[First Time]

I have.

They fall in love with them.

[xs400 ignition]

So I've had this bike for two years now, I'm doing a ton of maintenance so it will hopefully be problem free this summer. Mos of this stuff I've never done before so this quite a learning experience for me. Anyways my current problem is that I'm trying to check and adjust the contact points for the ignition but mine looks nothing like it does in the shop manual I have. Does that black piece of plastic need to be removed or is this an electric ignition? Heres a picture, thanks in advance.

http://img546.images.../i/engine1.jpg/

80 and later are electronic ignition.

[XJ handlebar caps?]

Hi all

the temperatures are now above freezing, the snow has gone, and i can once again venture out of my 4x4 back onto the XJ, however, theres just one little problem...

the bolts that hold the handlebars on have little plastic caps that go over them, one of those is missing, the bolt has rusted, it pisses me off imensely and would like to find another plastic cap, but seem unable to find them, anyone know where i can get one?

- Foameh x

Good luck, I've been looking for those for a while if they are the ones I think they are. I believe that the same ones are used on the XS1100 for the handlebar bolts too, and I've not found anyplace I can actually get them.

[prefix]

Not only inline 4 but is it not a transverse shafty too?, not easy to put round a corner, I've had a go

No, the XJR is chain drive, the XS 750, 850 and 1100's are shaft drive. And while there are some strange handling characteristics with the shafties, you can learn to handle them just fine once you know how they will react in a given situation.

[butterfly valve]

thanks for the reply i have done an engine check b4 i tackled the airbox and all is fine (as far as i know since the engine is out of the bike), the engine runs nice with the original airbox and mods, the jetting seems to cope well with the polished head and exhaust in all rev ranges (did many a plug chop) as to ignition timing and advance curve iv looked into the engine (the best i can) and found that the 2004 cbr 125rr engine (which is what iv got) was one of the best carb models in terms of advance curve and performance, hence why i chose it to put into the bike. and i got a good engine with 5000 miles, i took it apart and its been run in well, no scuffs or marks below the piston rings, and clean oil, and there known for there reliability. iv tried looking around for any examples of mods done to the engine and cant seem to find anything on removing the airbox, so it seems to be something new for this engine and i want to try and get it right im also going to put a slightly bigger main jet in once iv got the air filter to work just to make sure its not going to run lean at full revs.

iv always had a problem with over-complicating things its just me lol hence why i posted on the forum cant beat some old school knowledge and experience!

and neversaydie thanks for the link i didnt think of a ball valve! defiantly something to consider! and it was a question to which anyone could reply to, but i couldnt fathom why you wanted to know the dimensions .....now i know lol cheers

iv just read the link you sent JimR.(took me a while to get my head in gear lol) and am now thinking a washer with a certain size hole would do a better job. il have to have a play and see what results i get.

This does seem to be making things overly complex. When removing an airbox (and LOTS of us XS1100 guys have done that) and switching to pod filters, the new system flows more air. As this causes the carb to work differently it changes the fuel/air mix. Just adjust the jet sizes up to provide more fuel, which is a trial and error type of thing and check the plugs after a full throttle run (clean new plugs) and check the color. If their too white, then you need bigger main jets, if to dark, then smaller. Repeat until you get the right color on the plugs and good performance across throttle settings without flat spots. I'm sure someone out there has changed out the intake on one of those engines and has some idea of how much of a change in jets is needed, but if not, I'd start by going up two jet sizes and see how it runs. Gotta put a load on it to test it though, and you will probably have to go up on the idle jet size too, unless you can compensate with the mix adjustment screw.

Trying to get a specific amount of restriction is easy as everyone has said, just create a box or something over the filter and make a hole, and make it bigger till it right (if you don't want to rejet). A good starting point would be to try a hole the same size as the inlet on the stock airbox for the engine, that is likely what's causing most of the restriction with the stock setup.

Just remember, you can't tune the carbs (other than idle) out of the frame/bike, cause to tell what it's doing requires a load.

