Yamaha Intake Manifold and Throttle Body mount upgrades and why they are so important

[Green Hulk]

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I am installing the new billet throttle body mount and intake manifold upgrade on my GP1800 intake manifold and wanted to make a quick video to show you guys about the install and why these two mods are so important for us.

As explained in the video, the billet throttle body mount prevents boost leaks and the intake manifold upgrade (ribbon delete) improves performance. All Yamaha 1800 cc engines will use this same throttle body mount and all have a ribbon of which you will want to omit with the intake manifold upgrade.

These are the two parts I installed in the video

Deans Team Billet Throttle Body Mount for Yamaha 1.8L (2017 and older) Throttle body mount for the Yamaha 1.8L Waverunners uses billet aluminum construction, CNC machined, and is anodized red. Includes stainless steel... DT Billet TB Mount $85.00

or

RIVA YAMAHA 1.8L SHO/SVHO BILLET THROTTLE BODY ADAPTER / MOUNT (2017 and older) Replaces OEM throttle body adapter that is prone to failure and boost leaks. Includes all hardware, gaskets and O-rings for installation. Key...

RY13040-BTA

$85.00

RIVA Yamaha SVHO/SHO/HO Intake Manifold Upgrade Kit Our Intake Manifold Upgrade Kit enables your SHO engine to produce more horsepower by delivering increased air flow and boost pressure (+1lb)....

RY12040-IMUK

$39.95

https://youtu.be/k6g0iZvHnn0

[K447]

How to remove SVHO throttle body prior to ribbon removal, IMUK upgrade

I am learning more about working on the SVHO engine in the 2017 GP1800. I thought it might be useful to document the process I used to install these two items.

I found the provided paper documentation did not mention everything, hopefully these posts are helpful.

This is the throttle body, with the black OEM sandwich rubber dampener mount visible right below the intake manifold. It is held to the manifold with hex socket cap screws.

The throttle body is clamped to the OEM mount using long studs and nuts.

In my view it would be a near impossible fool's errand to try removing these pieces with the intake manifold installed on the engine. Difficult to access and impossible to see what you are doing.


There is a gear clamp holding the J shaped rubber intake hose onto the throttle body. Loosen that gear clamp until it is floppy. I forget the hex size of the socket. I used a deep 1/4" drive socket with a hand/palm drive spinner.


I found that it worked better to not loosen the other end where the flex J intake tube connects to the inter cooler.

There are also two support brackets attached to the bottom of the intake manifold. One on each side of the throttle body.

Remove the vertical bolt from underneath the end of each bracket. The bolt on the front bracket is very close to the rubber J tube. I used a flat wrench to work it loose, not really much room for even a 1/4" drive ratchet socket.

[Green Hulk]

Very good info Keith. Thanks for sharing!

[DaveMD13]

BUMP. I was emailing a shop last night, trying to set everything up for our first wave of upgrades and had asked him about this mod. Now I'm definitely sure I want to do it. I had figured it was good to do it because Gus had done it so early on his blue GP.

Good timing guys

[K447]

Before I removed the intake manifold bolts, the fuel rail and wire harness needs to be moved aside.

Note: Remove the lanyard and disconnect battery.

Note: Open the gas filler cap to release any trapped air pressure, then snug it closed again.

Note: Double check that the fuel feed has been properly reconnected and securely latched after all work is complete.



Multiple electrical connections must be disconnected, and several nylon zip ties cut or loosened. I may have forgotten about one or two in my description below.

There are two small connectors low at the front of the intake manifold, and another two small connectors near rear of fuel rail, thin wires from the top of the engine. Very little wire slack so it can be fiddly to get fingers on each connector and release the tiny latch.

Unplug the small black sensor above the rear end of intake manifold. The sensor itself is on a rubber mount attached to the manifold, the electrical connector release tab is quite small.

Follow the thick cable back from throttle body, unplug the connector at wire harness. There will be a zip tie holding the thick cable to the rear manifold support bracket. Cut the zip tie.

