Stalls at highway speed - looking for direction

[a747freak]

It's not filling the bowls when the petcock is "ON" and the bike is not running, the bowls will only be filled when the bike is off if it's in the "PRIME" postion. After restarting by popping the clutch, it's not at highway speeds and gives the bowls and chance to catch up.

As Ed, said, valve clearance will not cause a bike to stall, unless you bend a valve at the same time...I imagine that would cause a stall, permanently.....

Are you running an extra in-line filter ?

No inline filter, and the petcock filter is intact. As I mentioned, I did clean the carbs as best as I could with carb cleaner, tearing them down to the tiniest of pieces and cleaning all of the gunk out. I didn't soak them because I didn't have the materials to do so, and I didn't replace any o-rings because I didn't know they were so easy and cheap to get. However, none of the o-rings looked bad anyway. I removed them all before spraying carb cleaner as well so nothing would dissolve. I also used a small needle to clean out the jets and didn't put it back together until it was perfect. I suppose there is the possibility that some rust made it to the carbs from the tank, and the main jet(s) may need to be cleaned again. I know it doesn't do much for rust, but I've added SeaFoam to my gas for the last 3 or 4 tanks. I have not adjusted the mixture on my carbs (since I read it was factory-set), but after reviewing other posts I think it needs to be done. One of my pipes is turning quite blue, which indicates a lean mixture, correct? The other pipe is fine. I didn't do a true plug chop at WOT because I started it again before i took the plugs out, but when I did look at the plugs one was almost white, the other was brown. So I will adjust the mixture today and take it for another spin. (Turn the screws in all the way, then out 3 turns, right?). Even if this has nothing to do with the problem at least it should run better.

One other question, what grade of gas do you all use in your bikes? Thanks.

Steve

[Larry D]

As stated before, a proper carb dip is the way to go. There's been many a story here of folks "cleaning" the carbs several times before dipping and rebuilding them correctly. You can't find a can of Berrymans where you live ?

Is the exhaust that's turning blue the same one that cuts out ? In your case it may have turned blue from the lack of fuel to that side and running a bit lean. And yes, lightly seat the adjustment screw and turn out about 2 1/2- 3 turns. These idle air/fuel screws only affect the mixture at idle to about 1/4 throttle, so, it's probably not the issue with dying while pushing it at highway speeds.

Did it look like anyone had been into the carbs before you ? When you had them apart, did you look at the jets to see if they're stock ?

Oh... and gas grade doesn't matter.

[FlyingSteve]

It's not filling the bowls when the petcock is "ON" and the bike is not running, the bowls will only be filled when the bike is off if it's in the "PRIME" postion. After restarting by popping the clutch, it's not at highway speeds and gives the bowls and chance to catch up.

As Ed, said, valve clearance will not cause a bike to stall, unless you bend a valve at the same time...I imagine that would cause a stall, permanently.....

Are you running an extra in-line filter ?

When you crank the engine, the vacuum pulls the petcock open. He said he was sitting on the side of the road and could not get the bike to restart for 5 minutes. If you are cranking the engine, the petcock is opening and letting fuel into the bowls. If it was fuel starvation, the bowls would refill while cranking and the bike would restart in a few seconds. Even if you did this while still rolling down the highway with the clutch pulled in, it would restart and then die shortly thereafter as the bowls drained out again.

And what magic do you think is going to happen when you dip the carbs in Berryman's versus using carb cleaner and pulling the carb completely apart and thoroughly cleaning the jets/passages with a needle and carb cleaner?

If you spray carb cleaner into all of the passages and you get equally good flow out the exit, then the carb is clean.

I recommend that before you go and rip everything apart that you do more diagnostic tests. Run the bike on the highway till it stalls, coast to a safe place and then pull out your tool kit. I'd remove the drain plugs from the bottom of float bowls to see if fuel comes out and see how much comes out. Be sure that you are getting good spark while cranking as well. The best time to diagnose what is wrong isn't while the bike is sitting in your garage and running fine, but after it stalls out.

