Cutting out after high speeds
 

So today I am on my way home from a ride, and came around a back road. I got up to about 145mph and started to slow down a little. Then the bike started cutting out. I pulled over, and while slowing down, the bike died. It acted like it was starving for fuel. I did a search and after reading through 6 pages of results, I got nothing.

Anyone else seen this before?

There are a couple of threads about this recently. Several solutions were offered but I'm not sure any conclusions were reached.

Check the carb bowl vent hoses...should be pointing down slightly to avoid trapping gas.
Check the tank vent line. Again, should have downhill flow to avoid trapping gas.
Possible gummed up carb jets...do a good carb clean.

That's about all I have to offer. Good luck.

Just had the carbs off. Clean as a whistle. Will check the carb hoses. Thanks. I'll report back with what I find. I know the tank vent hose is venting. When I did the carbs, I had a nearly full tank and gas was pouring out the bottom of the bike from tipping the tank up to disconnect/re-connect everything. I have only had the bike for a little more less than two weeks, and am getting comfortable on it, so I have started to open it up a little. I'd hate to have to chase down a problem that the PO left me.

Edit to add: My bike is a CA bike, with all emissions/PAIR stuff removed. There are no hoses on the vent tube to speak of. I am going to install some, but I doubt thats going to fix it. I had already ridden about 70 miles today from a full tank, and the majority of it was hard riding. I am wondering if it was runing out of fuel..... I made it another 8'ish or so mile home after it happened, and there is still fule sloshing around in the tank.

Check the side stand switch ;)

When you had the carbs off, did you remove the jets and check for daylight through the orifices?

I dropped a cylinder a little over a year ago, only to discover #2 carb pilot jet was completely plugged up. I had to soak it in carb spray for 30 minutes, then blow it out with compressed air to clear it. The stock 45 pilots are tiny.

After reading 8541hawk's post, I was assuming that it was running now. If it cranks but won't start, you need to go back to the basics...spark, fuel and compression.

No it runs. I rode it home from where it happened. When I had the carbs off, I cleaned everything up. I soaked the jets in MEK. The reason I did it was for a popping out the carbs, and that issue is solved now with some synching and adjusting the pilot screws/needles. Just a little background on me. I spent 9 years as a wrench for the auto dealerships all over the contry before I changed careers, so I am not noob who can't figure his as from a hole in the ground. I know enough to figure this thing out, but this one is puzzling me. I don't really want to take it back up to that speed on the street again, I can't afford a ticket because of the line of work I do now, and I don't want to tear the bike apart at the track. I plan on doing a track day next month with it.

When I had the bowls off, they were clean, spotless! But I was unable to find a fuel filter anywhere. It felt like I was having an issue where a fuel filter would be plugged. Is there one on these bikes? In the petcock maybe? The fuel lines are HUGE so I know thats not an issue. But I am a little puzzled I wasn't able to find a filter anywhere and the bowls were spotless.

Not trying to be condescending, but as a tech you know it's tough to do a long distance diagnosis.

Yes, the only filter is a sock type on the fuel petcock/pick-up.

Oh I know. Sometimes we all need to be reminded to check the basics. And it's hard to tell emotions from reading text. I am going to take the tank back off tomorrow and check the filter(sock) in the petcock. The bike has about 45k miles on it, and I doubt it has ever been looked at. There is no rust in the tank, but you never know what could be on/around the sock.

Sigh. I hate taking the tank off.

Well you had the carbs out did you also pulll & clean the emulsion tubes?

And if so did you keep them separated as they are different for each carb.

Attachment 11785

Service manual calls that the "Needle jet holder?" I had the carbs dissassembled down to everything I could take out of them. I left the jets in the "needle jet holder," but had the holder out for cleaning and inspection. When I had them out, after soaking in MEK, I ran a piece of wire through everything to make sure I had everything out of the jets, then flushed with MEK and then carb cleaner, then compresed air. I didn't think it necessary to take the jets out, just a good cleaning and inspection. I also dissassembled/re-assembled one at a time because I didn't want to mix/match parts. I didn't put anything but MEK/crab cleaner/air in the carb itself.


I am taking my son and wife to the Strawberry Festival in a few minutes. But when I get home, I'm going to take the carbs back off, check everything again, and put them back on. I am also going to drain the tank and remove the sender and petcock and inspect that stuff as well. I have a feeling I am having a flow issue. The bike started up and ran fine after reciveing my ticket for doing 67 in a 50. Good thing he didn't see me a mile earlier ir I might have gone to jail!:shock: Thats the reason why it's going to become a track bike. More later. Walking out the door for the festival.

Needle jet holder, emulsion tube...... one in the same.
You might want to separate the jet from the holder to make sure there is no gunk in there.

Also I would be real careful with the wire through the holes. The emulsion tube brass is pretty soft and the hole size is critical. That is why I just blow them out with air after the cleaner. If I can't get them clean that way, I just replace them.

Just got back from the festival and am going to start working on the bike. Just to re-iterate, it only happened *after* zipping along for a few at high speed/high load. It got there no problem, which is what leads me to belive it's a starvation issue. But, I am going to pull everything off and have a peak anyways.

I think I may have found my problem. There is a vacuum line taht goes to the petcock that looks like it's missing. What does vacuum applied to the petcock do? I thought read somewhere in the service manual that in order to test flow, you need to apply a vacuum to the petcock?


Edit to add: So after looking through the forums real quick searching "petcock" I found out hopefully what my problem was. I ran a line from the rear intake port to the pet cock. Hopefully this solves the issue. I will have to wait and see at a track day. I don't need any more tickets.

The nipple that sticks out the bottom of the petcock, pointing straight down from the tank, is the diaphragm vent...it should remain open. The vacuum hose goes on the nipple that sticks out the left side of the petcock.

PVLIR?

Yup, thats the one I ran a line to. Took it out for a quick ride, but I didn't open it up to check. Maybe tomorrow I'll go find an empty road somewhere and see if it's fixed. Problem is, it's about a 1/2 hour to get to any country/ope roads. Bummer, I might have to go for a ride after I drop off junior at pre-school.

If you figure out the problem let me know. I have the same problem bike cuts out at 145mph and stalls. I cleaned the carbs too. Checking petcock also.

That was more than a little unclear... ;)

If you did run a vacuum line to the nipple on the bottom, that's wrong... Remove it before you cause a problem...

If you did run a line to the nipple on the middle of the vacuum bell, and there was no line to begin with, I really, really would recommend you rebuild your petcock, since if there was no line, it shouldn't open and supply fuel...

Unless it's broken... Then it supplies fuel with or without the line, and the line won't really do any difference...