81 XS400H – putting the Trusty back into Rusty


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Southern NJ
Hi everyone. I just got my title to a just purchased XS400H and joined the forum. What a great resource this place is! I have already availed myself of the posted Service Manuals and they are going to be invaluable – thanks to those that took the time to scan and post them.

My bike has suffered the indignities of living outside for quite some time and looks pretty sorry from the neglect:


However, there are some nuggets of gold under the sun bleached paint, rust, dirt and bird poop.

What I like about the bike -
  • It is pretty much all there and original. If I can believe the odometer it has been ridden just over 7000 miles.
  • I have done a quick look over the electrical system and the loom is completely intact with all of the proper connectors per the electrical drawing. No one has hacked it up and there are no added “accessories.”
  • Most likely no one has been in the engine as the factory anti-tamper plugs are still installed on the ignition pickup cover and over the carb pilot air screws.
  • The engine kicks over freely and has compression.
  • The frame is original – no one has chopped off any mounts or frame bits.
  • The aluminum engine side covers have no scrapes or other road rash.
  • The fuel tank is almost perfect outside with one small dent in the top.
What I don’t like about the bike -
  • No keys. I will be pulling the ignition switch to get the code and have new ones made.
  • A few key items are missing that I will have to source – center stand, headlight, mirrors, the seat latch rod and spring and associated lock (probably removed because of not having the keys).
  • Pretty much all of the rubber components have perished (especially a big tear in one of the carb intake boots, both carb holders on the engine have big cracks, the rubber relay holders for the headlight and safety relay are torn, and the foam on the air filters have been reduced to powder).
  • The instruments on the dash look to be DOA as the rubber seals are shot and water has surely reeked havoc inside.
  • The fuse box is cracked and not usable.
  • The front drum brake seems frozen.
  • There is a lot of rusty and dirty stuff that will absorb countless hours of my life.
  • Oh yeah, I really am not a fan of the buck horn bars and the king-and-queen seat (don’t worry, I won’t throw them in the dumpster!).
My plans -
I am not going to do a formal restoration, but more like a resuscitation. I plan on using the original parts where I can and replace only what doesn’t work. After that – ride it.

This is really going to be a winter-time project for me. I got the bike a bit early because I couldn’t pass it up. So right now I will only pull components off of the bike to prevent further deterioration and allow me to evaluate condition. Stuff like the tank, carburetors and electrical bits will be brought indoors right away. Other than that, I will keep it as a “roller” and tarp it until I can move it into my shed over the winter for the real fun to start on Trusty Rusty.
Welcome to the forum. If you need any stock parts just let me know as I have lots of stuff for these bikes. I do see the bike has a aftermarket Mac 2-1 exhaust on it.
xschris - thanks. As I assemble my soon to be expanding list of needs I will keep you in mind.

Yup it has a 2 into 1 exhaust which I will run with, at least initially. The down pipes with this setup are awfully close to the lower front engine mounts on the bike, and I think with normal vibration might rub. I may have to use thicker or doubled exhaust pipe gaskets to get some clearance. But I haven't thought that through a whole lot yet!
I wondered why anyone would remove the center stand on a stock bike. Now it makes sense. A center stand is pretty damn useful for just livability and maintenance with the bike. I am not sure the Mac is going to make the final cut.
BTW, thanks for the info on the Mac exhaust/center stand interference issue. That is a detail that only experience shows you. I would have never figured it out until springtime and even though it is some bad news, it is surely better to know now and be able to plan for it with a clear head.

I have to say there was a voice in my head last night saying, "Get the welder out." The Mac now has two strikes against it and I either get stock pipes or try to modify the Mac system. The Mac doesn't look especially well made, so maybe there is not much risk in chopping it. Anyway, I have some time to consider things as this will not be something I would tackle soon.