[hello from the newbie]

Howdy ecrzeric, I've been to sunshiny florida, and live in sunshiny california. Lived in a few rainy places though, including 5 years in germany (3 as an air force brat and 2 in the army) and some time in even worse places (lots and lots of deep snow (you can ride in the rain, but 3 feet of snow is pretty much not happening)) but never made it to england even given how close I was.

I'm still riding pretty much every day, and not gotten more than slightly damp yet, even with no rain gear (just to bug those not riding during the winter).

[xs400 (sohc) carbs]

At least on the American model for 80 the float height is 27.5mm and the floats are supposed to be brass. There is also supposed to be a plug over the idle jets as they pull fuel through the main jets. If it has the stock carbs, they will be Mikuni BS34 III's, which in the U.S. were shared by many other models in 1980, just with different jets and diaphragm springs. The DOHC bikes have a different bowl on them and your supposed to use the clear tube. AFAIK, there is no spec for the 80 carbs outlining the fuel level using the tubes, only the float height setting.

Also, a common problem on these carbs is for the o-ring on the push in needle valve seat to wear out and let fuel leak around them causing the carbs to overflow, if that was not replaced you might want to do that.

[82 xs400 with a funny turn signal]

Well I got the new battery charged and put it on the bike. Got the bike started and started testing the charging system. Hooked up the battery to the multimeter to check the voltage. No matter how high I rev'd it I couldn't get it to go above 13.7volts and it is supposed to be 14.0-14.5. So I figured I start on the alternator because it seems to have a problem(or an adjustment to the voltage regulator screw, but I will check that later).

Checking the leads of the alternator I disconnected the second lead block connector with the three white wires, those were supposed to give me .72ohms. I didn't get that reading and I can't remember now what the exact reading was but I think it was just over 1.0ohms. Now here is the funny part. The main lead is supposed to have 4 wires that are green, green, orange, gray (reading the haynes manual) but I have black, green, blue and yellow (which is also shown in the wiring diagram in the back of the Haynes manual) I guess that I had to take a reading between the black and green wires (the two that come from the alternator, not the neutral switch [blue] and oil switch [yellow]wires)even though the instructions say green, green. I was supposed to get 4ohms but I only got 3.3ohms. This is telling me the alternator has a problem.

So now the questions;

When reading the main lead wires I am checking between the two wires (black + green)coming from the alternator, as in I put a probe on the black and the other probe on the green and read the resistance between them, right? (don't flame me because I am a noob, lol)

Also bike bandit doesn't seem to let me select the alternator parts for ordering, how do I find a new one if it isn't just a loose connection.

To take apart the alternator housing, I guess I should drain the oil first?

Thanks again,

Spark-z

BTW with a fully charged battery the signal keeps flashing with the brake depressed. Funny

Ok, here is the deal, your readings are all in the same range I have found on working charging systems. What I have found, is all these years later, the resistance tends to be just a little off from spec, but this is not saying they are bad, just old. The most common failure is the voltage reg or the rectifier (or combined unit depending on what you have). These can be had off ebay used and good pretty cheaply. Oh, and on the newer models contrary to what the haynes (or clymer for that matter) manual, there is no adjustment on the voltage reg, its solid state and non-adjustable. One test is if you check the wiring diagram, there are two wires to the field coil, one get battery voltage and the other goes to the reg and gets partially to fully grounded to energize the alternator. If you have the bike running and ground the side that goes to the reg you should get an increase in voltage at the battery, if not, then the rectifier may be bad, if the voltage does go up the reg is bad. There is also a test in the manual for the rectifier grid that is pretty simple to do and can rule that out as being bad. What I'm saying here is that your readings on the stator wires and field coil are almost exactly what mine read, and mine works great. When mine wasn't working it was the regulator, quick fix (tough to change though being on the bottom of the battery box.

[removing o-ring fork caps]

they sound like the xs400 forks.

I use the wife to pick out the little circlip with a terminal driver. I push down really hard on the fork cap with a heavy duty screwdriver so she can get to the circlip.

It then flies across the garage and I spend 1/2 hour looking for it.

if the cap won't budge, i nod my head and the wife hits it with a mallet!

That must cause a bit of a headache!

I've managed to get that type out by myself, but I was about ready to throw things before I got it done.