[Larry D]

When you crank the engine, the vacuum pulls the petcock open. He said he was sitting on the side of the road and could not get the bike to restart for 5 minutes. If you are cranking the engine, the petcock is opening and letting fuel into the bowls. If it was fuel starvation, the bowls would refill while cranking and the bike would restart in a few seconds. Even if you did this while still rolling down the highway with the clutch pulled in, it would restart and then die shortly thereafter as the bowls drained out again.

And what magic do you think is going to happen when you dip the carbs in Berryman's versus using carb cleaner and pulling the carb completely apart and thoroughly cleaning the jets/passages with a needle and carb cleaner?

If you spray carb cleaner into all of the passages and you get equally good flow out the exit, then the carb is clean.

I recommend that before you go and rip everything apart that you do more diagnostic tests. Run the bike on the highway till it stalls, coast to a safe place and then pull out your tool kit. I'd remove the drain plugs from the bottom of float bowls to see if fuel comes out and see how much comes out. Be sure that you are getting good spark while cranking as well. The best time to diagnose what is wrong isn't while the bike is sitting in your garage and running fine, but after it stalls out.

That is the case if the petcock is functioning properly, which it may be if you can cruise around with no issues. The only time it happens is when pushing the bike at near WOT.

Magic ??....there is no magic. Only stating what I've read time and time again. As you seem to know there are very tiny passages that *I* believe simply spraying carb cleaner in will not get to effectively enough. I've always dipped in Berryman's...so...that's what *I* recommend. I've never had an issue afterward.

Good idea. Run it until stalls, pull over and see how much fuel you get out of the bowls. Of course, they both should have the approximately the same amount. Take a wrench and a little tupperware container that will fit under the carbs.

Is the inside of the tank all rusty ? Do you think perhaps some crud has re-entered the carbs to cause this problem ?

Seems odd to me that you can tool around town at minimal throttle opening with no issue and yet when opening her up she dies out. How long do you have to push it before it croaks on you ?

Let us know what you find.

[a747freak]

That is the case if the petcock is functioning properly, which it may be if you can cruise around with no issues. The only time it happens is when pushing the bike at near WOT.

Magic ??....there is no magic. Only stating what I've read time and time again. As you seem to know there are very tiny passages that *I* believe simply spraying carb cleaner in will not get to effectively enough. I've always dipped in Berryman's...so...that's what *I* recommend. I've never had an issue afterward.

Good idea. Run it until stalls, pull over and see how much fuel you get out of the bowls. Of course, they both should have the approximately the same amount. Take a wrench and a little tupperware container that will fit under the carbs.

Is the inside of the tank all rusty ? Do you think perhaps some crud has re-entered the carbs to cause this problem ?

Seems odd to me that you can tool around town at minimal throttle opening with no issue and yet when opening her up she dies out. How long do you have to push it before it croaks on you ?

Let us know what you find.

Not sure that I'll be able to check it tonight, its a little rainy out, but I can say that it takes sometime at WOT to die, probably about 5 minutes. The tank has some rust in it, but not a whole lot from what I can see. When I removed and cleaned the petcock a few months ago the filter didn't seem clogged so I assume it's pretty clean. The bike runs great around town and on short hops on the highway. When I do open it up fully in 6th gear, it doesn't feel as powerful as it should be, but then again it's a 250 and I weigh about 200 lbs so going 75 seems pretty alright to me. I will check the fuel from the bowls as soon as I can. As far as dipping the carbs..I do plan on it, really I do, but again I cleaned them super thoroughly. it also has new airbox seals, intake books, and exhaust gaskets and a new, lightly oiled foam air cleaner.

[Danjal]

Im with ness here. I think its possibly the petcock starving it from fuel. If it starts again turn it on prime and see if it goes away. After that pull your tanks, remove any filters inline and see if it goes away. Other then that try popping your gas cap open once it does this too. It might just be your breather for your tank too causing a vac problem.