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Engine cuts out at 80mph

cafeken

CB750 Addict
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westplam
Ok so the bike runs great but if I'm running down the high way at 80mph or so after 15 minutes she stalls out runs out of fuel I have to pull over and wait a minute and it start back up at run fine the rest of the day but she won't do the stall out at 60-70 mph is this a tank vent problem. The carb are clean and jetted right need some help
 
what type of tank? if you think that it may be the vent,,try putting tape over the hole and punch a small hole in it. run it and see what happens then. if that doesnt work it could be something else. have you taken the petcock off and looked at it?,,there may be sediment in the tank that clogs it for a moment and falls back off when you shut it down or if you have an external filter an air bubble or even old gas hose that is swollen internally and getting sucked shut.
 
It's a factory 1978 Honda tank that's on the bike I believe the gas cap as vent in the tank but I never did check to see if it's clogged and I never changed the fuel lines of that could be a good point to start
 
not yet i got a new air filter box that's thicker so i wont get the lean condition on the two inner cylinders so i had to re jet the carbs and with the weather down here i have not finished the tuning on the bike yet and ive been trying to pick up a 03 cbr954rr that a got for a everyday driver but ill keep you posted
 
I have an 03 CBR954rr...I bought it new:) Love the bike and like the looks better than the new ones. Have had no problems with it and wouldn't trade it for the world.
 
I have an 03 CBR954rr...I bought it new:) Love the bike and like the looks better than the new ones. Have had no problems with it and wouldn't trade it for the world.
i just built a 1994 cbr900rr for a friend it came out bad ass it was my first time on a modern bike so all i can say it i fell in love the 954 deal fell through so im looking for another cbr or im liking the vfr with the single side swing arm
 
I had a 94 900rr too!! It was my first sport bike. Put a 98 motor in it though because they were bigger and had about 10hp more. The things we do for a couple of measly HP:laugh: I have seen the vfr swingarm swapped onto the earlier cbr900's.
 
I had a 94 900rr too!! It was my first sport bike. Put a 98 motor in it though because they were bigger and had about 10hp more. The things we do for a couple of measly HP:laugh: I have seen the vfr swingarm swapped onto the earlier cbr900's.
i have to its sick

so here's an update on the bike i think i got it fixed just need some dyno time to get it all tuned in and ill be good to go
 
i just built a 1994 cbr900rr for a friend it came out bad ass it was my first time on a modern bike so all i can say it i fell in love the 954 deal fell through so im looking for another cbr or im liking the vfr with the single side swing arm

First modern bike huh? You should try riding one that's only a few years old. It's crazy how much motorcycles change every 10 years or so.

i have to its sick

so here's an update on the bike i think i got it fixed just need some dyno time to get it all tuned in and ill be good to go

So what did you do to fix it? Petcock filter, fuel line, air filter, and re-jet? You won't know which one of those fixed your problem. :shrug:
 
...
So what did you do to fix it? Petcock filter, fuel line, air filter, and re-jet? You won't know which one of those fixed your problem. :shrug:

i think it was a little of all of it. Add a new fuel line and inline filter the air filter box i had was to small so i got the right air filter box. Installed it and then had to re-jet the bike with 120 jet and shim the needles up 10
thousands then adjusted the air mixture screws. after a three hour test ride i think i have it fixed.
 
Well I guess as long as it's fixed then that's what counts. :) I guess you know it was a tank venting issue. How did that little fuel filter look when you replaced it?
 
How did you shim the needles up 10 thousands? That doesn't even seem like much considering the spacing on typical adjustable needles.
 
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