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I miss the old news groups, Grabowski was constantly defending his honor.

Three seconds to hit the pipe is usually too much pump. If it were the carb, opening or closing the top screws will affect the spool up time. Carb tuning is easy once you bore the nozzle and flatten the impeller. The bottom screw is for idle only! Set it on the trailer, close it until the idle...

Whatever you do, stay away from aviation!!!

There is big profits in custom carbs. People don't know much about venturi sizing so making them bigger is an easy sell.

Is your tank vented? If not then warm gas will effectively lower your popoff due to increased vapor pressure. This does show up with low popoff pressure. I would shorten the duration of 1/4 throttle holds for tuning. The ideal pilot will tend to be very rich after a few seconds.

The mixture requirement is much richer whenever the pipe is working. Power falls off very rapidly when the RPM exceeds the pipes resonance mostly because of the air/fuel mixture becoming overly rich for the conditions. The slightest reduction in torque is where the RPM will stall since the...

Im sure that it will rev higher with a taller port and/or shorter tuned length, my porting was 120/182. Once you get the pump load light enough for good response the pipe will go rich and wont rev much more. Small CC engines struggle getting on the pipe with much more than a 9-15. A...

My 701 with 182 degrees open exhaust will not rev over 7000. Low end was soggy when propped at 6800. I flattened out the impeller for good response and it turned just under 7K. Top speed was the same in smooth water. The pipe works well with low ports.

Usually, maximum low speed pull will be a mixture rich of peak rpm unless you are trying to use big pilots and small mains. You need glass smooth water to fine tune the main circuit at full throttle. For freestyle just tune for best response and max pull.

It is mainly about fuel draw. Individual inlets get a stronger signal than a shared manifold. A pair of 44s hit the pipe at 40% throttle while the single required 60% and didn't pull as hard. A larger single was about the same as the twin 44s but with the high speed lean out. I made sure...

The full throttle lean out is something I figured out the hard way. I could install a big main and open up the top screw enough to sustain full throttle. By then it would stumble on spool up. If I cleaned up the main it would get too lean at full throttle, I could hear the detonation buzz a...

A single 46 or larger is fine for throttle blipping, they tend to go lean and stick pistons on full throttle runs. A 44 on 61x cases tunes well and is safe for holding full throttle. For better response and ease of tuning get a pair of standard SBN44s for your 62t Case. Its the best combo...

Everything has been tried in the past when there was a lot more money flowing into the sport. The 1995 WF winner had custom twin pipes in his 750sx. The current freestyle boats can barely house a single pipe, and most importantly, riders aren't asking for twin pipes. For a freeride standup, I...

Another problem I often see is splines wearing after an impeller change. People don't realize that sand collects in the tunnel and gets on the splines when reassembed. A little sand increases the wear factor many times over. The stub shaft must also be removed so that the tunnel can be cleaned...

You will need a complete couch engine, a good pipe, and a good impeller. That should outrun that SXR unless he also has a good pipe .

Tune the main circuit with a tach in smooth water. If your pilot/popoff is close to stock, you will lose throttle response before the main circuit is leaned to peak rpm. Adding larger pilot jet and/or lowering popoff will make it sputter a lot at 1/4-1/2 throttle but will allow good response...

A little hook on the side is only way for a ski to hold an edge at high speeds. You have to slow down a lot before cornering without it. Its not very useful at low speeds like in the old slalom race. The 750 was the fastest turning flat sided ski, the SJ was easier to ride for 10 long laps.

Go as low as you can unless you are racing. No greater than 15 degrees for a pump gas 650.

Find a Kawasaki head pipe or make a 1" spacer ring for the chamber. These mods will make the pipe come on a little sooner but also reduce power. The real answer is a bored nozzle and lower pitched impeller.

Watercraft engines can stick pistons faster than anything. Do application specific research, there is plenty of knowledge of every type. Retard the timing if you are tuning for long full throttle runs. You usually end up finding the meltdown point.