How-to: What to do first with your new XS400

willem

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Since there are always a lot of questions and things to be done when you newly acquire and old XS400, I'd like to provide everyone with a step-by-step guide. Please comment, provide corrections or suggestions.

OK, so you've got yourself a XS400. Welcome to the forum, and welcome to one of the most helpful communities I know. There are a few things you'll need to do first. Before anything else, get the manual for your model HERE. A nice overview of the helpful threads on this site can be found here.

If you run into any problems on the way, don't hesitate to ask here on the forum. Also, the google custom search function and advanced forum search are pretty good. The amount of stars next to the subject is a rough indication on how difficult the jobs are. The more stars, the higher difficulty.

0. Bike identification *
Before anything, find out if you have a DOHC or SOHC model bike, as the bikes are very similar in many ways but have distinct differences when it comes to a number of jobs. Also, parts are usually not interchangeable so keep an eye on compatibility when you order anything.
If your bike says "Maxim", "Seca", "DOHC" or "YICS" anywhere, it's likely to be a DOHC bike. These are the later model XS400 (1982-1989), of which the Seca has 6 gears instead of 5. Both the Maxim and Seca have (unless limited due to local laws and regulations) slightly more hp than the earlier XS400's. If your bike does not have any of these marks, it's likely to be a SOHC (1975-1982). If it says "Special" anywhere, it's definitely a SOHC. Of course, there has been endless modding and chopping on a lot of these bikes, so if you really want to know for sure, post some pictures on the forum and we'll help you ID your bike.
Further info on the different models of XS400's can be found here

1. Visually inspect the bike **
Before riding anywhere, whether you're looking at buying the bike from someone or you just pulled it out of a shed somewhere, check it. Use the inspections section of the manual to help you find what you're looking for. Here's the list:
- Do the tires look cracked (old rubber), is there at least 1 mm of thread still on them?
- Is the chain flexible, well-adjusted and greased?
- Is the rear brake shoe worn to the limit?
- How far are the front brake pads worn?
- Look under the seat. How are the wires doing? Use your common sense, if it's rusty and horrible, you'll know the bike is poorly maintained.
- Look under the engine for oil spills, look on the engine for drips. Some leaks may be slow, but persistent. An oily sidestand is usually indicative of leaks from clutch rod seal and/or main shaft seal.
- Look for obvious flaws, like holes in the exhaust, serious rust and things that are put together with duct tape, zipties and wire.
- Check the oil level of the bike (instructions here)
- Look for any dangerous aspects, like center- or sidestand springs missing, cables that are way too long, etc etc. Use common sense.
- Have a feel around the levers and cables on the handlebars. Clutch, choke, throttle and brake cables should feel solid and smooth, and all but the choke should spring back.
- Check if both brakes are working
- Check if the clutch works by putting it in gear and pushing the bike, with the clutch in it should be fine, without it you should have a hard time pushing it through the compression (in 1st gear, that is).
- Check the teeth of your sprockets. They should be a bit pointy (not rounded off) and should definitely not look like shark fins or waves (asymmetric is bad). Yank on the chain at the far rear of your bike (halfway the rear sprocket). The chain should not come off the sprocket more than half an inch. If it does, the chain is stretched to the limit.
- Check if there is fuel in the tank. If it's older than 2 months, drain it and put in fresh fuel (get non-ethanol fuel if you can, ethanol deteriorates the rubber boots and seals on our bikes).
- Check for free play on any of the bearings. Push the front wheel against a wall to check the steering head for free play. Yank sideways on the wheels, just check if everything is solid. You don't want to realize your rear wheel is loose when going 80 mph on the freeway.
- Check the rubber intake boots. Weathered and cracked ones likely mean they leak and the bike won't idle right until they are replaced. Intake boots that are covered in silicone, gasket sealant, or anything else, are likely cracked under all that gunk and leaking. Also look for broken bolts and missing/loose/broken clamps, cracked/missing vacuum hose to the petcock, cracked/missing vacuum cap on the right intake vacuum port. All of this will mess with air/fuel mixture in unpredictable ways and make the bike not run right.
- Check the brake hoses for damage and weathering. On OE rubber hoses look for a little plastic ring - it has manufacture date stamped in it. Some hoses have the date printed on them. Yamaha says brake hoses are good for 4 years from date of manufacture. Yours have likely been there for 35. Consider replacing them even if they don't have obvious damage, they can rot on the inside.