You may need to cut a few zip ties where the wire harness is tightly grouped just to the rear of the manifold. Keep track of what was zip tied to what.

Unplug all four ignition coils. I also unplugged the fuel injectors.

Tip: Count and make notes for each electrical connector you disconnect. If you forget even one connector during reassembly, the engine will not run properly.

The fuel supply must be disconnected from the fuel rail. Be sure to place a shop rag underneath the fuel connection. Slide the green clip upwards to release. It can be tricky to get the little ends to flex outwards just enough to allow the latch to move. Once it has moved about 1/4" upwards, the fuel hose and rubber mount can be wiggled towards the front of the hull.

There will be fuel spillage, be sure to catch it and mop up any drips. Leave a rag wrapped around the fuel rail end. I tucked the loose fuel hose end up and under the metal bracket below the glove box.

Remove the three bolts holding the fuel rail.

If you have disconnected enough things, the fuel rail can be wiggled away from fuel injector fittings, rotated upwards and then laid across the rear of the engine. I think it works better to leave the fuel injectors attached to the fuel rail, just be careful when tugging on the fuel rail that the injectors do not fall off.

[mikeFZR]

The fuel supply must be disconnected from the fuel rail. Be sure to place a shop rag underneath the fuel connection. Slide the green clip upwards to release. It can be tricky to get the little ends to flex outwards just enough to allow the latch to move. Once it has moved about 1/4" upwards, the fuel hose and rubber mount can be wiggled towards the front of the hull.

There will be fuel spillage, be sure to catch it and mop up any drips. Leave a rag wrapped around the fuel rail end. I tucked the loose fuel hose end up and under the metal bracket below the glove box.

Great write up. The fuel system will be pressurized (even if you loosen the gas cap) so fuel spraying when you remove the hose is common in my expierence. Like you said, best way to handle is when you disconnect, have a small rag wrapped around the fuel rail where it connects to the quick disconnect.

[K447]

There are two nuts and two bolts across the top of intake manifold. And another four bolts tucked below.

Remove all eight. Also remove the two vertical bolts holding the support brackets to the bottom of the manifold.

By now the hose clamp holding the rubber J tube to throttle body should also be loose. Fuel rail and wire harness moved aside.

Wiggle the manifold away from engine. Make sure the flat metal intake gasket is not stuck to the manifold, leave it in place on the two studs. Do not wrinkle or damage the thin metal.

Once free of the engine studs. Rotate the manifold left and right to work it up and out from the rubber J tube.

When you get the manifold out, the engine will look like this.



Note the two lower support brackets, and the thin metal intake manifold gasket.

The first engine I full removed the intake J tube (which is why it is not visible in this photo). On the next engine I left it fully attached to intercooler.

Move the removed manifold to a clean work space.

[K447]

Factory OEM throttle body configuration.





Following the IMUK instructions, remove the throttle body from manifold mount studs, then remove the OEM rubber dampener mount for throttle body.

The 'ribbon' flame arrestor disc I found difficult to remove without damaging it. Gentle prying and work the ribbon disc and rubber seal surround together, out of the manifold cavity.



I did not take step by step photos of the process

I cleaned the various bolt holes with a tap, cleaned the bolt threads, then applied blue Loctite to each bolt during assembly.

Install the tapered 'ribbon delete' sleeve into the OEM rubber seal. Make sure the arrow faces the correct direction.

Note: The rubber seal ring is also directional. The outer flanges are angled in one direction. Both must be oriented correctly.

I replaced the OEM (rubber sandwich with threaded studs) dampener mount with the red aftermarket throttle body mount. It came with four short cap head bolts, same as the OEM mount, so I just reused the short OEM bolts. Install the supplied green flat gasket.

Note the supplied aftermarket o-ring on the red adapter. The instructions mention re-using a factory o-ring, but I suspect that predates the current kit with flat green gasket and new o-ring.



The complete upgraded assembly looked like this.



