"JAXAshby" wrote in message
...
One thing you have to deal with is thrust from the propellor and shaft.
Car and motorcycle engines and transmissions don't have thrust bearings
as in a marine transmission.

They sure do. If they didn't, they wouldn't last very long.

What utter rubbish!
There are motorcycles out there that will withstand thrust directly down
the output shaft?
Frankly i dont belive you.
even shaft driven bikes tranfer thier power through turning motion only the
shaft is only subected to torque. not thrust.

A boat prop Pushes the shaft forwards... which via the gearbox
bearings......pushes the engine... which takes the boat forwards with it cos
its bolted to the boat!
Its one of the reasons that boat engine mounts are a tad more costly than
engine mounts for almost any other use.
Select reverse.. (not a lot of bikes have reverse... a few.. but not many)
and the shaft pulls .. I'd guess that would be very sudden death for most
non marine gearboxes.

It appears you don't have a clew what a thrust bearing is.

From: "James"
Date: 2/8/2005 9:03 A.M. Eastern Standard Time
Message-id:


"JAXAshby" wrote in message
...
One thing you have to deal with is thrust from the propellor and shaft.
Car and motorcycle engines and transmissions don't have thrust bearings
as in a marine transmission.

They sure do. If they didn't, they wouldn't last very long.

What utter rubbish!
There are motorcycles out there that will withstand thrust directly down
the output shaft?
Frankly i dont belive you.
even shaft driven bikes tranfer thier power through turning motion only the
shaft is only subected to torque. not thrust.

A boat prop Pushes the shaft forwards... which via the gearbox
bearings......pushes the engine... which takes the boat forwards with it cos
its bolted to the boat!
Its one of the reasons that boat engine mounts are a tad more costly than
engine mounts for almost any other use.
Select reverse.. (not a lot of bikes have reverse... a few.. but not many)
and the shaft pulls .. I'd guess that would be very sudden death for most
non marine gearboxes.

JAX says:

It appears you don't have a clew what a thrust bearing is.

At least he knows how to spell "clue" ;-)
The thrust bearingin a shaft-drive mo'cycle engine does NOT take care of thrust
in line with the shaft.

Steve "go for it, Jax, you know you want to...."

It's cheap, it's easy - go for it. If it lasts two weeks, then so be
it, but at least we'll have some form of quantitative data on the topic
in this newsgroup.

You could build a free standing bearing structure which the prop shaft
bears against (laterally) and couple it to the motor - maybe with a
flexible drive. Or a similar arrangement with the chain drive
preserved (covered of course). There's always the pump route - but not
exactly cheap if you have to go with new parts.

Oops - also the issue of spark proofing the various electrical bits,
and the flame arrestor on the carb. Not sure what you would do about
those - could just leaving the whole thing in the open for the time
being.

all engines have a a thrust bearing, except any engine owned "James" (who will
be googleing for the next 24 hours trying to figure out how he could be so
ignorant).

From: "James"
Date: 2/8/2005 9:03 A.M. Eastern Standard Time
Message-id:


"JAXAshby" wrote in message
...
One thing you have to deal with is thrust from the propellor and shaft.
Car and motorcycle engines and transmissions don't have thrust bearings
as in a marine transmission.

They sure do. If they didn't, they wouldn't last very long.

What utter rubbish!
There are motorcycles out there that will withstand thrust directly down
the output shaft?
Frankly i dont belive you.
even shaft driven bikes tranfer thier power through turning motion only the
shaft is only subected to torque. not thrust.

A boat prop Pushes the shaft forwards... which via the gearbox
bearings......pushes the engine... which takes the boat forwards with it cos
its bolted to the boat!
Its one of the reasons that boat engine mounts are a tad more costly than
engine mounts for almost any other use.
Select reverse.. (not a lot of bikes have reverse... a few.. but not many)
and the shaft pulls .. I'd guess that would be very sudden death for most
non marine gearboxes.

On 08 Feb 2005 14:29:20 GMT, (JAXAshby) wrote:

Posts like this are helpful in knowing whose posts to ignore'

all engines have a a thrust bearing, except any engine owned "James" (who will
be googleing for the next 24 hours trying to figure out how he could be so
ignorant).

From: "James"
Date: 2/8/2005 9:03 A.M. Eastern Standard Time
Message-id:


"JAXAshby" wrote in message
...
One thing you have to deal with is thrust from the propellor and shaft.
Car and motorcycle engines and transmissions don't have thrust bearings
as in a marine transmission.

They sure do. If they didn't, they wouldn't last very long.

What utter rubbish!
There are motorcycles out there that will withstand thrust directly down
the output shaft?
Frankly i dont belive you.
even shaft driven bikes tranfer thier power through turning motion only the
shaft is only subected to torque. not thrust.

A boat prop Pushes the shaft forwards... which via the gearbox
bearings......pushes the engine... which takes the boat forwards with it cos
its bolted to the boat!
Its one of the reasons that boat engine mounts are a tad more costly than
engine mounts for almost any other use.
Select reverse.. (not a lot of bikes have reverse... a few.. but not many)
and the shaft pulls .. I'd guess that would be very sudden death for most
non marine gearboxes.