Tech Info


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This issue has been reported on two Yamaha TR-1 engines with 130hours of operation including their regular periodic maintenance service. The bolt in the oil pump gear is losing its tightness and the gear driving the oil pump falls out and causes damage to the engine. We have our (Networx Jetsports, Philippines) second incident just now. If anyone has experienced a similar issue please share your opinion.

The new SX-R features a big drain opening (under the drive line bearing housing) between the engine compartment and the rear (under the tray) part of the ski. Therefore, if water comes in while riding or when you wash off the engine with tap water it can be drained fairly quickly. However, when you do the periodic maintenance make sure you put a piece of foam in the opening so if you drop anything (for example a 10mm socket, a small bolt, etc) it will not end up inside the rear end…

According to the Japanese engineers that were present at the European press launch of the new Yamaha WaveRunner the all new EX is equipped with a new pump of 143,8mm in diameter. The impeller is also new with 12,1/14,1 pitch specifically tuned for the new watercraft. The spec was supplied to Jetskiworld.gr through Jet-Porda in Germany and the photo was sent from Kommander Industries.

The Rhaas aftermarket engine mounts that are illustrated were used on a Sea-Doo with a stock engine set up for Pro Stock class. The initial height of each engine mount was 8mm however after the use of approximately 40 hours the height was lowered to 4mm at the sides (and not radialy from the center). Has anyone experienced a similar issue? Due to the warranty the company offered t the customer a brand new set of engine mounts.

The dimples have two purposes in my opinion. 1.) The dimples promote better mixing of the fuel/air mixture. This promptsore complete combustion. 2.) Like the surface of a golf ball the dimples will thin the naturally occurring aor boundary layer between the port walls and the transient (not laminar) air flow. The thinner boundary layer effectively enlarges the port increasing its flow potential.I wonder how the builder was able to machine such a symmetric pattern within the port...

Lateral Gas Ports are horizontal slots in the top of the top ring groove and they provide a passage for combustion pressure to get behind and above a top ring, increasing ring seal with reduced radial rings. Photo courtesy: CP-Carillo

How can it happen? It is possible? Well, the photo says it all. Possibly the illustrated battery was charged without enough battery fluid in it and then when the electric current went through, it shorted. That is a possible explanation unless someone else has a more appropriate approach. Photo courtesy: Networx Jetsports

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