Note the little metal tabs around the base of the throttle body intake sleeve. These are the stops that the rubber J tube must meet when the intake manifold is re-installed on the engine. Then the gear clamp will be tightened to keep the rubber tube in position.


Do not poke fingers at the throttle plate or try to rotate it.

Keep everything clean during assembly. I torqued each bolt in criss-cross pattern to torque specification.

[K447]

On the first engine I removed the rubber J tube from the intercooler, so this is what it would look like in position. In this photo the J tube is not fully seated onto the throttle body and the gear clamp is not tight.

You can see the wire ends of two sensors still attached to the manifold, plus the throttle body cable.



Note: On the 'front' end of the manifold is an anchored zip tie. To avoid cutting it (as I did not have a replacement on hand) I used a thin blade point to slip into the tiny toothed 'latch' and release the tie so it could slide back out.

Smear some water film or similar (instructions suggest using Windex) to the inside of the rubber tube and the outside of the throttle body, where they will fit together. Do not use oil or similar lubricant.

Wiggle the throttle body down into the rubber J tube, try to get it fully seated. I twisted the manifold back and forth while pressing the throttle body down into the rubber end. Only when I was sure the rubber tube was well seated did I align the manifold with the two studs and slide it against the engine.

When you are finished the throttle body and rubber tube join will look like this.



Note that the zip tie (to the lower manifold support) for the throttle body cable has not yet been re-installed.

Verify the metal gasket was not damaged or kinked, then reattach the intake manifold to the engine block. There are two studs to guide it into place. Put the nuts on finger tight, then thread each removed bolt into the correct hole. Blue Loctite was used on mine.

Do not torque any of the bolts until they are all threaded into place. Gently snug them all down before making any of them 'tight'. Follow the torque specs for these bolts.

Don't forget the two support bracket bolts, down under the manifold.

After the manifold is fully torqued down, tighten the rubber J tube gear clamp at the throttle body. Make sure the gear clamp is sitting squarely in the rubber groove, not canted at an angle. Use an inspection mirror or smartphone camera to verify it is correct.

[K447]

Engine fully re-assembled.

Note: I permanently removed the decorative black plastic shroud that normally covers the top of the engine, and I also removed the four metal support brackets for the shroud where they bolt to the engine. My primary reason was allow full visual inspection of the engine and provide better access around and below the engine. With the shroud in place it is harder to work around the engine. Taking it off and on gets old quickly.

Note: Lots of connectors. Check everything twice.

Make sure the fragile thin cables and connectors have been properly routed and zip tied.

Same with the heavy cable bundles. The factory zip ties were all there for a reason.

Keep in mind that the engine vibrates and shakes. Everything must be well secured, nothing loose or able to flop around.


Down at the front of the manifold are two small connectors. One has the factory zip tie routed through the connector to keep it in place.


The fuel hose connection to the fuel rail is critical. Take time to ensure the connector is fully seated on the fuel rail and then slide the green clip down to lock it.

The rubber U block must engage the two metal support tangs.


Wipe up all fuel drippings, including any fuel drops down inside the hull.

Discard the fuel soaked shop rag properly, it can be a fire danger.

[K447]

Check everything again. Especially the hard to see items.

Only when you are certain you have not forgotten anything, should you reconnect the battery.

Have a clean and dry shop rag on hand and a fire extinguisher. You had the fuel system apart, it might leak when the engine is started.

[CrazyA]

Look at you go Keith. Modding the 1800. Thumbs up!!!

[DaveMD13]

What a write up. He should have wrote the service manual. Ha ha

[K447]

... Thumbs up!!!

You could also click on the +1 icon

[Super Jim]

Check everything again. Especially the hard to see items.

Only when you are certain you have not forgotten anything, should you reconnect the battery.

Have a clean and dry shop rag on hand and a fire extinguisher. You had the fuel system apart, it might leak when the engine is started.

I know for sure it might leak! I had a 0-ring on one of the injectors pinched. I started it and looked at the manifold and saw gas spraying all over the the manifold! Check, double check, then look for leaks when you start it.