Stock petcock is a piece of JUNK. :mad:

slowinthestraights · July 22, 2007, 02:29:34 AM

So the other night, im cruising along on the freeway, I had been on for about 2 minutes, going 75~. All of a sudden the bike just DIES. I have to pull over into all of the shaZam! on the side of the freeway, I try cranking it over, nothin. Put it on reserve, nothing, nothing. I could get it to start, and all it would do was sit at 1200 rpm, and I had to hold it at 1/2 throttle to keep it there. I figured that I switched up the lines when I had the tank off and actually ran it out of gas. I walked it backwards about a 1/4 mile, down the offramp and to a gas station. Popped open the tank, and it looked low.. so I filled it up. Seemed to work fine after that.

On the freeway TONIGHT! Cruising along at 75-80, been on the freeway for about 5 minutes, the bike sputters, and then dies. I pull in the clutch and coast along the emergency lane AGAIN (again, didnt pick up anything in the tires luckily) As I am rolling along, I try to start it, in reserve, in ON.. nothing.. finally just do it in PRIME and it works after cranking it for quite a bit. I get off and go to a gas station. The tank is probably about 1/3-1/2 full, no reason for even the main to run out. I put in a gallon and a half and left the petcock on PRIME. After trying to find a way back home besides the freeway, I give up and get back on it. I was on the freeway for 15 + minutes, until i got to an area I was familiar with, and got off. I didnt have any problems with it. I was also noticing a flatspot midrange, and a weak top end.. With the petcock on prime, those dissapeared.

Moral of the story? Trash your stock petcock, and buy an 04 CR250FX (i think, check bikebandit) petcock for $26 from BikeBandit. 2916036-001 is the bikebandit part number.

I will be running my bike on PRIME until I can get that, Its not only a pain in the butt to have these troubles with the unecessary vacuum petcock, its DANGEROUS to have the godddam bike shut off while you are heading down the highway with no warning!

Affschnozel · July 22, 2007, 02:49:23 AM

Although I hadn't had issues with stock petcock I agree it's a PITA ,too much tubes , the main and reserve...and the vacuum hose....blah

For me taking the tank off and on is the most difficult procedure, never mind replacing shims...

dgyver · July 22, 2007, 06:35:47 AM

The vacuum is needed to prevent someone forgeting to turn off the fuel, which if they have bad float valves, the carbs will flood the motor.

The problem with the stock petcock is the check valve in the vacuum port. It will turn to goo from gas fumes and will partially or completely block the the vacuum, which is required to operate the diaphram to allow fuel to flow.

DaxFX · July 22, 2007, 10:46:12 AM

when i got my bike ! was missing .. i have the 2 gas line to a splitter

some1 can show me a photo of how is supouse to be . mine looks like a drug user was the mechanic man ..

slowinthestraights · July 22, 2007, 11:18:27 AM

Quote from: dgyver on July 22, 2007, 06:35:47 AM
The vacuum is needed to prevent someone forgeting to turn off the fuel, which if they have bad float valves, the carbs will flood the motor.

The problem with the stock petcock is the check valve in the vacuum port. It will turn to goo from gas fumes and will partially or completely block the the vacuum, which is required to operate the diaphram to allow fuel to flow.

Thanks. I am aware...

People should just know, either take your stock petcock apart and verify it is in good shape, replace it, or buy a different one.

frankieG · July 22, 2007, 04:36:21 PM

could simply be the filler cap vents need cleaning

galahs · July 23, 2007, 12:02:44 AM

I'm thinking of ditching the frame mounted petcock and making up my own simple reserve system.

Two pipes from the tank, reserve pipe with on / off valve

Two pipes joined with t connector

single exit pipe with master on / off fuel valve

single pipe connected to carbs t.

Suzuk-E · July 23, 2007, 12:43:51 AM

lol @ ""drug user was the mechanic man.

DaxFX · July 23, 2007, 08:02:17 AM

yes .. me !!!!

simoniz · July 31, 2007, 06:49:25 PM

I like the look of the CRF250 fuel tap - and I am also having a similar fuel starvation problem on my '89, which was also laid up a while before I got it, with old gas in the tank. It ticks over fine but bogs down when I open the throttle out on the road. I drained it and put in fresh gas, and checked the tank gas cap for blockages.

The CRF fuel tap is $21.21 at Powersports Pro, by the way. But I don't see a vacuum line connection on it, so do you just tie that tube off and ignore it? Does it just run as a gravity feed tap instead?

NiceGuysFinishLast · July 31, 2007, 06:51:25 PM

Quote from: simoniz on July 31, 2007, 06:49:25 PM
I like the look of the CRF250 fuel tap - and I am also having a similar fuel starvation problem on my '89, which was also laid up a while before I got it, with old gas in the tank. It ticks over fine but bogs down when I open the throttle out on the road. I drained it and put in fresh gas, and checked the tank gas cap for blockages.

The CRF fuel tap is $21.21 at Powersports Pro, by the way. But I don't see a vacuum line connection on it, so do you just tie that tube off and ignore it? Does it just run as a gravity feed tap instead?

Yeah, it's a gravity feed. Also, if your bike was laid up for awhile, just changing the gas won't be enough. You'll need to clean the carbs, that should help a good bit with your bogging issue.

Jay_wolf · July 31, 2007, 06:57:29 PM

i left my bike sitting for 9 months, twice in the space of 2 years ,. , When i got banned . and i started her. after fresh fuel , worked fine . i dont seem to get these problems ,never had fuel stavation , 1996 , must be the good model

simoniz · July 31, 2007, 06:59:15 PM

Thanks for the quick answer. The previous owner (who runs lots of classic bikes) said he cleaned the carbs before I got it, but I will do them myself again to be sure. That Honda gas tap is a bargain too, and the stock one is a total PITA, as has been noted here!

dgyver · July 31, 2007, 07:04:04 PM

When eliminating the vacuum, you will need to cap the line or the tee. Otherwise you will be sucking in additional air into the left carb.

simoniz · July 31, 2007, 07:06:20 PM

Quote from: dgyver on July 31, 2007, 07:04:04 PM
When eliminating the vacuum, you will need to cap the line or the tee. Otherwise you will be sucking in additional air into the left carb.

I can do that! Thanks for the tip.

slowinthestraights · July 31, 2007, 07:18:23 PM

My CRF Petcock should be here soon, FINALLY.

The stock one has left me stranded countless times. No more.

ben2go · July 31, 2007, 07:54:51 PM

Quote from: slowinthestraights on July 31, 2007, 07:18:23 PM
My CRF Petcock should be here soon, FINALLY.

The stock one has left me stranded countless times. No more.

keep us posted on how it turns out.I may need to do that swap

slowinthestraights · July 31, 2007, 07:56:40 PM

Ill put some pictures up. If i get the stuff tomorrow or early thursday, I can do it all then. But I will probably end up doing it all sunday.

ben2go · July 31, 2007, 07:58:06 PM

Quote from: slowinthestraights on July 31, 2007, 07:56:40 PM
Ill put some pictures up. If i get the stuff tomorrow or early thursday, I can do it all then. But I will probably end up doing it all sunday.

Kool! Thanks!

Nikolas · July 31, 2007, 08:00:28 PM

You can also convert your stock petcock to non-vacuum for almost nothing.

News:

Stock petcock is a piece of JUNK. :mad: