Engine Temp

[MASTER Brian]

I am needing to know an aproximate temp range for a 650 Kaw engine. It is an SBT engine and have not done anything to increase compression. It runs on pump gas. It does have a carb and pipe.
Thanks,
Brian

[Bryan Glynn]

Measured where? There's really only one temp that matters, an that's exhaust gas at the manifold. You need probes to measure that. Do you mean exit water temp or pipe surface temp?

[MASTER Brian]

I currently have a side exhaust and am wanting to add a rear exhaust, in order to create a dual exhaust system to my ski. I need a "y" and some tubing for this. I am wanting to make sure that whatever I decide to go with will be able to handle the exhaust temp. I have in the past used an aluminum tube, but have found a company that has some fiberglass tubing for boat exhausts and want to make sure the temp range on their tubes will handle my ski's exhaust.

Thanks,
Brina

[Bryan Glynn]

Well, the temps after your tuned pipe, assuming you are still running a stock wet exhaust, are I believe usually around 300-400 deg.

[Bill O'Neal]

I don't think it gets quite that hot because we used to install dual exhausts into the 550's using a kit that Mariner used to make. They supplied PVC tubing to use to run the exhaust through. The only time I ever saw one melt was when a guy was riding with no water supply to the motor or the pipe.

[MASTER Brian]

So, should I use PVC or Aluminum for a tube to go through the hull? Also, where can I find a "Y" or a "T" for a reasonable price for this mod. Everyone sells kits for dual exhaust running out the side of the ski, not out the rear(since newer ski's already have rear exhaust. I have asked several of the aftermarket companies, but have not had a reply yet. I think 24/7 has a fitting, but it is almost $70, which seems a little pricy for what it is.

[Bryan Glynn]

You can try PVC but it will probably shrink and may melt...you'll have to see.

[MASTER Brian]

Thanks for the help...Blowsion just emailed me and they have a "Y" made for this for a reasonable price and I will go with the aluminum for the tube going through the hull, I just hope it seals up as nicely as the last one I did.
Thanks again for all the help,
Brian

[Bud Man]

Brian, I'm curious.
Why would you want to put a dual exhaust in the jet ski?

It will retain a side exit and have also a rear exit???

Thanks and enjoy your set up.

[MASTER Brian]

The reason I am wanting to do this is to somewhat control the sound. The 550 hull has a side exhaust, which tends to be very noisy. I have a 650 engine with a limited pipe and I just added an aftermarket waterbox...all of these together adds more noise. Not only do I want to avoid being harrassed by the lake patrol, I do I want to add to the growing number of people that dislike jetski's. The rear exhaust should help muffle the noise level, by sending most of the exhaust into the water out the rear thereby muffling the sound. By retaining the side exhaust my engine will be better able to unload the exhaust gasses during tricks like a tail stand. The side exhaust is a mod that many freestyle riders use to help unload their ski's and if it is good for them, and they pay several hundered $$ to add this feature why would I want to eliminate it?
I was told recently after running the rear exhaust tube through the back of the ski that adding some water by-pass fittings to the exhaust outlet tube would also be a wise idea to help keep noise down. I plan on doing this also. I am just tired of people complaining and not being able to pull up next to my buddy on his ski and having to yell to comunicate.