2. Electrics *
Put the key in, turn on the ignition and check the electrics. If it's a barn find, you might want to replace and/or charge the battery before hand either way.
- Did the oil indicator light go on for a second?
- Does the neutral indicator light work?
- Do the headlight and tail light work?
- Does the high beam work (both switches, signal light and high/low beam)?
- Does the brake light work on both brakes?
- Do the turn signals work?
- Does the horn work?
- Take out the spark plugs and have a look. Here's how you 'read' plugs. Put some new ones in, regardless of what the old ones look like.
- Check the fusebox, or, better yet, replace it with a modern ATO/ATC blade fuse box. The clips in the old Yamaha fuseboxes get brittle, which makes them lose contact or break, causing weird electrical issues and potentially stranding you on the side of the road.

3. Give it a try *
Try to start. Make sure the killswitch is not on, that won't help. Try the electric starter (if you have one) first. If it runs, do a happy dance and go for a little ride. If not (or it barely runs and stalls), continue at 4. If it doesn't even turn over on the electric starter, measure the battery voltage and troubleshoot from there. Search/post on the forum for more help, and look in your manual. In any case, continue at 4.

4. Carburetors **
Watch these videos. Take off the carbs and clean them. Unless the PO is on the forum and knows what he/she is doing, they're most likely dirty. These infamous carbs are the biggest cause of problems on these bikes, every XS400 owner has had to deal with dirty carbs at one point. Here is another handy post on cleaning. Even if your bike is running, it's a good idea to clean them. 9 out of 10 bikes on this forum which are not running, running poorly, have starting issues, or stall sometimes, can be fixed by cleaning the carbs.
Here is an exploded view of some '79 and earlier carbs, to help put everything back together.

5. Fuel filter *
Install one. Seriously. And install it the right side up. Find out how here. It'll keep your carbs out of trouble for a long long time, and for $3 and 5 minutes work you'll regret it if you don't.

6. Engine oil change *
Do one. Even if the PO says he changed it last week, you can't be sure enough with oil. Take out the oil filter too and change that. Put in something like 10W40 motorcycle oil, just make sure it's suited for wet clutches. Read about oil changing here and about different oils to use here. In short, the 20w40 (SOHC engines) or 10w30 (DOHC engines) recommended in the manual is fine, but since these bikes were made there have been newer and better oils developed. Make sure you don't over torque the oil filter bolt, use a torque wrench if you can. This goes for a lot of other bolts as well, but the oil filter bolt has been notorious for being made of butter.

7. Air filter *
SOHC bikes have two filters, one under each side cover. Check them. They are oiled foam type. If the foam is good, wash and re-oil. If the foam is rotted, replace or re-foam the filter. UNI sells foam in sheets. This is especially important for barn bikes where it is likely disintegrated, you don't want the chunks gumming up carburetors.
DOHC bikes: Open the air filter box (left side under the side panel) and inspect it. Clean out the critters, crabs and spiders by blowing air through it. If that doesn't seem to get it clean, replace it.

8. Front fork oil change *
Follow the manual for this. You can use the recommended 10w30 for it (what the manual says) but nowadays there are all sorts of options for front fork specific oil. I used a 10W front fork oil by Eurol.



CONTINUE ON NEXT POST
 
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nice one Willem but you need to differentiate between dohc and sohc bikes or it will get confusing.

oil for sohc bike is recommended 20w 50 for instance
 
9. Brake fluid change **
Again, use the manual. If the brake fluid looks squeeky clean, clear and colorless, just bleed the brake.

10. Clutch adjustment *
Adjust the clutch. It takes 10 minutes, and is often neglected. Follow the manual. A bike that has been sitting a while might have its clutch stuck together. Pulling the lever and rolling it back and forth a few times should get it unstuck.

11. Valve clearance **/***
If you've got an SOHC model, praise yourself lucky. The SOHC engine has adjusters on the valves, which makes for a much easier job. Valve clearances on SOHC engines take 15 minutes to do - check and adjust per manual. Your engine will thank you. You only need a couple of wrenches, a feeler gauge and a Phillips screwdriver. Mind the valve covers - the threads are thin, and if you wreck one they can be hard to find. Here's a how-to for checking the SOHC valve clearance.
On the DOHC we're getting to the more advanced stuff. Here bentwrench describes nicely how to do valve clearances yourself. Use the manual for specs on the shim sizes. Using shims to adjust the valves may seem like a bad design, but the shims actually make for a much more stable valve clearance setting. Adjustment will be needed less often than on the SOHC bikes.

