New to me maxim 400

[NTOLERANSE]

Hello all, my name is Doc, and i just picked up an 82 400 maxim.

Figured this would be a good bike as a starter ride for my soon to be 16 year old son.

I traded for this bike on craigslist. Had an old trailer i didnt want anymore so i made the trade. Maybe some of you members saw it posted on milwaukee craigslist?

Previous owner had an engine issue and had a friend take it down. Seems to have lost a head gasket. Im not entirely sure thats all thats wrong with it but the rest of the bike wasnt terrible - decent paint, seat tires chrome ect.

Anyway here is a pic before it was taken apart.

Anyone got an engine....i may need one.....

 

[bentwrench]

Welcome!

I did the head gasket on mine - check the restoration thread in my sig file. Not that big a job - I had a baby girl in the house, so it took me much longer than it would otherwise take most people. Most important thing I learned: make sure that the replacement head gasket specifies it's for the DOHC XS400 (either Maxim or Seca, which are interchangeable.) My first set was for the SOHC, which is far more common, but doesn't fit.

Post questions here, and all us DOHC guys will do our best to help out! And of course, search is your friend (just specify DOHC for engine specific issues.)

 

[NTOLERANSE]

Thanks. How did you replace the seals under the cylinder bores? How do you put the pistons back into the bore is there a special comressor?

 

[bcware]

I would download the manual from here and give it a good read. My old SOHC '78 has tapered barrels; the only thing needed to get the pistons back in is patience. Perhaps yours is similar.

Are you specifically asking about oil seals or gaskets under the cylinders?

 

[NTOLERANSE]

Hard to tell whats under there, i didnt want to pull it off all the way until i was sure i knew the proper way to get the cylinders back on. Looks like a flat o ring.

 

[bentwrench]

Do a search for manuals. There's a thread with all of the XS400 manuals posted - the one that will work is the 1983 DOHC Seca manual (the only differences are cosmetic: tank, body panels, wheels, rear sets, etc.) It has everything you need.

I only did head gasket, I didn't pull the barrels. Others have done the barrels, but I don't think on the DOHC engine (so you'll be a trailblazer, at least on this site.)

Oh, but Athena (I think) makes a complete engine seals set. I've seen it for less than $100 on Ebay, while just a head gasket usually goes for $50. The set makes more sense, as there are a couple of seals that you'll have to remove to get to the head gasket.

 

[bentwrench]

Ta daaa:

http://www.ebay.ca/sch/i.html;jsess...om=R40&_sacat=0&_nkw=xs400+dohc+gasket&_arr=1

 

[NTOLERANSE]

Amazon has a complete kit for under $60.00. I d/l the seca book from this site, man that thing is hard to read. I may print it out. My kid is kinda excited about this, anything to get him off the Xbox.


EDIT - that may be a single cam kit....verifying with seller.

 

[NTOLERANSE]

Heres a pic of where the bores separate. Definitely seals there.

 

[NTOLERANSE]

Scored a full gasket kit of ebag. Ill be getting things together soon.

 

[Maxim-umm]

I did a top-end rebuild and replaced all the gaskets on my 82 Maxim DOHC. It was a surpirisingly easy task. Just take your time and take pictures. The best thing about these engines is their simplicity, so don't be intimidated by any task. This site is full of great info and talent, so ask away with questions and concerns (after searching, of course... ) Good luck!!

 

[bentwrench]

Ksqrly thinks he may have blocked an oil passage to the top of the head. Is there a channel through the base gasket that you can remember?

 

[ksqrly]

I think you were talking about someone else bentwrench. I have yet to tare into my engine.

 

[ksqrly]

Yep just read the thread it was keithp

 

[NTOLERANSE]

Started cleaning parts for reassembly. What are he little o rings for under the bores between the bores and the cylinder case? I have new rings, just dont understand what they are sealing?

 

[bcware]

The large red o-rings that go around the jugs? I think they just help keep oil off the base gasket area.

 

[bentwrench]

Without a picture I can only guess, but there are oil passages that carry oil up through to the head. That's probably what you're seeing. Very important.

 

[NTOLERANSE]

Couple of questions..... Does the front cam chain slider just drop in.

On the right side of the engine the two big head bolts have a copper type washer, but left left side doesnt.

And are these the right nuts for the head studs?

This thing was apart when i got it so i dont have the take apart experience

 

[16VGTIDave]

Oil for the cams is fed up along the right studs. They need the copper gaskets or oil will leak out.

 

[NTOLERANSE]

Thanks Dave