[carburetor options for 81 xs400 and other issues]

My 81 XS400 had electronics: http://cgi.ebay.com/ebaymotors/1981-Yamaha-XS400-special-rectifier_W0QQcmdZViewItemQQhashZitem3ef97eb32cQQitemZ270473802540QQptZMotorcyclesQ5fPartsQ5fAccessories#ht_500wt_956

Mounts around/under the battery. I replaced that and my battery and I have no charging issues any longer.

The holes in the diaphragm will certainly screw things up. The new diaphragms are expensive, so is gambling on whether an ebay special is going to contain a decent set. I'd go by the condition of your carbs in general whether that's a good idea or not.

I haven't seen aftermarket carbs for the XS400, just her larger sisters. MikesXS has a lot of parts that will fit in our carbs without issue: http://www.mikesxs.net/products-35.html#products < was vital while I was rebuilding my carbs.

EXCELLENT overview of the BS34 carbs on our bikes (while some of the specific jet sizing info may be off, in general this guide is amazing): http://drop.io/jn5sqkc

You can use plastidip to fix the diaphragm and it will work pretty well. Otherwise while they are expensive, replacement carbs are going to have old ones too, and once again plastidip may help there.

[Can I get new plug wires for the xs400s at Pep-boys or auto zone?]

Any solid core non-resistance plug wire will work. Just make sure it's not that carbon core resistance crap, that won't work, but any solid core wire works with them as long as it fits into the fittings on the coil. Be glad you have the 400, the 1100 don't have replaceable plug wires, you can manage to replace them (usually) but you have to hack the coils to do it. Most install after market coils instead.

[more power]

hi could some one tell me if the down pipes of an fzr600 will fit on an fzr400 exup. i am hopeing it would give me more power. thanks

Don't matter, even if they fit (which they probably don't) they won't give you any more power.

[Hard start]

intake boots are good, but i will check again as described. I'll try the plugs if for nothing else as something to try. I'm really wondering if my air filter theory is correct, since it might explain the inablility to idle below 2k. If there isn't enough restriction to induce some "pull" on the fuel system to get it going, might that not cause it to behave as it is? I have an old airbox off a Kawasaki KZ400 that i can try and rig up, but the air box to this bike is long gone. If this theory seems to have some merit i'll try and find some more restrictive filters for the bike.

if i'm talking nonsense though please correct me.

Those air boxes (and related parts) are pretty easy to find on ebay. Otherwise, your carbs NEED to be rejetted, as the cone filters WILL affect the running. Unless the idle mix has been adjust properly also (which I guessing it has not) then it won't idle well (or start for that matter). Also, these are pretty much the same carbs as the XS1100's use, and the mantra on the XS11 site is clean the carbs really good, then clean them again, and then clean them again, meaning it generally takes at least 3 times to get them clean the working well. I know I cleaned mine about 6 times before I got them right. I also had to replace the o-ring under the idle mixture screw spring as those flatten out and go away mostly over the years and these things will NOT idle well without that o-ring. That o-ring is available if you look around, but can be a little hard to find. Also, try spraying wd40 at the ends of the throttle rod and if the idle speed changes that means the butterfly seals are shot, you can get those from MikesXS.

It is a LOT of work to get these carbs right, but when they are, it should start easily, I almost never need more than 1/2 choke on mine, and then only for a short time.

[How concerned should i be about these cams?]

I can tell you that a previous owner probably had some oil in it that wasn't quite right. I think they tried to use car oil for a while (i know you aren't supposed to, first thing i did was change it). I forget what brand is in there now, but it is decent bike specific oil. Ran it for maybe 300 miles (2 rides) and changed it again. The valve clearance was adjusted very recently, and he said a few were off, but he didn't mention wear. Looks like i'll be learning how to set the valve clearance myself when i put the new cams in. I'm actually looking forward to it, i haven't torn down an engine in a while, i quite enjoy it. Thanks guys, i always appreciate the help, even if i'm bad at checking back for the answers.

