81 xs400 needs maintenance, tune up.

Hello all.

I'm new to the forum. I've never rebuilt a motorcycle but have some general knowledge of automotive repair. I'm hoping that with the help of this forum and some research, I can get this thing back on the road. I'm also hoping that this will not require an intensive rebuild because I'm not so sure I'm willing to spend the money on it. Hopefully a tune-up and maybe a few other things will take care of it. A bit of history then: it's an 81 xs400 that has not been driven in several years. My father used to start it yearly and drive it a bit to keep it running, but the last 3 years has seen some neglect, to the point where it's basically sat in the garage. Now last summer, I decided to drain the old gas, give it an oil change and checked that the plugs were ok and had spark and fuel. We couldn't get it started. It's possible that the battery was too weak. He does not keep it trickle charged. It could very well be on it's way out or toast by now. However, we towed it behind a car to attempt a push start, and she started up. It was low on power but it ran. Alas, since that day it's sat in the garage again. This year I would like to get it started and running right. I will say that the low power issue was evidenced in previous years after sitting in winter storage, but after riding around for a bit, the power returned. Maybe this thing just needs to run? Anyway, where do I start this year? He did put in some fuel stabilizer last year, so maybe the gas is still ok. I would like to check the ignition to make sure everything is ok with it. It has an electric start but the button popped out and was lost, so is using a screwdriver in place of the button ok? It seems to work. I can stick with the kick start also. I would appreciate any help. I did download the manuals but thought to check here first. Sorry for the long post. Thanks in advance.
Let's bring this old girl back to life!

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Thought I would post a picture. It has barely 11,000 original kms( 6,800 miles)! My dad has thought of scrapping it. What a shame, I think.

Alright guys, I guess the first step is to make sure I have a good battery. I took a voltmeter across the 2 terminals and got a ready of 12.1. I know this doesn't really tell me if the battery is good. Fluid level was on the low side for 4 cells so I topped it up a bit. I'm ready to try to charge it. I have a battery charger capable of outputting 2amps and a battery tender which puts out 1amp. Which should I use and for how long?

A new battery is a good place to start but you can try charging up the one you have with the 2 amp charger for a few hours first. Also, in general after sitting several years the carbs need a VERY thorough cleaning. After cleaning the carbs ALWAYS install an inline filter to keep any rust/crud from the tank from fouling up the carbs again. Change the oil, replace the plugs, check and adjust the timing if necessary and its likely it will run reasonably well. However, with any 30 year old bike you should thoroughly inspect/adjust/replace the safety systems before riding: lights, turn signals, stop light, both tires, rear brake shoes, front brake shoes. I see you have front drums so there is no master cylinder or caliper to worry about.

Thanks for the info. I plan on removing the carbs in the next couple of days and will report back on their condition. Will any old inline fuel filter do, or is a specific one recommended? Also, is it correct that initially a fully charged motorcycle battery should read around 13.4 v and then settle at around 12.6v? I want to be careful not to overcharge the battery.

Alright, so I removed the carbs and gave them a clean but I was unable to remove the pilot jets. Looks like the tops had been previously stripped. There really wasn't much gunk at all in the carbs, so hopefully I can get away without having to remove those jets. I do have some questions. The pilot air jets; there's no adjustment here correct? They just screw all the way in? Also, the floats; when they sit right side up they actually drop lower, but measurements are taken while they are upside down?

This is my first time disassembling a carb. Thanks for the help.

I only know about in-line filters, thanks to Petei's how-to thread. It's cheap and easy to follow the thread:
I want to avoid boiling my carbs in lemon juice for as long as possible so was glad to find Petei's thread the first week I owned the bike.
So far, it has kept my carbs working like the day I got the bike. Best of luck and don't let your Dad scrap something so new and unspoiled (not without PM'ing me first).

I set the idle mixture 3 turns out as recommended here although the service manual says 1 1/4 turns. Also, the float height had me confused. You guys speak of 32mm but I believe that's for the brass floats? I have plastic ones and they are both set at 22mm. Given the mileage on the bike I don't believe they've ever been messed with. I'm convinced it came 22mm from factory. Everything in the carb looked pretty pristine, given the age of the bike. So is 22 mm correct? I can't set it to 32mm even if I wanted to. Even 26 mm seems far off.

