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Superjets didn't catch on and do well in racing until 1994 when slalom was removed. At the time we were most interested in going fast and jumping wakes. We thought the 750 s were better at the time. I eventually got the power out of the Yamaha and never looked back.

I remember when Superjets couldn't beat a decent 550 anywhere.

The Yamaha pump has a little more capacity than the smaller Kawasaki unit. It allows more inlet area and lower pitch impellers for a given power. I installed a Yamaha pump in my x2. The performance difference was in hookup and holeshot.

I would not use the cone that comes with the Solas pump. Use any small hub cone or get a short large hub cone. Jazz was selling them for $40 as Polaris cones.

Twostrokes need a coarser grit than fourstrokes. Typically around 220 for iron cylinders.

I think they were all 650 pipes. They run good but are a little short for best response.

Last time I looked, the 62T cut manifold needed to be mounted higher than center in order to get even gasket engagement.

You are at the point where getting more requires all the goodies and higher ports. A 760 bottom end will make the pipe hit sooner and harder, but not all that much. A T/L will make the throttle very crisp. Doing both will make a nice improvement but it won't go any faster without raising the...

You may want to check the running temp of your waterbox. It could be getting over 200F, adding a .125 stream will keep it under around 150 at full power.

The easiest way to keep water out of the exhaust and raise its temp is to use a large pisser in the outlet line and install an 1/8" restriction at the stinger.

Set the bottom adjuster on the trailer at idle. Just close it until the engine revs up then open just enough to slow it back down, the mixture will be very near perfect. The screw can end up anywhere from 1/2 to 2 turns out depending on popoff pressure.

The big hub will stay connected noticeably better. Your high port engine will not tolerate any overloaded condition so be prepared to use a bored nozzle and bend the back edges of the prop if you get sluggish response. Cones make no difference.

The headpipe is sealed from the manifold by the gasket. Water is generally routed the same as the Kawasaki 650s. I would make the rear bung the water outlet since the cooling port is drilled there. This will help clear out any debris.

If the mixture is tuned for best power at 90-100F, any temp lower raises combustion temps. Cooler water plays a part although much smaller. I run more piston clearance these days along with the carb set a few rpm rich of peak power. This allows for a lot of abuse without sticking a piston.

It is the hotter combustion temps caused by a cold intake tract that stick pistons. Cooling water runs through a light weight aluminum exhaust manifold that heats up in a few seconds. What do you think makes a bigger difference, combustion temps 200 higher or water 40 cooler?

This engine used a stock 61x bottom with a 61x cyl ported almost to 62t timing. The pipe was a sizzler and the pump was set for 6900 min. I never could get it to rev over 7k. It had fair response and ran 48 all day. I later exchanged this lower for a complete 760 case/carb. It made the pipe...

Dropping the pop off will make the pilot jet and idle screw much richer. I found a 130 to be too rich with 2.0/80g, it did allow for a peaked out WOT without hesitation. A 125-2.0/95g is probably about right but try an 80g and note the difference. Changing the pop off won't change full throttle...

How do you know the proper temps? Some engines run great at 1100, others melt at 1000. These instruments are not widely used in watercraft anyway. An experienced ear and cheap tach will allow you to find best power quickly and safely. Exhaust temp and plug color are secondary to the fact that...

Pilot jets are always very sensitive, going from a 120 to 125 is very noticeable. Single carb setups make the main circuit insensitive to small changes, you need to make larger moves. My last 61x cased 701 needed a 160 and 2 turns in order to get 20 rpm rich of peak.

Egt tuning is no good unless you already know what they should be. Best power mixture occurs below max temp. We have the ability to measure power with a tach, the temps don't matter.