1982 Maxim 400 Complete Tear Down and Rebuild

OopsAboutThat

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Hey,
So I recently purchased a 1982 Maxim 400 for $400 with the goal of completely restoring it. The bike doesn't start and the PO said the butterfly valves were seized. My dad and I decided this would be a great fall/winter project and we'll hopefully have it running by the summer. I'll be adding pictures as I progress, but you'll have to forgive me for the cell phone quality pics. :shrug:

This is what the bike looked like fresh off the truck:
XMs29ic.jpg


After getting it home we did a quick once over and noticed that the PO did some really weird stuff to the electrical. For instance when another key on the same key ring touches the handlebars the whole electrical just shuts off. :wtf: Looks like that's gonna take some work, especially since neither of us have much experience with electrical.

Day 2:
Took the seat, tank and carbs out. The tank had about 7 litres of roughly 4 year old gas in it and took forever to drain. After taking the carbs out, being the genius I am, I managed to spill old gasoline all over myself. :doh:
Progress:
2dXjaZI.jpg


Day 3:
Today we managed to strip the whole bike down to its frame. It took us about 4 hours and we used lots of ziplock bags for parts and found out just how spider infested the bike was. :yikes: We managed to organize everything relatively well although we still have some loose screws kicking around that we're not too sure about. The chain is rusted real bad and there's a bunch of dirt and grime coating the inside of the cover where the chain connects to the sprocket.
After about 2 hours:
VduxXLw.jpg


Taking the handlebars/forks/gauges was a real pain in the ass, but we got it all apart and took off the sub frame with some mild persuasion from the impactor.
End of today:
9D1DqqI.jpg


Our next goal is to clean almost everything, sandblast the major parts and get a primer coat on the frame and body pieces.

I'll be posting our progress along with any major issues we face. All help and feedback is greatly appreciated.

Thanks! :cheers:
 
Looks like a lot of work done so far and never seen such a strange looking frame in my life LOL.Then again I haven't been around a lot of motorcycles either.
 
A couple of things to get you going. Check that the linkage is not bent, causing the butterfly's to not move. Spray the butterfly valves with penetrating oil and work them slowly until they are free. You can clean them more when you disassemble the carbs later. Don't be surprised about the grime behind the sprocket cover. Everybody's can get like that.
 
Thanks for the welcomes and feedback! Got the butterfly valves unstuck today, thanks for the advice Specdog, it definitely helped. Took apart the carbs and found that the PO had stripped one of the the main jets like no other :banghead: :
tfZ7tea.jpg


Most of the day was spent building a fully ventilated sandblasting/painting booth in the garage.
Pictures of the booth:
4cyF2Es.jpg


TidImQU.jpg

We're using a cheap Maxus 20lb blasting kit with glass beads as media. It goes through a lot of media, and pits soft metals a bit, but it's waaaaay faster than most other ways of removing rust and paint.

9tSfZQl.jpg

On the left is where we blasted for about 30 seconds, and the right is a pretty sad attempt using a wire brush for about a two minutes.
 
Nice setup:thumbsup: Blasting is the only way to clean stuff. Get some baking soda and do the carbs:wink2:
 
Hey all, quick question. Does anyone know the stock size for the main jets on the Maxim 400? Definitely going to need new ones and I'm a little unclear on what size to get. Thanks!
 
Haven't posted for a while, mostly because all I've really been doing is sandblasting. Got the frame, swing-arm, sidestand, license plate bracket and some metal piece done and primed. I was really impressed with the way the glass beads strip the metal and leave it looking real purdy.

Frame Stripped:
VZ8ckdn.jpg


Primed:
U0SOref.jpg


The other parts primed:
zDnG1V2.jpg


Next thing to do is wet sand and prime all the plastics and the engine exterior. Thinking of doing an all gloss black lacquer paint job, but I'm definitely open to suggestions!
 
... Thinking of doing an all gloss black lacquer paint job, but I'm definitely open to suggestions!
I'd miss the gun-metal grey swing-arm just a bit, but think gloss black would be an improvement.

As long as the tank is red, you can't go wrong ... :wink2:
 

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Thanks for all the suggestions! I think we're gonna go with a black frame and paint the tank and all the plastics a deep red. Might do some Kanji and hirigana on the top of the tank.
We were thinking of painting something like this, but a lot cleaner. (Writing with a computer mouse isn't that easy :shrug:)
QQbYBZz.png


I'm relatively sure this translates to "Eat shit and Die" in Japanese, don't think I'll tell people that. :wink2:
 
Hey everyone,

I've been gone for a very long time, life got in the way and all that usual stuff that people say when they lose their direction with these projects. But, I'm back now and I want to finish this thing more than ever. I made just about no progress while I was gone, but I have a much clearer idea of what I'm wanting to do with the bike now. I've decided I'd like to turn it into a soft-tail bobber, the look of the exposed monoshock has always appealed to me.

I would like to do something like this with the frame:
lOY7mr4.png


I've heard that the triangle under the seat is what spreads any down force across the frame and if I were to get rid of it, the frame might not be sturdy enough. I've seen people replace the monoshock with a piece of rectangular steel tubing. My main concern here is if the monoshock will provide enough "structure" to keep the frame safe. If not how I should go about bracing the frame if I were to chop it like in the picture above?

The picture I posted is from this thread, but the support for the frame was never really discussed aside from when the OP mentioned he made some braces.
http://www.xs400.com/forum/showthread.php?t=8768

Thanks everyone for bringing back my inspiration and ideas, and for finally getting me up off my lazy ass. Let's just hope I don't get lazy again :wink2:
 
Okay bobber style, to me that means old school solo seat and simplicity. If it were mine I'd locate where I want that seat to reside in relation to everything. Do you have the handlebars you want to use? As that will also help dictate seat placement. Hopefully Yamaha has already made it close to optimal in their original design. It's probably pretty simple to modify the existing seat into a solo one. Just make sure you've got some wiggle room (ass space) as you don't want to have it too short. Then where that seat ends, weld in some cool smaller supports (mini triangles). Then aft of that, remove the back half of the triangle as shown above. It appears that the DOHC 400 uses the engine as a stressed member so the swingarm mount point and the shock mount should be fine without the triangle frame structure. Which was mainly there to support two people and the rest of the stuff back there. I'd probably weld a small fender extension to the top brace of the swingarm to keep crap from flinging up on me too.

This is one of my builds (Virago XV535) which I did similar mods.

 
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