Well, my first attempt at starting the bike was unsuccessful. Here is a list of things I've done so far:
1. Charged battery
2. Old fuel removed and replaced with fresh fuel.
3. Installed fuel filter
4. Cleaned carbs (unable to remove pilot jets because the heads were stripped, but everything looked pretty pristine so hopefully I'm ok)
5. Set Idle mixture to 3 turns out and checked float height (22mm with plastic floats)
6. Reconditioned air filters with new foam.
7. New spark plugs gapped at approx .029 in
8. Repaired starter switch/button (had fallen out)
9. Checked resistance of ignition coils (both good)

I also took my battery in to get tested just to be sure it was good.
Readings for battery:
107 CCA
Voltage: 12.58
AMP Hours: 1.2
It tested good apparently.
I'll need to pull the plugs out and confirm I absolutely have spark and will check the resistance of the ignition pick up. The plug wires looked ok on visual inspection but could be they need replacing. The fuses look ok but I'm going to clean them nicely as well as the contacts in the fuse box. Anything else I want to check? I guess I should also try the kick start? Do I bother checking the regulator and rectifier at this point or would those be charging system related and can be ignored for now?
Thanks guys. Really hoping to get her running soon.

SHE LIVES, by Jove SHE LIVES!
I couldn't resist stopping by my Dad's after work yesterday even though I'd probably only have 15 mins to work on the old gal. I knew she had fuel, I knew I had a good battery, and after pulling the plugs I knew I had a strong spark. So what gives I thought? I cleaned the fuses and connections just in case, which led me to solve the problem with the turn signals, as the fuse came apart in my hand. Well the electric starter just didn't have enough "umph" to fire up the bike after being stopped for so long. So behold, out comes the kick start, and with one pull she fires right up! I had a smile from ear to ear. I was as happy as a schoolboy looking up a girl's skirt for the first time. Yes sir, her growl was telling me "You're lucky you're the one on top!". Hell, I'm not even sure what that means. Man was it music to my ears.
Thanks everyone, that was a hell of a lot of fun.

xs400newbie said:

SHE LIVES, by Jove SHE LIVES! ... with one pull she fires right up! ...

Click to expand...

Hey! Congrats Newb! I guess your Dad won't be selling to me for scrap value now, huh?
Sorry I couldn't help with the getting it going part - that seems to have involved electrics, not something with which I am very familiar. I know the in-line fuel filter will pay off though, especially if the first few tanks of gas dislodge any tiny particles and carry them towards your carbs' orifices.

Now the job becomes breaking it in again without breaking anything or prematurely wearing anything out. From reading on this forum I would conclude that a few simple things could give you lots of miles without any expensive repairs or replacements:

• lubricate the insides of all the cables,
• spray all electrical connections with the electrical connection spray stuff,
• change the oil and oil filter and oil screen,
• check the tire date codes to make sure they are young enough to use and check for checking,
• a little Rust-check on any frame welds etc. where the paint isn't perfect

Happy motoring!

xs400newbie said:

the fuse came apart in my hand. Well the electric starter just didn't have enough "umph" to fire up the bike after being stopped for so long.

Click to expand...

The starter is probably also a fuse problem. It runs through the fuse labeled "IGN". If the clips are loose there will be too much resistance.

This will solve most of your electrical woes:

http://www.oreillyauto.com/site/c/d...7_-1_-1&keyword=fuse+block&pt=N1177&ppt=C0172


Littelfuse Blister Pack - Fuse Block
Part Number: 350418BP
UPC: 79458035193
ATO Fuse Block
Bottom Mount

It would have definitely been a shame to scrap it, it's a pretty bike. Congrats on all the work, and I hope you have many happy hours in the saddle.

P.s. I am just west of Toronto (Milton), and have put on a happy 2000 kms this year with my new baby, but I"m already thinking of selling her, and upgrading. I want forward pegs, and a softer ride.
My mechanic put in new brakes (front and rear), used but good caliper, (have a rebuilt kit on standby), new plugs, oil changed, and fresh fuel when I bought it in May. Been riding it regularly since.