The Mule: '77 XS400

[scott s]

Hello Ladies and Gents!
I've actually been a member of this forum since it was first announced at XS650.com. I've just been lurking, but now I have an XS400.

The name "The Mule" has a meaning behind it but, for now, it's sort of Top Secret. It will be revealed soon enough.

Today, I hauled home this '77 XS400. The P.O. bought it as not much more than a rolling frame. It's something of a Rat Bike, but it runs pretty darn well (and will soon run even better!).
It was missing the wiring harness, so what's there is very rudimentary. On/Off switch, headlight and tail/brake light.

It's kick only for now, but the starter is there. We'll probably hook up the starter in the near future.

Here are a couple of pics from his build, and one of how it looks today.

 

[scott s]

I haven't even had a chance to ride it yet. The weather here is horrible. It stopped raining when I picked it up, but the streets were still running with water.

He told me that it doesn't like to idle and probably needs a proper carb cleaning. He had removed the baffles and was running open pipes. Before I even took it out of the van, I re-installed the baffles.

 

[scott s]

It also had the EMGO (or similar) pods on it. I swapped those out for genuine K&N's.

Before:


After:

 

[scott s]

As you can see, it's dirty and dusty and covered in sawdust. It started on the 2nd kick, though!

One thing I would like to address are the foot controls. It has the GP style shift pattern because of the home made "rear sets"; 1 up, 5 down.
I'm not too crazy about that. I thought I had a source for rear sets that would mount on the passenger peg hangers but, as you can see, they have been cut and relocated.

 

[briansal]

That's a sweet bike. Any chance you know off hand the KN part number.

 

[scott s]

The pegs are solid mounted. Think I could figure something out to run an actual linkage and proper (1 down, 5 up) shift pattern? Any ideas are welcome.

The front brakes work great and have a new master cylinder and braided hoses.
The rear doesn't feel too hot. He thinks it's the old hose, but I'm wondering if it feels spongy because the pedal is so short and has no leverage?

 

[scott s]

That's a sweet bike. Any chance you know off hand the KN part number.

I do not. I bought them off a member here, in the classifieds. I think they're an older version.
I'm willing to bet that they, along with the baffles, will help the carbs run better, even before a proper cleaning and synch.

EDIT: Doing a search for "pods" turned up the For Sale thread. They're RC-130, at least that's what the seller says.

 

[scott s]

The rear brake stuff inside the frame is all still stock. The master cylinder, plunger, etc.
He only cut and shortened the pedal and made a linkage. It doesn't seem to have much travel and feels very tight.

I'll look into it and see how it feels on a test ride as soon as weather allows.

Another reason I'd like some better rear sets are because this bike is pretty cramped for me. I'm 6'2" and I'm tucked up pretty tight on it.

More good stuff: The front tire has less than a season on it. The chain and sprockets are new. New fork seals. The tank is very straight and pretty darn clean inside; just a little flash rust on the part that's sat above the gas.

Overall, I got a great deal on it and it's a solid, good running base. Just a little tweaking and tuning and it'll be even better.

 

[scott s]

I'm an SOHC4 guy (CB500 and CB550's), and "pods" are a dirty word over there. I've used them on my XS650's before with no issues at all.

I'll do a search and read up on it, but can anyone enlighten me on pods and the XS400?
With a stock engine, the pipes/baffles pictured and the K&N pods, what would be a good starting point? Do you guys re-jet? Raise the needles? Etc.

 

[xschris]

Nice filters you have there First thing with the carbs is to make sure they are clean and adjusted proper ( floats also). See what size jets that are in it and make sure that the idle air mix screws have not broken off in the carb bodies (very common with the 77-79 years). Then with a 42.5 pilot jet, the jet needle on the third clip from bottom and a 142.5 main set the idle mix screw to three turns out. Make sure you sync the carbs with a manometer. That should be a good starting point with your set up. Then if it's still lean you can fine tune with a little more jetting.

 

[xschris]

One thing I notice that will be a big issue for the bike is your case breather pipe is plugged off You need to hook it up to the carbs H-pipe or your bike will not run right and will cause damage to the engine!!

 

[xschris]

Like this. I also notice that you have a set of 80-82 bs34 carbs on the bike witch are built a lot different than the 77-79 ones. The idle mix screws are not like the early bikes but are like the 80-84 xs650 ones.

 

[scott s]

Thanks, Chris. I'll check that out. Like I said, I just picked it up. It POURED rain all day yesterday and only stopped long enough to load the bike in the van.

 

[scott s]

The P.O. told me that he got the bike with no wiring harness and that it had a "rudimentary" harness on it. He wasn't kidding...

Luckily, my friend is an electrical engineer and we'll definitely be cleaning this up. We'll also be installing a relay that cuts off the headlight when the bike is in neutral so that it'll be easier to kick start.



New coils, wires, and caps are on the way, too. We installed new plugs yesterday, and changed the oil.

 

[scott s]

One reason the bike didn't like to idle, don't ya think?



Vacuum for the petcock was off. We also found that the idle mixture screws were set at 3 1/4 turns out on one carb and 1.5 turns on the other.
We pulled the mixture screws and blew some carb cleaner and compressed air into the orifices. Installed new O-rings and set them at 2 (or 2.5...I can't remember now) turns out and the bike will actually idle now.

We tried to set the points, but the screws are stuck tight. That will be addressed when we go through the ignition system.

A couple of hours of fiddling around yesterday and I was able to ride it around the neighborhood and make it idle properly. All in all, it's a solid base and I'm sure that, if I keep tweaking and tuning, it'll be a fine running lump!

Oh, and XSChris, I did turn the barb for the engine breather around so that it's facing the correct way. I just have to get a short piece of hose and connect it up properly.

 

[scott s]

Also ordered these up from eBay. Only $36 shipped. I'll be able to figure out something a little better for the rear sets.

 

[xschris]

If you are running points make sure you get 4ohm coils.

 

[scott s]

New plugs, wires and caps....that can only help.

 

[scott s]

We figured out a way to mount a battery that would actually turn the starter. No more kick only.
The starter button and solenoid are only temporary in that location.

The battery is still pretty stealthy.

 

[scott s]

Can anyone tell me what I'm missing from the tach drive? I'd like to add a tach if it's simple enough.

Also, what's the ratio for the XS400 tach and speedo?