'82 650 Maxim, '83 750 Midnight Maxim. Engine swap?

I have an '82 650 Maxim, and have come across an '83 Midnight Maxim (which I assume is a 750- someone please correct me if I am wrong).

The '83 is for sale for $250- which is a good price for a bike that is basicly complete.

The seller tells me that-

"I have some of the parts to fix it. About $300 of parts(no time to work
on it). If someone had money to put into it it would be a great bike.
Engine is good the transmittion needs work (I have the gears),also the oil seals on the
forks and the carburators need work and needs new battery. Has new tires, handle
switches, clutch, and brakes new throtle cable, seat is great."

Bike seen here; http://phoenix.craigslist.org/mcy/300263972.html

So, if I go to check this bike out, and see that it is in decent shape I would probably want to either put the engine in my 650, or just fix up the Midnight.

My question is, how compatible would an 83 Midnight Maxim and an 82 650 Maxim be?

I understand that a regular 750 engine could be swapped into a 650 frame, and the carbs can be used (rejetting required)- is it the same with the midnight maxims?

Any info is appreciated!

-Shawn

 

It should be an easy swap- the engines are the same below the cylinder base gasket, and the external difference upstairs is only a quarter inch or so.

If you're getting the entire bike, just clean the 750's carbs and use them.

What exactly is the transmission issue, and what parts are included in the deal. More important- can you split the cases yourself, or will you need to farm the job out?.

 

I've never split any cases. The deepest I've gone into an engine was taking the valve cover off to check clearances and the cam chain. however I consider myself slightly mechanically inclined, so I would probably try to do whatever it takes myself, as I have more time than money.

I am still getting more info on the bike from the guy, I was mainly wondering about the capatability of the two engines to each other.

Why do you ask about splitting the engine myself (if not only for obvious reasons)?

 

Because that is what's needed to access the transmission parts. You can see the parts just by pulling the pan, but that's where the fun ends.

Anything inside the gearbox that spins will not come out until the cases are split. It's not a great choice of tasks unless you know what you're doing and have all the right tools...only one way to do it right, and many chances for things to go wrong. Boo-boos will be very expensive.

My suggestion for you is to pass on this bike, and wait for a healthy donor-engine.

 

Wouldn't it be just grand ... if we could pull-off the Shift Lever, take-off the Shifter Cover and find ... oh, ... six, eight or ten fasteners holding-on a cover that would come-off and let you extract the whole transmission???

That'd be nice; for sure.

But, it's not like that. XJ Transmission work involves taking the whole damn engine apart ... until there's nothing left to take apart.

That being said ... You could put your 650 in that bike and ride it ... while taking your sweet time to fix-up the 750 ... making that 750 engine a fully ported and polished, race-prepped, totally pimped-out, phat-azz aluminum polished, bling-machine that will scream like a tortured banshee escaping from the grips of the Devil, himself!

Just a matter of time.

 

My 650 runs just fine in the frame that it has.... I would like to have a bigger bike. :-( it seemed so nice

 

The Midnight on craigslist is a 650,not a 750.

 

The shifters are different.
See bottom post on this link:
http://xjbikes.com/Forums/viewtopic/t=3608.html