1984 Maxim 400 Resurrection Project

Hello everyone and welcome to my project thread. In this thread I will be posting progress I make through resurrecting a good old 84 Maxim 400 that I picked up for $50. It should be a fun adventure and let's hope I succeed. Here are the pictures of the bike when purchased. I will post my progress that I have made in the last few days shortly.

 

Interesting backrest on that one.

 

Lol, that is the grill to cook road kill on in case I get stranded somewhere.

 

Okay, so today I removed the carbs and the engine.


Carbs look cleaner then I expected from an external observation.


Next I drained the oil and removed the engine. The bolts came free a lot easier then I was expecting after having trouble with the spark plugs.


Now for a little bit of inspection with a flash light. Oh no! Rust! D:


Well that's no good... Let's see what's under the cylinder head cover. Oh good, at least it looks clean in here.

And that is as far as I got before the mosquitoes started eating me alive and I had to pack up the tools and such.

 

Well I am back from my little vacation and am back to working on the bike.


I got the head off, but one of the pistons is seized, so I have it soaking in diesel right now for a few days to hope it frees.

Here is a shot of the bottom of the head. I am going to soak the head in Evapo-Rust to get the rust off the valves before trying to remove them.

 

Wow that engine's nasty! I'm just ***finally*** finishing my 82 Seca 400 (exact same bike, different seat, tank and forks.... and I get a 6 spd trans!)
PM if you have any questions as everything's still fresh in my mind! Also, when it comes to to check the valve clearance let me know if you need any shims, and have several different increments lying around, I'd be willing to swap with you!

 

I looked at the Yamaha Parts Site.

Pistons and Rings:

Pistons:
2nd O/S 0.50 mm (0.0196) 20-thousandths over.
4th O/S 1.00 mm (0.3930) 40-thousandths over.

Rings:
(Also 2nd & 4th)
..........

Then I looked for the Parts:

3 12R-11631-00-00
PISTON (STD)
$67.93 $67.93 2 OBSOLETE
3 12R-11638-00-00
PISTON (4TH O/S 1.0OMM)
ALTERNATE PART
$58.80 $58.80 2 OBSOLETE
3 12R-11631-00-00
PISTON STD (STD)
$67.93 $67.93 2 OBSOLETE
3 12R-11636-00-00
PISTON (2ND O/S 0.50)
ALTERNATE PART
$67.93 $67.93 2 OBSOLETE
3 12R-11638-00-00
PISTON 4 O-S 1.00 (4TH O-S 1.00
ALTERNATE PART
$58.80 $58.80 2 OBSOLETE
3 12R-11636-00-00
PISTON 2 O-S 0.50 (2ND O-S 0.50
ALTERNATE PART
$67.93 $67.93 2 OBSOLETE

 

ebay is your friend for parts for these bikes. I got new OEM head and base gaskets for under $30 shipped!!! The head came from south africa and took about 3 weeks to get here though!

 

Any progress on this?

Your tank and fenders (front & back) look to be in pretty good shape. You also have the left side middle plastic cover. That's a hard piece to find. I have the right side plastic cover, although it no longer matches my bike since I replaced the tank.