of the motor and to the outside of carb 1.

Fuel flow.. think of it like this. Prime is all gas all the time. On and reserve both lead to the same place and are like two straws side by side only one is cut shorter. The taller one (ON) feeds off the top of the tank where the fuel is clean. If you run low on fuel you can switch to the shorter straw (reserve) to get fuel at the bottom. It's not mud, it is just more likely to have dirt in it but sometimes it's dirty gas or walking.

[md86]

2 of the hoses are fuel , that'd be the big ones on the either side of the petcock (one in front , one in back) . The one in the back of the petcock (90* to the other 2) is the vacuume line , and it's a little smaller . Usually they seem to have clamps on them , too . Mine haven't for a while though ... Now , reserve is just like on in that no fuel will flow if there's no vacuume . You could pull all the hoses in either reserve or on with bike off and no gas comes out . No position takes "precedence" really . Think of it like this...the petcock has a tube that runs up into the tank . The top of the tube is where gas goes through in "on" . On prime , the tube is bypassed , so when the fuel level's low , gas still gets through , just a different route . Prime is always on no matter what . Good way to flood your engine if your floats aren't doing their job . If they are , then no harm done . As stated , that line is most likely the cause , and the easiest to fix . However , if that don't fix it , then your petcock may be bad . They can be rebuilt or replaced relatively painlessly (time-wise and $$-wise) . It'd proabably be easiest to get a hold of $K$ for another one if that proves necessary .

[md86]

I know someone that had this problem, no names at this point.

Well by this point in the thread I think you've figured out...IT'S VACUME.

This is a pre98 correct?

Your petcock should have three outlets. As you are looking at it from the knob side the two nipples left and right (front and back if your sitting on the bike) are for fuel. Your lines will only fit one way but the left nipple feeds carb 1/2 and the right one will feed 3/4. The nipple out the back of the petcock that is smaller is for your vacume. it runs across the top of the motor and to the outside of carb 1.

Fuel flow.. think of it like this. Prime is all gas all the time. On and reserve both lead to the same place and are like two straws side by side only one is cut shorter. The taller one (ON) feeds off the top of the tank where the fuel is clean. If you run low on fuel you can switch to the shorter straw (reserve) to get fuel at the bottom. It's not mud, it is just more likely to have dirt in it but sometimes it's dirty gas or walking.

Damn the man , beat me to it !