12. Carb sync **
Get a manometer (or build one yourself for cheaps) and follow the manual. This will fine-tune your carbs. Don't expect worlds of difference, just a smoother running ride. The simplest manometer you can make is just using one tube, about 10 feet long. Get a see-through tube which you can attach to your vacuum ports on your carburetor intake boots on both sides and make a U-shape. Put a little oil (about 1/3) of any kind into the tube, hook up the tube to the vacuum ports and start your bike. Be careful because it will want to suck the oil into your carbs, which is bad. Turn the bike off before that happens. Adjust the sync screw until it doesn't suck oil out of either side of the U anymore: that's when your carbs are balanced :) Try to use the biggest diameter tube you can, while still being able to attach it properly (air tight) to the vacuum ports (use zip ties or something). If the tube is too thin, you'll get air bubbles in the oil and you'll never be able to sync well.

After syncing your carbs, set your idle mixture screws

13. Lube up *
Grease the chain, make sure all moving parts are greased well. It'll keep your bike in tip top shape. Repeat this regularly.

14. Service the swingarm bearing *
Use the manual to find out how to tackle this. The swingarm bearing is a weak spot on the bike, and because it is often overlooked (and therefore never greased) it tends to rust into place. It'll start eating out the inner workings of the bearing, which in the end leaves you with irreparable damage to your bike. So open it up, grease the hell out of it if it still looks OK, but you'll likely have to replace some bushings.

15. Points ignition * -Only for early SOHC bikes
On early SOHC bikes - check ignition points. Make sure they are not broken and corrosion-free, gap them as per manual.

16. Enjoy *
For now, you're done. Ride like the wind, and get to know your XS before starting with any modifications. At least make it run (well) before starting to do chopping and modding. Don't forget to introduce yourself to everyone here if you're new, and post pictures of your new bike. A lot of well-respected and knowledgeable folks here will start accusing you of not owning an XS400 if you don't.

* Extra tips & Tricks *
- When making a turn or u-turn, look towards where you'll want to end up. Your bike will follow, even if the turn is really tight.
- Assume you're invisible in traffic. Especially to people driving cars. Try to assume they're going to sway side to side, brake hard out of nowhere or turn without signaling. Basically don't trust anyone. When riding behind a van or truck, try to stay on the side of your lane so you can still see their drivers' side mirror. This way you have a chance to be seen. If you're riding past parallel parked cars, assume they're going to open car doors or take off at any second. Keep your distance.
- Use your motorcycle agility to your advantage. You're nimble on a bike, cars are sluggish. Don't stay hanging behind a truck, just overtake it. Try to find the nicest free space in traffic, and get out of there when you feel like you're getting squashed in between two cars.
- Try to stay away from riding behind trucks, loaded pickups, vans, anything with something strapped to the roof and bigger vehicles which block your view. Having an overview and knowing what's coming is very important on a bike. Imagine riding right behind a truck, and there's a big pothole. Even if the truck takes it full on, it'll be fine. You'll crash if you get your front wheel stuck.
- Try to steer clear of any markings on the road (the white lines and arrows), sewer covers, fallen leaves and road repair lines, especially when it's wet. These things are much more slippery than just good ol' asphalt.
- When riding with a backpack on, don't put in any sharp objects like screwdrivers. Imagine falling off the bike and sticking this object in your back, that's not pretty. If you do want to carry something like that, put a hard piece of plastic, a book or a folder on your backside so you can't get stabbed. Also, disc brake locks can cause serious back pains if you fall on them when theyre in your backpack.
- Follow the AGATT principle. This means All Gear All The Time. Get some good stuff: helmet, jacket, pants, gloves, boots. Get perforated leathers if you're in a warm area. Just spend the extra $$, this is money well spent I can tell you that.
 
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Fantastic job Willem. Now we can credit you anytime we blow off a poor, frightened newbie . . . :wink2:
Glad you edited #6 for Drewpy. Just so it doesn't look like we think the whole world revolves around dohcs (maybe we do, maybe we don't), you might want to edit #11 to note that sohcs don't have shims but adjusters.
 
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There are a few things I think this FAQ needs added. It's missing a bunch of things applicable to SOHC bikes.

Visual inspection:

Check the rubber intake boots. Weathered and cracked ones likely mean they leak and the bike won't idle right until they are replaced. Intake boots covered in silicone, gasket sealant, or anything else, likely are cracked under all that gunk and leaking anyway. Also look for broken bolts and missing/loose/broken clamps, cracked/missing vacuum hose to the petcock, cracked/missing vacuum cap on the right intake vacuum port. All of this will mess with air/fuel mixture in unpredictable ways and make the bike not run right.