Again, thanks for sharing the details.
Don’t cut anything. Those are like $300 new and someone may want it for some cafe/chopper bike.
So I got to pull a few things from the bike today between other projects. The fuel tank, the carbs and the dash are now off and safely indoors. I managed to release the latch on the tank cap with the help of past posts on this forum and got a good look inside. There are some rust patches, so I am going to have to address that:
Inside tank.JPG

The petcock did not have a standpipe on it when I removed it, and I am pretty certain it is not in the tank, so a past owner removed it. Not surprisingly the petcock was jammed with rust:

I pulled a vacuum on the petcock and it won't hold it, so a full rebuild is going to be in the works.
I put some mineral spirits into the tank and agitated it off and on today just to help loosen any goo and rust (it did) and finally dumped in some two stroke oil and coated all of the inside surfaces before buttoning up the tank and putting away:

That is not all of the cleaning I will do, but just a way to assess and stabilize what I have until I get going this winter.

Next up are the carbs which I hope to look over in the next few days. Spoiler alert - black goo leaked out of the drain of one of them when I opened it. Shocking, I know.
Awesome; I'm in the same process. I'll agree with the thought of saving the MAC 2 into 1... I sold the one my bike came with and used the funds to buy pretty much everything else the bike needed:)
Thanks AmbientMoto. I will definitely save the Mac. I may have to initially run with it anyway as I sort out getting a replacement OEM set of pipes and hangers. There will be lots to do this winter on the parts procurement front.
Trusty Rusty received a quick carburetor analysis this week. As I mentioned, some really thick, black goo came out of the bowl drains when I opened the valves and let the carbs sit overnight, so I was expecting a pretty bad sight when I finally took off the float bowls and looked inside.
Goo in Carbs.JPG

The floats as well as the slides were stuck and there was a lot of thick schmoo in the float bowls. I wanted to at least get things unstuck so in the future I won't need more force than necessary when removing the internals for cleaning. So, I put the float bowls back on and filled the bowls with Berryman B-12 for an overnight soak. Since the float valves were stuck, I found that filling through the fuel inlet was impossible, so I injected the B-12 into one of the two bowl vents and kept adding until I got overflow from the opposite vent (vents circled below.) Then I just walked away until the next day.
Seafoam Soak.JPG

The soak ended up working really well. What drained out looked like expresso (didn't smell as nice), but the slides and float valves now moved freely.
Carb bowls1.JPG

I sprayed all of the internals with WD-40 and buttoned everything up until I get to a full cleaning. The jets that I could see (main jet and pilot air jet) are stock sizes. After some of the used B-12 flashed off, the sticky residue I initially found in the carbs was in my drain pan.

Goo flushed from carbs.JPG

I plan on all new rubber parts in the carbs, and based on how bad they look, I have pretty much convinced myself to give them the full "spa" treatment by getting an untrasonic cleaner. Next up this weekend will be a look over of the electrical system.
Be careful with cleaners around the diaphragm s as they can get destroyed very quickly.
xschris, thanks. I was pretty careful to keep the solvents below the throat of the carbs. I didn't put any on the slide pistons as I figured the jet needle was "glued" into the needle jet by the goo and was causing the binding. At least now when the pistons are moved I can hear air movement and feel and see damping resistance, so I am hoping the diaphragms are intact and reusable at this point.
I would get them out and check for cracks. I use red rubber grease on mine to keep them during storage and use.
xschris - I have no experience with the red rubber grease. It is not widely available in the local auto stores that I know of, so is probably an item that would have to be ordered. I do know folks use it on hydraulic brake seals and master cylinder o-rings instead of just using brake fluid. I second Buddha's request for more info as we all may learn something new here. I normally lube o-rings that have to provide a moving seal with white lithium grease, but am game to get some RRG and try it out.

I guess my question is: it red rubber grease beneficial for wide use on these bikes? I know it can be used on brake soft goods and now carb diaphams, but what else should we consider using it on that provides advantages?
https://www.ebay.com/itm/272398105549?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649 This is what I use. An old Yamaha mechanic from back in the day swore by it. With all the spare carbs I have and the ones I use I wanted to keep all the diaphragms from going bad. I used to use lucas red and tacky but was told to be much better. I still have diaphragms from the 70's in perfect shape so I guess I am doing something right. The other rubber parts on the bikes get meguiar's supreme shine protectant.