Super Jet Exhaust leak...or? Ski runs like crap with hood on.

[yamanube]

Lol I doubt it maybe a critter is nesting in ur hood lol

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I have tried 4 different hoods, one being stock.

Check your fuel tank fill for loose connections. I've seen a fill tube come partially dislodged and have similar symptoms to an exhaust leak.

The stock fill is capped and it has an internal fill mod which is air tight. The gas tank seems to function exactly as it should with the check valve being good and no weird air leaks.

 

[Lm12]

What I'm saying is check the vent tube that runs through the rubber collar up into your handle pole. Could easily be getting crimped or pinched as the pole moves.

 

[yamanube]

It does not go up my handpole like the stock setup, my vent runs into a check valve then is just a short section of hose looped once and sitting on the tank. It is definitely not crimped or pinched or plugged.

 

[Lm12]

Ah 10-4. Run it on a hose and see if you notice water on your starter. Possibly have a leaking exhaust manifold that is allowing water to go into the cylinder.

 

[yamanube]

Ah 10-4. Run it on a hose and see if you notice water on your starter. Possibly have a leaking exhaust manifold that is allowing water to go into the cylinder.

Plugs don't look like they have gotten wet, no water on starter.

 

[Coreyf983]

have you checked you dont have a loose baffle, we were just chasing the same problem on a buddies ski and it ended up being a loose baffle

What baffle are you referring to?

Jason, this is very similar to what I have going on. Check your exhaust hoses for bulging. I think there are two layers to your exhaust hose and a bubble may develop in between the two. As it gets warmer, this bubble will grow and can pinch off your exhaust exit. Maybe the problems went away because the temp in the hood is lower without the hood on? This is far fetched, but just an idea.

 

[Coreyf983]

I run 32:1 dino oil, my exhaust is smokey and sludgey and still can't find anything.

Just curious, why so rich?

 

[yamanube]

What baffle are you referring to?

Jason, this is very similar to what I have going on. Check your exhaust hoses for bulging. I think there are two layers to your exhaust hose and a bubble may develop in between the two. As it gets warmer, this bubble will grow and can pinch off your exhaust exit. Maybe the problems went away because the temp in the hood is lower without the hood on? This is far fetched, but just an idea.

Yeah checked for that, I have seen that happen as well, my tubing all looked (and felt) fine. It's possible I missed it but not likely.

 

[Coreyf983]

What baffle is he referring to?

 

[Big Air Mike]

I have been fighting issues on my ski for some time, it had developed a real bad bog that I couldn't seem to get rid of. It seemed to be fine when first put in the water then get worse as the day went on. I attributed it to bad electrical components (heat soaking and getting progressively worse) and replaced the stator and then coil but the issue continued. Finally got a chance to ride some flatwater this weekend and ran the ski less hood (figured maybe it wasn't getting enough air through the XMetal hood). Sure enough it cleared my issue right up. Tried a couple different hoods to see if maybe mine just wasn't breathing well enough but as soon as I put a lid on it it ran like poo. I have looked over all my exhaust hoses all clamps are tight, all hoses look to be intact. Normally a leak will show up with black exhaust sludge. All the joints are clean and dry.
I plan on getting out a spray bottle with soapy water and just going over everything but from what I have seen so far everything looks fine. Anybody have any other pointers to find my gremlin?

Hey Yamanube, did you ever solve this issue you were having? I resently purchased a NOS XFT hood and am now having similar issues with my superjet as described in this thread. Thanks in advance for your feedback. Running stock air box, hood has no breather tubes attached, basic mods to engine (JetManiac cylinders/top end, bpipe, head 35cc domes, .....)

 

[ajmccracken]

What baffle are you referring to?

Jason, this is very similar to what I have going on. Check your exhaust hoses for bulging. I think there are two layers to your exhaust hose and a bubble may develop in between the two. As it gets warmer, this bubble will grow and can pinch off your exhaust exit. Maybe the problems went away because the temp in the hood is lower without the hood on? This is far fetched, but just an idea.

I think this is what happened here. Waterbox also got extremely hot and melted the turf i put on it. B pipe temp only went up a little.

 

[ajmccracken]

I think this is what happened here. Waterbox also got extremely hot and melted the turf i put on it. B pipe temp only went up a little.

Bpipe couplers are completely fine. No discoloration on chamber. Im trying to figure out if the baffles got stuck. But yeah that hose has some massive bubbles.

 

[kevbo]

I think this is what happened here. Waterbox also got extremely hot and melted the turf i put on it. B pipe temp only went up a little.

You gotta put some water in the exhaust! The ringing in your ears is a dead giveaway.

 

[ajmccracken]

You gotta put some water in the exhaust! The ringing in your ears is a dead giveaway.

It had plenty of water but i couldnt blow it out. Im still chasing down the original issue. All lines are clear, engine temp and bpipe temps are good. Im thinking baffles but cant get the waterbox open to check.

 

[ajmccracken]

Shake the Waterbox like a Piggy Bank and see if it Rattles....

I tried that, just heard water. I'll take a hammer to it tonight. It's the original fiberglass one and I'm replacing it anyway.

 

[ajmccracken]

The OEM 650 Fiberglass WaterBox?

Don't smash it. Saw cut it open. Or just Hole Saw an Inspection Port. Then you can Epoxy it back together. If you do, I'll give you the Ancient Chinese Secret to using Regular Temp Epoxy Resin for Hot Temp Service.

Before you cut/drill it open, check to see that the Rivets are not leaking Air into the Waterbox. Stick a Pin down each Rivet. If the Pin goes thru, then the Waterbox is leaking.

Leaking Rivets are , in my opinion, the reason why these Fiberglass Waterboxes eventually explode

The Blind Rivets have a Center Part called the Mandrel. That's that piece that looks like a Nail that you pull on with the Tool to crimp the Rivet in place.

View attachment 426913

I can confirm they are leaking. There is black sludge all down the sides of them. When its running, you can see stuff coming out of them.

 

[ajmccracken]

Well, then you haven't lived till you had a Yamaha Fiberglass Waterbox explode next to your Ear

That's part of your problem then, Waterbox is losing Water Vapor thru the leaks and also drawing Air into the WaterBox, then the Pipe and back into the Cylinder making them run lean and overheating.

To fix the Rivets, simply plug/View attachment 426915cap each one with JB Weld High Temp Putty like this:

View attachment 426914

Let me know if the Waterbox seams are leaking and I'll give the Repair Hack, I mean Procedure

Seems are all good. Ive got a raddudes one on the way. Ive heard of these exploding and want no part of that lol.