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KUNG FU SAND PANDA
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Discussion Starter #1 (Edited)
Vapor lock on the '06 Yamaha Raptor 700's has been a common problem.

Symptom: Intermittent “hard starting” when the engine is hot, usually occurring 5 – 10 minutes after shutting the engine off. Most commonly reported in the Northeastern regions and desert.

Cause: The seasonal gasoline in these areas has lower vapor pressure and subsequently lower boiling point then fuel commonly found in other regions. This allows bubbles to collect in the fuel pick-up tube, causing the pump to temporarily cavitate or vapor lock. The pump will usually prime after several minutes and operate normal again.

Remedy: The fuel-vapor bleed hole was enlarged on mid production units to prevent vapor build up. If you experience a similar compliant, replace the fuel pump with FUEL PUMP COMP. (P/N:1S3-13907-02-00) which has a 0.8 mm bleed hole.

To identify which fuel pump you have you will need to follow the following procedure.

First remove your seat, then you will need to remove the two (2) plastic screws that hold the bottom gas tank cover down.


Next remove the two (2) allen head screws that hold your hood on and remove hood.


Next remove your gas cap and slide your gas tank cover off and reinstall gas cap. Here you will be able to see the fuel pump on the top of your gas tank.


You will have to look very close at the middle of your fuel pump to read you fuel pump part number. Remember, if you have any other number besides P/N 1S3-13907-02-00 you have an early production Raptor and have the faulty fuel pump. I penciled over the part number so you know what to look for.




Below is a factory Yamaha service bulletin on the fuel pump problem.

 

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when taking off fuel cap...the gas seems to be "boiling" this is actually from pressurized air...when you take the cap off the vapour finally has somewhere to go...on my 06 700 my vent hose was plugged with mud after fixing this i have never had another problem...some say its a problem with the check valve on the gas cap itself...a quick fix to that is to get a 660 gas cap...btw...i do have the problem fuel pump..but have had zero problems...
 

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R.I.P. Coop
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when taking off fuel cap...the gas seems to be "boiling" this is actually from pressurized air...when you take the cap off the vapour finally has somewhere to go...on my 06 700 my vent hose was plugged with mud after fixing this i have never had another problem...some say its a problem with the check valve on the gas cap itself...a quick fix to that is to get a 660 gas cap...btw...i do have the problem fuel pump..but have had zero problems...
Me too and when it was new, it did all that! Now... I have Zero, Nada, Zip issues!
 

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I got vapor lock on mine after a big mud hole on my 2nd ride. Man, was I pissed! Finally cracked the gas cap as a last ditch resort and she fired right up. I just took that long hose off the stock cap and put one of the $7 breathers from Rocky Mountain on and have had no issues since.
 

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Update, went riding last weekend and I had gas coming out of my breather cap on my gas cap. It was actually hot enough that my cooling fan turned on, lot of slow, climbing over obstacles trail riding. Lots of 1st & 2nd gear. It started hard on me once. Must have had some shitty gas, I was running 87 Shell gas, I use to run 93, but after doing more research, found there was no benefit on my stock compression motor.

Is it possible that higher octane would help prevent this or does the octane rating have no effect on the vaporization properties that seem to cause these problems.

Also, does Yamaha pay for the new fuel pump or would I have to if I have the bunk one?
 

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KUNG FU SAND PANDA
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Discussion Starter #7
Unless you have an extended service plan, I think that you might have to pay for it. You'll need to call your local Yamaha dealership to be sure.

Did you check to see if you have the newer fuel pump yet?

Also, I don't think that your cooling fan coming would have anything to do with the gas coming out of your breather cap. I would think that the cooling fan came on because you were climbing hills in low gears and since you didn't have enough air flowing over the radiator the engine got hot and thats what turned your fan on.

Maybe someone else could add to this and help you diagnose whats going on.

-Johnny
 

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I'm gonna call the stealership tonight if I get home in time to verify my model # on my fuel pump before they close. I bought mine used with the remainder of a 3 year extended service plan that the original owner bought for it.

I only mentioned the cooling fan coming on because this is only the 2nd time I can remember it coming on. The last time this happened it was an 85 degree day and 90% humidity.

I just wasn't sure if the gas has possibly contributed to this problem as well. Summer in WI means a ton of humidity when it warms up, no such thing as dry heat here, so I don't know how much the elements and gas choice for the day may or may not have contributed to my vapor lock & gas coming out of my breather hose the second half of the day.

I'll update tonight, plus my new rear brakes are supposed to be here too :thumb:
 

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This happened to me on 2 occasions in Spring of '07. Once at Martinez Mine and the other at Queen Valley in AZ. The problem is the temp here was tickling triple digits and the Winter gas blend was still being distributed. I always use 91 octane.
Once I read the service bulletin from Yamaha and saw the price of the new fuel pump, I decided to use a .8mm drill bit and increase the size of the vapor bleed hole. Haven't had issues since.

It was an uneasy feeling when it first happened since I was about 28 miles from my truck.
 

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I'm gonna check the model # tomorrow. Did the rear brakes tonight, took me 3 hrs, :wtf: :banghead:

FYI- If you do that, the piston goes in REAL easy when you remove the parking brake assy from the caliper, otherwise doesn't go in nearly far enough! :eyebrow:
 

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DAMMIT:banghead:, I have the 1S3-139707-01! We'll see if the Yamaha extended warranty covers this! Will keep you all updated!
 

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Dropped it off at the stealership today, claimed they never heard of the problem, but would check into it. I should have word early next week. Does anyone know if there is an link to an "official" document describing the problem? They didn't give me a hard time at all, just claimed :cunfuz:
 

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KUNG FU SAND PANDA
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Discussion Starter #13
The only thing that I have was the factory Yamaha service bullentin that I posted on page 1. Maybe print that off and bring it in with you or show them this site and my post.

-Johnny
 

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:thumb::thumb::thumb::rockon::rockon::rockon:

Got it back today, NO CHARGE, NEW FUEL PUMP, Yamaha covered it under the extended warranty that came with my used Raptor I got last year! According to the invoice, the fuel pump runs $387.23 + Labor. Thanks for posting this info up Johnny, helped me point the dealership in the right direction for a CORRECT diagnosis and fix :beerchug::beerchug::beerchug:
 

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This happened to me on 2 occasions in Spring of '07. Once at Martinez Mine and the other at Queen Valley in AZ. The problem is the temp here was tickling triple digits and the Winter gas blend was still being distributed. I always use 91 octane.
Once I read the service bulletin from Yamaha and saw the price of the new fuel pump, I decided to use a .8mm drill bit and increase the size of the vapor bleed hole. Haven't had issues since.

It was an uneasy feeling when it first happened since I was about 28 miles from my truck.
hey quick question. i have this problem on my bike, and i don't have extended warranty and dont feel like paying $400 for a new pump. is it easy to just drill out the vapor hole?
 

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MOMMA'S BOY
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if its the same part number as Johnny Baja posted then it "SHOULD" be covered LIFETIME if you havent replaced it yet
 

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Sorry for the old thread coming back up but should a 07 fuel pump work on an 06? I got that vapor lock.
 
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