Check the brake hoses for damage and weathering. On OE rubber hoses look for a little plastic ring - it has manufacture date stamped in it. Some hoses have the date printed on them. Yamaha says brake hoses are good for 4 years from date of manufacture. Yours have likely been there for 35. Consider replacing them even if they don't have obvious damage, they can rot on the inside.

Check for oil leaks. Some leaks may be slow, but persistent. An oily sidestand is usually indicative of leaks from clutch rod seal and/or main shaft seal.

Adjust the clutch. It takes 10 minutes, and is often neglected. Follow the manual.

A bike that has been sitting a while might have it's clutch stuck together. Pulling the lever and rolling it back and forth a few times should get it unstuck.

Valve clearances on SOHC engines take 15 minutes to do - check and adjust per manual. Your engine will thank you. You only need a couple of wrenches, a feeler gauge and a Phillips screwdriver. Mind the valve covers - the threads are thin, and if you wreck one they can be hard to find.

On early SOHC bikes - check ignition points. Make sure they are not broken and corrosion-free.

Air filter - SOHC bikes have two filters, one under each side cover. Check them. They are oiled foam type. If the foam is good, wash and re-oil. If the foam is rotted, replace or re-foam the filter. UNI sells foam in sheets. This is especially important for barn bikes where it is likely disintegrated, you don't want the chunks gumming up carburetors.

Electrics - fuse box. Check the fusebox, or, better yet, replace it with a modern ATO/ATC blade fuse box. The clips in the old Yamaha fuseboxes get brittle, which makes them lose contact or break, causing weird electrical issues and potentially stranding you on the side of the road.
 
non ethanol fuel?

That may or may not be available, depending on where you live.

Ethanol absorbs water from the air, which can rust your tank and some stuff inside the carburetors. Usually a problem with bikes that sit, more so than the bikes that get ridden a lot.

It will also make rubber components of the fuel system wear out a little faster.
 
Updated! unfortunately it's a bit too long for one post now.. Thanks for the input and keep it coming! :)
 
Not sure if this should be here but do not over torque the oil filter bolt it is made of butter and will round off next time you want to undo it.

Posted via Mobile
 
Not sure if this should be here but do not over torque the oil filter bolt it is made of butter and will round off next time you want to undo it.

The oil filter and bolt are the same as the XJ series bikes. You can buy a replacement oil filter bolt that has a larger and sturdier head - I got one for my XJ from XJ4Ever.
 
I'd also like to offer an important bit of advice to modders, especially beginners:

MAKE SURE THE BIKE RUNS FIRST.

Nothing sucks more than putting in six months of body and frame work into that pretty little cafe racer just to find out you have a hole in the piston, a spun bearing, or some other hideousness that requires a total engine rebuild.

This goes double for mods involving anything affecting engine tune, such as intakes and exhausts. If your bike runs like crap with stock intakes, switching to pods will not fix it, it will only give you two problems to solve instead of one.
 
The oil filter and bolt are the same as the XJ series bikes. You can buy a replacement oil filter bolt that has a larger and sturdier head - I got one for my XJ from XJ4Ever.

putting in a larger bolt will increase the chance of over torquing and ruining the thread on the oil filter cover, instead of the bolt itself. Better to stick with a buttery bolt which is replaceable I'd say...
 
putting in a larger bolt will increase the chance of over torquing and ruining the thread on the oil filter cover, instead of the bolt itself. Better to stick with a buttery bolt which is replaceable I'd say...
Interesting point. I can certainly attest to how expensive and how difficult it is to find a replacement cover if you over torque. :banghead:
For the price of the bolt I bought that little set of sockets, each with the 6 little moving cams, which will grip rounded bolts no problem.
I thought about buying a new bolt after it was over and done and decided on a tank of gas instead ... :wink2:
 
Interesting point. I can certainly attest to how expensive and how difficult it is to find a replacement cover if you over torque. :banghead:
For the price of the bolt I bought that little set of sockets, each with the 6 little moving cams, which will grip rounded bolts no problem.
I thought about buying a new bolt after it was over and done and decided on a tank of gas instead ... :wink2:

Im with you Lou. I cracked my cover, but after a couple of weeks of searching I got my hands on one. Mind you it was very expensive, and then I saw one on Ebay for 10.99+shipping. I snagged it up just in case, and I already resold it to another forum member.

The cover is very brittle on the dohc and will easily crack with to much torque.:thumbsup:
 
Hi guys, I've got a Japan made XS400 80 model, but I can't figure which exact XS400 it may be. Can alone help me? On the engine it has a imprint of 5E8-000115
 
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