Jeff jet 1750

[Allen M]

 

Na I haven't calculated belt speed, should be ok as I'm only turning it twice as fast as factory Honda cambelt...
Plenty other modified parts to worry about first...

Hmmmmmm!!!! It might only be turning at twice the speed as the Honda cam belt but the load turning the jet pump would have to be considerably more than what was required to turn the said camshaft. Still you don?t know what the limits of something are till you exceed them.

[Jimmy Jet]

I think the belt will be fine. Only basing my assumptions on a Harley Davidson belt drive and the torque transmitted in that application. I think you have a bigger proportion of belt area.

[Jeff B]

Basing engineering strength on Harley Davidson equipment is not what I call hi tech....
Not sure really? Camshafts are pretty tough to turn...2 of them...I'm not sure how much torque they absorb??
Anyway....I could spend a day researching and wondering about it or I can just run it and upgrade to something else when/if it fails....
Destructive testing is much more gun....

[Ross Goldsack - JBNZ Immediate Past President]

I'd be more worried about the dentistry bills after it shakes your teeth out

[Jeff B]

Few mods to engine.
Had to bodge up the water feed Inlet, raw water of course.

[Jeff B]

Assembled top end.
Man the ports are huge! Not much cylinder left with all those holes through it....

[Jeff B]

Fitted pulse line fitting for fuel pump
Hopefully pressure is low enough I dont need header tank.

[Jeff B]

I still need to figure out how to actuate the power valves too...
Maybe another lever or button on steering wheel?
Raises the exhaust port a good 6mm so definitely needs it for power.
Not sure it will idle with them fully open?

[Jeff B]

Finished off the exhaust, managed to tuck the std muffler up under transom with a little silicone water trap on end.
Just gunna wrap copper pipe around the header to pre heat raw water before entering cylinder. Not sure how many wraps I'll need? Will just heat wrap the whole exhaust system (rangi I know)

[Jeff B]

Electrical system installed and hooked up, easiest electric setup yet..a coil and CDI....
Fired the wee stinker up,
Pulse fuel pump is providing too much pressure and flooding carb, needle valve and seat are pretty big, 2.2mm (for gravity feed from tank) might try a smaller needle and seat before rigging up a header tank??
Vibrates a bit...less than the 300 though....

[Tones]

Jeff, Gates make a carbon fibre belt that would be ideal in that drive application. I have used them on forestry equipment and have worked well. The downside is they have to be perfectly alined which shouldn't be a problem for a genius Gates Polychain Belt.

[Jeff B]

Jeff, Gates make a carbon fibre belt that would be ideal in that drive application. I have used them on forestry equipment and have worked well. The downside is they have to be perfectly alined which shouldn't be a problem for a genius Gates Polychain Belt.

Yeah my local sponsor bearing supplier showed me the carbon timing belts, same thing. He said they were quite expensive? Not sure what his interpretation of expensive is.....jet boating has somewhat numbed my cost scale....

[Tones]

The belt I had was rated to 5000nm torque, cost $1000

[Paul]

The belt I had was rated to 5000nm torque, cost $1000

How can a belt be rated for a torque?  Surely, that depends totally how many teeth are engaged on the pulleys and the diameter of the pulleys..

[Warwick Marflitt]

Finished off the exhaust, managed to tuck the std muffler up under transom with a little silicone water trap on end.
Just gunna wrap copper pipe around the header to pre heat raw water before entering cylinder. Not sure how many wraps I'll need? Will just heat wrap the whole exhaust system (rangi I know)

Rangi Jeff!
      Now there's an Oxymoron if. ever Ive heard one.....it'll be fine mate....
I'm wishing I'd  ma cake hole bout the cam belts service rating... Your on the right verdict though S.I.A.S "suck it and see"? Thinking about your set up... You only have 33hp and that'll only make X amount of torque. So wither it gets to 11,000rpm or not. The pump will resist against only what the engine puts out.... so it's kinda a self full fooling prophetic equation? Limited by the engine more than the unit. Unless the Impellers are too steep. But that wont cause belt failure.... Any hoot it gave us all something to bleat and yap on about..... Your a legend Jeff