1981 Yamaha XS400 - New Member

AMPd

XS400 Member
Messages
17
Reaction score
3
Points
3
Location
Homestead, FL
Good morning,
Just picked up a 1981 Yamaha XS400. Im real excited to get this thing to where i want it.
Traded an old Jeep Cherokee I had sitting in my driveway for a couple years now with no future in sight.
Real excited about this bike, seems to have a lot of potential and runs so much better than I expected it to at this point.
Full disclosure, I have no idea where to begin with this bike. I am completely new to these machines, it my second bike and surely have no idea what I got myself into but I chose this bike really as a long term build, taking my time to learn about them and to get it where I want it.
That being said, im seeking expert advise on WHERE THE HELL TO BEGIN!
What do you all recommend I start with? Im sure i need to clean out the carb, clean up the wiring, maybe take a good look at the engine, just need some recommendations in order to get it moving.
Im attaching some photos of the starting product for you all and look forward to reading all your responses.
Thanks again!
 

Attachments

  • IMG_0438.JPEG
    IMG_0438.JPEG
    123 KB · Views: 430
One question I have, and again please excuse my ignorance, is why this bike doesn't seem to have a master cylinder? Bike brakes okay but not as well and id like which is why I want to service the brakes before I move onto anything else on this build. Again, any responses are greatly appreciated.
Thanks again!
 

Attachments

  • IMG_9207.jpg
    IMG_9207.jpg
    54.1 KB · Views: 370
  • IMG_9203.jpg
    IMG_9203.jpg
    63.8 KB · Views: 347
It has drum brakes. No hydraulics, no master cylinder, just cables.
Carb cleans are always good. Check wear levels on the drum brake shoes.
 
These brakes will work fine if they are setup correctly and are in good shape. The best thing you can do to keep it running well is to keep the stock air filter setup and stock exhaust!!
 
Thanks for the replies guys. Going to start taking it apart tonight after work and see how it looks.
Found a couple write ups with suggestions on this forum about how to go about it, doesn't seem like too big a headache, I also found the
owners manual pdf on here, great stuff!
As far as the rest of the bike, my plan is to keep it as stock as possible, not looking for extra power, just a nice little build for myself.
One question I do have is I would love to keep the stock exhaust but the previous owner explained he had a crack in the crossover pipe so he cut it off and welded the two pipes closed. Any chance that will have any negative affect on the bikes performance? Can I simply wrap the two pipes and maybe swap out the mufflers or would it be best for me to find a stock replacement for the exhaust.
Thanks again!
 
Last edited:
The cross over would be a big performance loss if it was removed. Post pics of what he did. Good stock ones are getting hard to find. A lot of people cut them up thinking it will make more power because they are louder. Nope, not the case.
 
Snapped a couple photos here, looks horrible in my opinion, might have to start looking for full replacement.
 

Attachments

  • IMG_9215.jpg
    IMG_9215.jpg
    79.2 KB · Views: 334
  • IMG_9216.jpg
    IMG_9216.jpg
    53.4 KB · Views: 306
  • IMG_9217.jpg
    IMG_9217.jpg
    62.3 KB · Views: 338
Welcome! As a fellow owner of a blue 80 XS400G, I'm happy to report it's common knowledge that the blue bikes are the fastest. They're so cool looking it helps maintain good operating temperatures for performance.

Exhaust: right one looks like it has a decent stub. Presume left is same. Not sure if anyone can confirm but presuming it is simply a crossover tube without any inner workings I'm guessing you could angle grind it back closer to base and have a replacement tube welded back on. I just paid $60 to have mine welded shut because PO drilled holes in the back for volume. Not cheap but cheaper than buying replacement and I didn't mind paying local shop. Already runs better and less annoying.

New to the bike: the manual is first stop shop and we would all benefit from referring to it first. One of them posted (Haynes) is actually searchable which is gold. Also refer here: http://www.xs400.com/threads/how-to-what-to-do-first-with-your-new-xs400.10595/
 
That sounds like a great possibility as far as the exhaust is concerned, Ill be taking it to my regular bike shop and seeing what they can do to salvage it.
I already got the manuals pdf, great stuff! Ill begin working on cleaning out the carb and replacing the fork seals this weekend. Considering changing out the front drum shoes while I have the wheel off, any tips or advice on all this?
 
