Harley powered twin jet drive problem

I'll clean up the shaft, and order new bushings....see how that goes.
The other problem with this is it's a Harley.... straight piped.... awful noisy... I wish the guy would of used a Honda Goldwing motor or something close. I'm going to check with custom pipe manufacture for new pipes and a set of mufflers... I am also curious about dumping exhaust in to water?
If a guy had to repower this.... with low noise in mind any suggestions?

 

Was there any engineering effort behind this build?
Harley motors are renowned “bone shakers”, would not be my first choice for a boat motor by a long shot.
Jet ski motors are state of the art power for jets, I’d be looking along those lines.

 

I'm not sure why builder decided on Harley....no idea.... maybe he had one laying around ... who knows what's in the mind of eccentric craftsmen...
Talking jet ski motors.... with the twin jets.... do the power those with 1 motor?

 

One motor per pump, the name of the game is getting the power to the pump with minimal losses along the way.

 

Yamaha jetskis are probably the most popular (there are certainly a lot of them here).
The original ones had fairly small (I think 600 or 750 cc) 2 stroke engines, but later ones have 1050 cc 3 cylinder and 1100 cc 4 cylinder 4 stroke engines.
I have seen a couple of Yamahas here with 1800 cc 4 stroke engines in them.....

 

In the automotive world they refer to shade tree mechanics, clearly they have marine brethren.

 

Sea-doo PWC's can have powerful Rotax engines with a supercharger as standard. It's a compact lightweight unit; some Seadoos had twin engines and jets.