Actually that's one of the biggest points of contention about oil in motorcycles. Frankly from most of the research I have seen, the main issues would be with with non-mc oil would be viscosity loss because it's running through the gears, and clutch slippage because of friction modifiers in the oil. My opinion is that oil for use in diesels will protect properly and most of them don't have the friction modifiers so are probably good there. That said, I can buy MC specific oil for just slightly more than normal oil, so I do just because I want my clutch to not slip. Than again I'm not married to using MC oil, and if they want to much more than for the normal oil, I'll just go with the diesel specific stuff, got over 50,000 on my 400 that way with very little wear, and 80,000 on my old engine in the 1100 (although I had to replace it because the PO ran it with gas in the oil and knackered the bearings.) The replacement engine will always have good clean oil changed regularly though, so I expect it to go in excess of 100,000 miles.

[XS400 No Brake light-running lights work]

Thanks duanage and drewpy! The wire going from the front break lever to the switch is where the problem was-the switch thought the brake was always "on." Mounted the brake light too so I'm pretty much street legal now! Installed the electric relay flasher also but all that does is blow fuses...maybe tommorrow I'll figure that part out.

Did you get a 2 or 3 prong flasher? A 3 prong flasher will NOT work on these bike, you will need a 2 prong, and just plug it in with 2 of the prongs plugged in, if it doesn't come on at all, then try it the other way. The flashers in these things are SPECIAL and are not ordinary automotive flashers.

[Gutted but glad]

Here's another one to the list:

Woman I know of, from a forum I no longer frequent, came off whilst wearing jeans.

We'd all hammered those who don't wear kit, her included. She still chose to rode this way.

Her leg was 'de-gloved'.

In short, the skin all around it was stripped off, as if it were a glove she'd been wearing.

This was a good while ago and I still don't believe she's back on her feet.

By comparison, a friend of mine came off at a mere 15mph.

Due to the circumstances, he lost his leg. He went on to become one of Essex's best Advanced Riding Instructors.

Had a rider on a forum I frequent on this side of the pond that went down involving a semi truck and trailer, and the trailer went over her and the bike. She was wearing full gear, but didn't have the jacket and pants zipped together and it pulled the pants down and de-gloved on leg and partially de-gloved the other. She is still in hospital three months later dealing with skin grafts and physical therapy. The lesson here is it's not good enough to just wear the gear, but you need to wear it correctly with it all fastened together so it doesn't come apart in an accident.

[How not to clean a bike]

WTF Is wrong with people????

You DO NOT clean a chain with your bike running in fuckin gear!!

Chains were used to kill folk in times gone by so a running chain is gonna do a lot of damage to yer hands (as shown in the link!)

Sprockets have TEETH.................TEETH....................Thats TEETH

TEETH BITE

FFS its just plain LAZY - what a fuckwit

Get a fuckin shaft drive.......in fact....stay away from motorcycles altogether, and get something that you cannot do yourself any damage with...... like crayons.....

Well, I don't know. I always do the spraying down with the engine running in gear (400 which has a chain) but never with anything closer to the chain than about 4 inches. Then shut it down and scrub it off, then start it again and spray on the lube. This of course is always after a 15-20 min ride to warm up the chain first. But never never never touch a moving chain. They use the things to cut down trees!.

[gear change.]

your sick . just exept the appoligy and tell me if shortening the lever will work.

I doubt it would work, as you don't seem to have down that shifts need to be firm. If you do a firm full stroke each time (no pun intended here) the shift will work whether its from 1st to 2nd or any other gear. It's not really uncommon for inexperienced riders to have trouble with some shifts (and on occasion even experienced riders can have trouble) but you just need to cultivate the habit of firmly pressing the shift lever till it stops each time (you won't hurt it, it's got stops to protect it).

[Resurrecting a 78 xs 400 thats been sitting for five years]

Oh, you mean the big screw, the really big one...the biggest one on the whole carb. Christ, I am such an amateur...Yeah, gave that a couple of turns and down came the RPM. What can I say, I like to think it was the fumes.

Man, did that feel good though. Still have to tune it in properly but just to not have a screaming idle is really really satisfying right now. Jesus, it feels good. Thank You for that. I wish i could buy you a beer. And that goes to everyone who has helped so far.

How does that screw work though, I saw that it pushes open the throttle valves, does that create greater vacuum to suck up more fuel from the bowl. And how come opening up the valves via the throttle on the handlebars increases the rpm. Whats goin on there, I can read up on the internet I suppose.