Just a small update, spent sunday working on the fork seals. What a damn headache. Pushing the inner fork cap down in order to get that c clip off is the worst. Finished one and busted my fingers TRYING to get it back assembles. Many thrown screwdrivers and kicked pallets later, still not back together. Had a beer, took the Harley out and decided ill try again tonight. Patience and luck seems to be the key so hopefully luck is on my side tonight.
Im attaching a few photos here.
Wheel removal exposed the brake shoes, clearly ill be replacing those, seem to be the same damn ones that have been on the bike since 1981.
Also a picture of the removed fork seal next to the brand new one, ill tell you, without a heat gun, youll never get those old seals off.
Ill keep you all posted on any progress.
 

Attachments

  • IMG_9245.jpg
    IMG_9245.jpg
    80.1 KB · Views: 336
  • IMG_9246.jpg
    IMG_9246.jpg
    74.4 KB · Views: 319
  • IMG_9248.jpg
    IMG_9248.jpg
    47.1 KB · Views: 336
  • IMG_9250.jpg
    IMG_9250.jpg
    100.3 KB · Views: 343
  • IMG_9255.jpg
    IMG_9255.jpg
    118.3 KB · Views: 393
Finally got one of the forks done and rebuilt. Incredible how much help a vise and pick work. Got the second taken apart and ill be rebuilding that one this afternoon.
Im breaking my head trying to find a front brake line (brake drum). Any advice?
 

Attachments

  • IMG_9267.jpg
    IMG_9267.jpg
    80.6 KB · Views: 321
  • IMG_9270.jpg
    IMG_9270.jpg
    66.7 KB · Views: 304
Im breaking my head trying to find a front brake line (brake drum). Any advice?
Just buying a line? Not sure where to buy from but just measure stock and find something similar length. Is the existing one pretty gutted? For the brake itself you can just clean it in there and Resurface shoe liner with light sanding or replace with new.

By the way - I did my drums only to find out I should have done a better job cleaning the 2 openings for the actuators. There was heaps of sticky shiyt there that caused my brake not to release as it should. I'd remove them, clean, perhaps grease lightly, and reinstall. There was some fiber liner to protect crap from entering the drum which I'd keep if you have it. Take care not to get grease inside / by drum liners. See pic: Red area was grimey under/around the spline. If removing try to keep green bolt from spinning on itself. It adjusts angle of the 2 arms which you want to be the same so they actuate together at same rate.
IMG_20190208_194301 - Copy.jpg
 
Looks like you can get a brake cable here www.rockymountainatvmc.com Not sure of your year but the one I found is about $14 there. they show it on back order but it's only a couple of days out. Motion Pro will make them to your spec but they get kind of spendy.
 
Thanks for the tips guys.
Got a stock brake cable and ebc brake shoes coming in today, hopefully i have the front brakes done and functioning by the end of the day. Ill update later.
Any other tips and advice before i dig into it?
 
Hey guys, im back. Been unable to work on the bike for a couple weeks, between vacation and work once I got back, its been impossible to find any free time.
Last night got home and realized there was a strong fuel odor in the garage, first time I ever smelled that.
Rode the Harley to work the week prior so checked that first but everything was normal there, then i noticed a tiny puddle under the xs400 (it was fuel) and realized there is a minor, slow leak coming from the airbox area. Removed it and noticed the stream was coming from the inside of the left side boot down to the side kick stand.
Any idea what this could be? I didn't notice until real late at night so i stuffed a new microfiber cloth in there just to absorb the fuel but Im on my way home now to try and figure out whats going on.
Thanks in advance for any help.
 
Petcock not shutting off and then your float valves in carbs are over flowing. Make sure fuel isn't in the oil.
 
Chris
Thanks for the info. What do you recommend I do as a temp fix for the moment just to stop the leak, at least until the weekend when I have the time to do what I need to do.
Thanks again in advance
 
Pull the fuel hose off and plug it. A bolt works well. Then when you can fix the petcock and then carb floats.
 
Back
Top