New jj2250

[Jeff B]

Building a little pocket rocket. This is the first 2250 with recessed plastic bottom.
6mm bottom, 12mm plastic, 4mm outers/bow, 2.5mm sides.
13 deg
Solid strakes.

[Jeff B]

144mm yamaha pump.

[Jeff B]

Bottom.

[Jimmy Jet]

Cool. What driveline in this one Jeff?

[Jeff B]

This one is getting little 2 cylinder Uamaha 66e , GP800. Powerful little engine but the factory expansion chamber is huge and curls around front of engine, take up too much space, and Is heavy.
Big job but I'm building twin jacketed pipes for it, tacked up the inner before sides went on so easier to work on.

[Jeff B]

Fully weld up the inners then tack the jackets over outside. 2.5mm inner, 2.5mm outer.

[Jeff B]

Exhaust pipes taking up a bit of time,  built fuel tank, handy for mounting electrical box, battery, power valve motor, fuel filter etc, and it's my seat too.

[Jeff B]

Finished chambers off. 33mm stinger, good for 70hp (per cylinder) apparently...
Plumbed up to original water box, hopefully not too loud.

[tyro]

that exhaust setup is truly a fabrication work of art

[Jeff B]

Yeah the exact is one of those jobs where if you knew how long it would take, wouldn't have started it haha. Had to get a bit creative with the chamber water outlet so it all sits below engine cover. Just waiting on some hose barbs and it can be all plumbed up.

[Jeff B]

All the  ig components in. Just gotta hook up dash, wiring now. Pretty simple with ski gear.
The principal of basic, simple 2 stroke install seems to have eluded me on this build, pretty complicated setup but I have made it easy to access the common culprits, spark plugs and carburettors

[Jeff B]

Got some decent rubber mounts, the generic "lord mounts" don't seem to last long before Falling apart.
These are automotive spec, actually transfer box mounts for a Mazda Bongo van...common and pretty cheap at $25

[Jeff B]

Some grunty springs to hold exhaust O ring seal onto cylinders. Motorcycle spec here.. 

[Jeff B]

Thumb throttle.
This is a modified quad bike thumb throttle assembly, the cable goes down centre of steering  shaft. Makes tidy and no cable to get snagged on sticks.

[Keltik]

Ready for next weekend?