Jeff jet 2.0

[Jeff B]

Little project I have been chipping away at in between other jobs.
2m long
[email protected] chine.
5mm bottom, 3mm outers, 2.5mm sides.
13 deg

[Jeff B]

Aim was to make easily handled, lightweight but still pretty tough and safe and reliable.

[Jeff B]

In pursuit of the lightest engine setup decided to run with single cylinder kawasaki. This is only 22kg ready to run. About 30hp.
The factory exhaust ran too far forward and not easily modified and heavy cast aluminum.
So I made a new race chamber out of 0.9mm stainless, first 400mm is jacked

[Jeff B]

The std 300/440 pump is a piece of crap and needs shimming to set up tolerances so I have used a modified 550 pump with new custom solid stainless wear ring on 7.5 deg taper. Shim impeller forward to decrease OD wear.
Made a lightweight reverse bucket that hardly works but better than nothing

[Jeff B]

Heavy duty bizalloy 400 grill.
Trying to keep light but most strong components are heavy....

[Jeff B]

Made proper fuel tank that acts as seat base, 25 litres.

[Jeff B]

Made proper steering, chain, rope, pullies, bellcrank. Works well, tiny tech and 2x buttons go and stop.

[Jeff B]

https://youtu.be/v082Ax2aQFY

[Jeff B]

Performance is surprisingly good considering I have about 33hp on tap
The engine goes well but only downside is it vibrates quite a lot at idle, between idle and 4500rpm, and above 6000rpm...
Has a real nice sweet spot between 5000 and 6000rpm. About as smooth as any multi cylinder 2 stroke ski engine (still not very smooth)
Pops on plane relatively fast. Minimum plane about 4000rpm
Cruises nicely about 5000-5500rpm and WOT 6250rpm.
Cruise happily at 40km/hour and tapped out, full noise 52.5km/hour.
Carrie's 2 adults easy buy does take a bit to get on step.

[Jimmy Jet]

Cool. Why not put some pad-eyes and straps on so you can wear it like a back pack?!
Haha. Whats the Kawi 300 out of? Not a dirt bike I'm sure?

[Jeff B]

It's a jet ski engine. Straight from the 1980's with some super duper performance enhancing modifications

[mohawk]

Yup , smooth as a concrete mixer full of sledge hammers 

[Clint640]

Awesomely ridiculous 

I reckon you need to build a catapult launcher for the back of the Hilux so you can just back up to any likely bit of water & fire yourself off like a jet from an aircraft carrier 

Cheers
Clint

[Jeff B]

I use an old ladder as a ramp and I have an electric winch in the back of the Hilux that I drag it up with. Works well. No trailer needed.
2 strong guys can lift it but it's a bit awkward and Mohawk is pretty weak...

[Jeff B]

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