That screw controls where the throttle plates sit when you release the throttle. To lower the idle your closing them more, to raise it your opening them. If the idle it too high, the mixture screws won't work right and you can't get the mixture set like it should be. When you get it right, it should idle real nice at 1200 RPM and nice and steady.

[I got my 81 xs400 running WOOO!!!]

Hey guys, I just got my 81 xs400 running YEAAAA. My friend helped me a great deal since he has a xs650 of his own. Anyways I come in need of help. I am trying to find out if the contact breaker cover sits on a gasket. I have a old haynes manual that covers xs 250's or whatnot to 400's so the general pictures looks like it needs a gasket. But when I look at bike bandit and drag up the parts, it does not show a gasket on it. So does it have it for my model or it does not? Also I need a engine bolt for the lower mount, does anyone know if earlier years can fit it? I bought some bolts off ebay and it seems a little short. Do latter years fit? and last but not least I am trying to find a new petcock for the tank, does a 650 petcock work?

No gasket required on that cover. The units that had points under there did, but the electronic ignition models don't use a gasket there.

[79 400 xs..]

SWEET! Thanks J!

I will lookem up in the parts catalog.....

McMunzell

If you go to a low backpressure exhaust and cone filters you WILL have to rejet. And while someone might be able to give you a starting point the only real way to do it is to do plug chops and adjust the jetting.

['running lights'?]

yeah my switch on my 81-xs400 doesn't shut off all the time when you push it in....some times it does. but mostly i push it to the opposite direction. and some times left takes two pushes to stay on. I just figure, Its a old switch, i'll deal with it.

yeah and that self canceling directional are pretty sweet, i was surprised. i know know how they work, black magic? tip censor?

There is a unit under the tank that handles that. With the stock blinker unit the third pin is an enabler and when you push the signal switch to the right or left a signal is sent to the tunr canceler and it enables the flasher, it also has a magnetic reed switch in the speedo that sends it signals so it knows if your moving and approx how fast/far. I'm working on figuring out how to retain auto cancel with an aftermarket flasher so I can use LED bulbs without load equalizers (which defeats the purpose of the LED bulbs which is to lower current draw on a stretched as tight as a drum charging system). But as I was saying, those auto cancel units can go bad, as mine has partially done. When the temps get hot, it stops cancelling, (this is on my 400) and the auto cancel unit seems to be made of unobtainium. So next would be to reverse engineer that unit as well, but I'm not sure it's worth it (the flasher adapter might be as I suspect it's going to be simple to make, but I haven't gotten far enought on it to be sure yet.)

['running lights'?]

Mate of mine has a Honda Nighthawk 550. His indicators are always on.

This is what confused the heck outta me when I first saw it. Apparently it's particular to US bikes and standards may have changed since '83

Yeah, my 75 honda had running lights too. As does my 80 XS1100, but the XS400 doesn't. A lot of the XS line didn't have them, particularly the specials.

[Resurrecting a 78 xs 400 thats been sitting for five years]

You need to start out with the idle mixture screws out about 1 1/2 turns. Then slowly turn them out one carb at a time to highest idle speed (and then adjust the idle speed, there is a knob between the two carbs for that) then turn them down just a bit (it should be slightly lean but not too much). Lean idle will cause it to hang coming back to idle when warm, and if the idle speed is set too high (which it sounds like it is) the mixture screws will have little if any affect, so turn it down with the knob in between the carbs and work your way from there. These things can run very well and idle pretty smooth for a two cylinder with no counter shafts or other vibration reducing devices). I ended up with my mixture screws at about 5 turns out with our crap california gas, but the 80's are known (at least in the U.S.) as being way too lean in stock condition.

[If it ain't one thing. it's another.]

Well that is partly true. They don't stock all the parts even for the 400, and definetely not all the parts for my XS1100. In particular a lot of the less popular rubber parts are no longer available, and some ring sizes etc. I'm starting to consider picking up a couple of parts bikes just to make sure I have parts for the future, or course knowing me I'll fix them up and get them running and then they won't be parts bikes anymore.