OllieB
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Posts posted by OllieB
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I think you will find that IRC are pretty good tyres we do not het em in the uk they used to coma as standard on some small jap bikes in the seventies and where rubbish then, but all reports i have heard recently say they are good now,
Yamahead is the guy too ask
Mervin,
Thanks!
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Anyone have any experience with "IRC" brand tires? Will replace my mismatched Chinese tires this Spring with a new set of cruisers. Want to keep the same replacement size as currently on the bike and as recommended by Yamaha: Front-100/90x18, Rear-120/90x16. Checking around I find it very difficult here in the U.S. to find both sizes in the same brand tire. I thought I saw them listed for Shinko a while back but not now. Did find the IRC brand in both sizes at Motorcycle Superstore for $77 each with free S&H. Not as low a price as I wanted but probably not that much more since the S&H is free.
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removing the carbs for the winter? The XS400 is hanging out in the unheated garage all winter. What do you guys thing?
Remember, it's bloody cold here in MN.
Stabil or Sea Foam in the gas will do the trick. Not certain there is any gain to removing the carbs and placing them in a heated area. Either treat the gas or run dry as Drewpy does. You have done the most important thing by removing the bike from the elements. If you get a moderate day now and then, start it up. Keeping a battery tender connected to the battery is probably more important.
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The father of a girl I went to High School with was really big on 2 stroke Saabs. Oh my goodness, that was almost 50 years ago!!
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yesterday I finished the fork renovation. The old rusty stansions are replaced by a set of nos's. New oilseals, forkoil etc. Maybe in the future I'll replace the springs by some progressive ones. Has anyone experiece with them? The forkboots are SR500 types from Kedo.com
Although I was very carefull I scrathed my headlamp housing.
I was curious how the (new) headlight of my SR500 would look, so I put it in place to see. It will never leave there
In my opinion it looks realy good and it gives a lot more Lux
I'm not too worried about the extra power the bulb asks, because I have a LED taillight and this new headlamp hasn't got a small 5 Watt bulb in it.
And here's a small impression of the current wire-wheel situation.
The hubs look as new after a treadment with glasspearls, the rear hub has new bearings, front bearings were OK.
The rims are aloy highshoulder ("hoogschouder" we call them in Holland).
If you can't see the spokes your monitorsettings are wrong
I think the red spoked you show look really good!!
BTW, great job so far. -
Not sure if it the same as the RD fuse box but for £20 THIS is a good item
That's what I did with my XS400. It's a nice product. Using the 4 fuse block in the original case does keep things looking original, though. Other methods that seal in the fuse are probably better as they will stop acid fume deterioration (if battery not vented properly) or effects of moisture.
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I am not affiliated with this seller in any way other than I did buy my '80 XS400 from him. Not trying to promote his sale - just thought folks on this forum would find this listing interesting. Hope I am not breaking any rules. If so, please remove or move to the proper place.
Update:
This bike sold for $2002.17 U.S.
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I also got a replacement (used) fuse box (without lid) with the cable and connector that goes.....who knows where lol. Exact same as what I already have but in much better condition. Do you have pictures of what you did?
Don't have any pics. I did not do the replacement, that was done by the P.O. All I did was replace the bad condition fuse box with a new repro. This (http://www.autozone.com/autozone/accessories/Bussmann-30-Amps-rating-black-in-line-SFE-fuse-holder-for-1-4-in-x-1-1-4-in-fuses/_/N-25gq?counter=3&filterByKeyWord=fuse+holder&fromString=search&itemIdentifier=32422_0_0_) is the type of fuse holder the P.O. installed. Some folks use this (http://www.autozone.com/autozone/accessories/Bussmann-30-Amps-maximum-heavy-duty-in-line-ATC-fuse-holder-with-cover/_/N-25gq?counter=1&filterByKeyWord=fuse+holder&fromString=search&itemIdentifier=32415_0_0_) type for the newer style fuses. Since I have never seen a stock fuse box setup, I really don't know how/what the connector looks like. My son's '80 also had the fuse box replaced with individual fuse holders by a P.O.
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My battery still has it's hose and it is vented properly down to the bottom of the bike. I am going to a salvage place at lunch today and hopefully they will have something for me otherwise off to 'The Source by Circuit City'. My fuse box is original as well and I would like to keep it that way if I can. We will see.
The salvage place I am going to closes after today for the whole winter
They were becoming my friends I was there so much lol j/k. They do have my new air filters though. That is the main reason for going today.Good news about the battery vent.
You might also rebuild the original fuse box. IIRC, there has been discussion on this forum regarding such. In any case, you need to do something or your electrics won't be reliable. When you look down on my repro box, the bike looks stock - you just can't see the 4 individual fuse holders below the box. At first, I too was going to replace the newer fuse holders and restore power to the box but I now believe the setup I have makes the bike more reliable and still appears stock to the casual observer. An open-to-the-elements old style fuse holder is just not good for that location.
Glad you located some air filters!!
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I am back. I discovered that the turn signal went solid when I depressed the brake so I am thinking that there are crossed wires somewhere, but let's keep in mind that I know nothing. So I finally unpacked from my move and found my Haynes book so I was going to start looking for the problem this weekend but then something horrible happened this week. The bike went right dead. The pilot box would not even light up when in neutral and the brake lights would not come on and of course the bike won't start.
