Where/how to check Yamaha SVHO J-Tube (J-Pipe) at Throttle body

[badjoka]

. I also added a tapered 1" rubber stopper via zip tie to the lowest point of the J-tube to provide back pressure against the hull to deter blow-off.

Simple and smart!

[randynixon74]

Update... the gap between the J-tube and throttle body was the source of my missing top-end power. Finally got out for a test run yesterday morning and knew as soon as I reached 1/4 throttle that the power had returned. This was also my first ride with tachometer and boost gauges installed. RPMs north of 8250 and boost of 10-12 psi tells me the ski is back to Stage 1 performance. If you're struggling with the factory J-tube staying put, this fix works well. I'll monitor for the rest of the summer and report back if there's any change. Thanks for the great tips on this sticky.

[randynixon74]

Decided to swap the OEM gear style hose clamp with a Spectre Pro Performance 8703 T-bolt style clamp (3") between the throttle body and lower end of J-tube. I've had the J-tube pop off several times while trying to troubleshoot a boost leak. I also added a tapered 1" rubber stopper via zip tie to the lowest point of the J-tube to provide back pressure against the hull to deter blow-off. Fastening the T-bolt clamp off the ski allowed me to really torque it down, then rock the manifold into place and tighten the OEM clamp to the intercooler. Now, onto the supercharger...

,

[K447]

- very difficult to get at it and get both sides on. The location to get at it is very tight.

I'd love to hear any tips or tricks to make getting this on easier.

Do not use any form of petroleum, oily or silicone lubricant. Once in place you do not want it to slide off again later while riding.

You can spray regular window cleaner inside the rubber end just before sliding it onto the throttle body. The wet surface provides some reduction in friction and will evaporate later.

My arm and hand is just narrow enough to work down there but it certainly is not easy to get the J-tube onto the throttle body and then ensure it is fully seated. If you can reach below the J-tube you might be able to pull upwards on the bottom bend to help shove it onto the throttle body.

For those with bulky arm/hand, perhaps ask a friend with thinner arms to help reseat the thing and clamp it snug.

Use an inspection mirror and flashlight to confirm correct positioning. If your mobile phone will fit down there, turn on the camera light and take some photos to show you where things are located. Hang a shop work lamp (LED) down behind/beside the engine on the right side so you have some light to work by.

It is easy to end up with the metal band clamp angled and not properly aligned with the molded slot in the J-tube rubber end. Make sure the band is seated in the slot all the way around and recheck periodically as you tighten the clamp.

A compact 1/4” drive palm style spinner tool with the correct socket size can be easier to use than a regular 1/4 ratchet handle tool in the confined space around the throttle body.



http://greenhulk.net/showthread.php?t=270305&p=2941375&viewfull=1#post2 941375

http://greenhulk.net/showthread.php?t=260795&p=2885694&viewfull=1#post2 885694

[sam101814]

Great post @k447. I had this “J pipe” pop off at 85 MPH (not a fun experience). I also had thought it was the supercharger clutch. It was in fact the J-pipe that popped off of the intake manifold.

I will say it is tight to get at this area in the Hull, and takes some finessing to get at it.

RS is right...was very difficult to get at it and get both sides on. The location to get at it is very tight. I'd love to hear any tips or tricks to make getting this on easier.

[K7fxho]

Thinking of changing this to a T-bolt style clamp like I used on turbo cars

[R S]

Great post @k447. I had this “J pipe” pop off at 85 MPH (not a fun experience). I also had thought it was the supercharger clutch. It was in fact the J-pipe that popped off of the intake manifold.

I will say it is tight to get at this area in the Hull, and takes some finessing to get at it.

[Dust N' U]

SHO or SVHO engine?

2015 SVHO

[Dust N' U]

We had it come off at the intercooler on the FZR.

[Reaper9789]

Always good info!
We have had plenty come loose.

[chudiddy]

Moved this post to a separate thread to make it easier to find.

Original thread is here

http://greenhulk.net/showthread.php?t=291703&p=3118634&viewfull=1#post3118634

Related thread discussing where the J-Tube is located.
http://greenhulk.net/showthre...=1#post3167419

Wish i found this before I changed the clutch. LOL. Oh well!

Thanks for posting this.

[K447]

Moved this post to a separate thread to make it easier to find.

Original thread is here

http://greenhulk.net/showthread.php?t=291703&p=3118634&viewfull=1#post3118634

Related thread discussing where the J-Tube is located.

http://greenhulk.net/showthread.php?t=284841&p=3167419&viewfull=1#post3167419

[K447]

... I bought the unit used with 50 hours. ...

With any new-to-you watercraft, always a good idea to check every single hose clamp throughout the hull.

Including the J pipe between intercooler and throttle body

Even factory new, but especially when you do not know the service history or what might have been touched.