Intro and starting question

[bikerbob]

Hello Everyone! I've been creeping on this forum as a guest for a few days and I think I have found the very first forum with no haters, way to go guys. I bought a pair of xs400's on craigslist for $250. No titles, one is complete (sorta) and the other is mostly there and mostly in boxes. Both have VIN's that start with 2LO, (o or zero?) one has a date on the label on the neck of late 1977, and the other late 1978, I don't recall the months of either. I suppose that makes them a '78 and a '79. Neither bike had carbs on them but they came with a box full of disassembled carbs. I put a set together hoping I would put them on and the thing would fire or even try to run, just to establish a starting point. Well, no fire. No spark. I know I need to go through the timing but before I start on that, I have a question. The electrical system seems to be a bit of a mess. What is the minimum electrical equipment that needs to be functioning properly for this thing just to start? Do I have to worry about brake, clutch, and neutral switches or just ignition and run/off switches and power to the points and coils? Oh yeah, this is my first time messin with bikes. Thanks.

 

[xschris]

Without papers how would you drive them on the road? Looks like you have a big mess of stuff, not worth the time if your not going be able to register them. Any pics to share? by the way welcome!

 

[bikerbob]

I'll worry bout that if I get one of em running. If nothing else it will be good practice for a bike I can title. I'll get pics up when I get some batteries for the camera.

 

[marmite69]

hi bikerbob welcome yes found this site real friendly every one wants to help if only the world politions could be so friendly we could be in a good place.

 

[drewpy]

welcomes to the forum BB!

 

[hammerlo]

Hello and welcome!!

 

[CadXS]

Hey Bob, welcome to the forum

Check here for some good info on how to wire a simple motorcycle harness. By cross checking this to a Haynes or the diagrams posted here you should be able to isolate the components and wiring needed to start your bike.

Having a good, fully charged battery is pretty vital with these bikes and pick yourself up a multimeter for testing (makes life a lot simpler )

If you are having trouble finding the wiring diagram for your model, post up and somebody will scan one and sort you out.

Caddy

 

[bikerbob]

I don't have a battery yet. Is power from a ten amp battery charger enough to fire the ignition system? If not I guess I'll be getting a battery before doing anything else. Thanks.

 

[xschris]

You will need a battery, or you can use a jump pack.

 

[ahale2772]

like xschris said, the charger is a no go, get a battery, and probably a smaller 1-2amp cgarger/maintainer at the same time (10 is too much for a small batt)

welcome to the site!

 

[bikerbob]

Thanks guys, I'm getting a battery. And the charger has a two amp setting for charging. I'll post a pic up soon and let y'all know if the beast fires when I get a battery. Another question, I found a set of carbs from a Suzuki GS650L in running condition for $50. They are Mikuni 32MM. Any chance I can take 2 out of the bank of 4 and bolt them on the xs400? Thanks again fellas.

 

[bcware]

Well, they're probably not going to fit in the carb boots that hold the carbs to the motor, but if you can come up with a solution for that you could probably get just about anything to work. I'd also think about how the throttle cable is going to attach and how just two carbs will be linked together as a pair; they are going to need some custom brackets I would think. Also, you might have to block some fuel channels that lead to the float bowls, but it depends. Someone else might be able to tell you more.

Depending on your fabrication skills it may be more trouble than it is worth.

 

[bikerbob]

I think you're right, I'll leave em be. Gotta get a battery and get this thing sparking then see how the carbs do. Thanks.

 

[bcware]

These carbs are pretty easy to assemble and clean up and since you have a 77/78 like me there are very few gaskets and rubber parts. If you have to replace anything it would probably only be the float needle and seat (the springs inside my needles were going bad and compressing by different amounts causing the floats to move differently); those run about $16 for a pair of both give or take. The critical and expensive parts that need to be intact are the diaphragms; inspect those and make sure there are no holes because they cost something like $80 each, but I have heard of people repairing them.

I have had my carbs apart a dozen times at least in the last month, so feel free to ask anything and I am also happy to take photos beyond what is already available here. If you're working with a manual ask questions before ordering parts because I have found them be unreliable; there is a fair amount of variation in the carbs from year to year.

 

[bikerbob]

Thanks, I'm sure I'll be looking for help when I get back to the carbs.