The first thing I did was take a reading of the battery. It showed 9volts. Then I watched some YouTube videos to learn how to use all the multimeter functions and checked it again the next day and got a reading of 1V. It was draining on it's own and fast. I checked the fuse box and the main line fuse clip was very eroded and fragile. So I was thinking okay that will need replacing but I started playing around some more and discovered there is still continuity through that clip (this is with the key in the off position, should that happen?). The voltage on both sides of the clip is steady at 1V. So I thought it would have been the fuse since there was no power getting to the lights but the fuse (and all other fuses) is fine and the continuity is fine. I am thinking there is a short between the battery and the fuse box and that is why the battery is draining but how do I explain the lights not working even when there was 9V?
What do you all think?
Thanks again.
p.s. I don't want to take it to a mechanic, not because of cost, but because I want to learn. I enjoy the challenge and the help I get
Kind of difficult to diagnose w/o being there. The fuse box is a known issue. The metal tangs that hold the fuses in place corrode and become quite brittle - to the point where, when you move them a little, they break off. Often the cause is battery acid fumes venting right onto the box area because the battery vent tube went missing or became detached from the battery vent nipple. Make certain you have a vent hose and that it is connected. The hose should drop down to just below the frame, keeping the fumes away from anything delicate. This bike has 4 fuses. The amp value of each fuse should be moulded into the box top or printed on a label. Many folks remove the original fuse box and solder in 4 fuse holders. There are different types out there. My bike still uses the original type glass fuses but they are inside weatherproof screw top holders. Others use the newer style fuse with holders that have plastic or rubber caps that keep the weather out. I bought a repro fuse box and screwed it in place (for the original look) and left the newer screw cap fuse holders under the box. Get rid of the old box now as it may be the cause of some or all of your electrical gremlins. One step at a time. Don't fret, you will end up with a nice, reliable bike as well as learn how it works and how to maintain it.
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I have an 81 XS400 Heritage that I hardtailed and bobbed.
I am wondering if there is another alternative to the stock 33mm forks and wheel on my XS400. I want to put a spoked front wheel with drum brake on the bike instead of the heritage special mag wheel and rotor. Either want to find a wheel assembly that will work with the current forks, or better yet, a fork and wheel assembly that will fit in the triple tree clamps. I don't need the speedo. I can get a new axle machined with spacers if it is close to the proper width.
Any ideas? For instance, I know that the old CB350 and others had 33mm forks.
Your profile does not show where you are located - that would help. My son has an '81 XS400 Special II with original wire wheels and drum brakes front and back. Not familiar with the Heritage so I don't know if that will work for you.
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For the Headlight, pull the headlight out & clean the contacts,
then use that 99cent electrical connection goop they sell at the counter at AutoZone/etc.
Also, the headlight will yellow/cloud over the years, may be time for a nice new replacement.
Open the speedo and replace the bulb. It's pretty easy.
Again, clean the bulb casing & then use the goop.
HBI may need a new bulb as well, open the casing and check it. Again, it's not difficult.
It's good to replace ALL bulbs periodically. It's kind of like buying a used rifle...
First thing you do, clean it meticulously, then oil/grease where needed.
Second thing, replace all parts known to fail regularly...(especially bulbs & hoses).
Third, new Brakes, Chain/Sprockets & Tires. Adjust rear tire properly.
Fourth...ALWAYS have a spare starter motor on hand...this is NOT an item to skip when you have a Yamaha.
It will die, sooner or later, and you will need a replacement.
When it dies, slap the new one in, and at your lesiure, have the old one rebuilt at a local shop.
Fifth, always have a spare set of tune-up gear handy...and do one after getting the bike. Plugs, wires, points/condenser/etc.
Sixth...if at all possible, replace the points/condenser setup with Electronic Ignition...
saves you pulling out your hair
But keep the old setup, in case of major sunflares/EMP attack.Great thing is, once you do the total PM, it'll give you YEARS of easy riding with little maintenance headaches.
My Wifey's 1981 XS400 Special II
No points or condenser in his bike - starting with 1980 the XS400 had solid state ignition.
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Thanks you very much. I have done some browsing before I posted anything, I just didn't go back really far. I will get to work on those suggestion as soon as I have a day off from work. Thank you.
No, the inside of the gas tank isn't rusty at all. I know the intake manifold should be replaced asap, it does seem to be dry rotting. I've heard you can fill it with silicon as a temp fix....How long would this last before it became an issue?
And @HoughMade Yeah you're right. It's much better of a size for me haha. My friend are all like 5'10 through 6'5 and they make this bike seem so tiny.
The only reason it's even slightly a concern for me is I do alot of taxiing friends around lol.
Again, thank you all for your time.
I never tried the solicon method on the intake manifolds so can't comment on how that goes. If you do this as a temp measure, be certain to clean off the rubber thoroughly so the silicon will adhere. May work for a while but it is much better to replace them. A set will come with new gaskets.
You are in good shape if the tank is clean inside. Like I said, could be a clogged cap vent or gas tap filter. Did you disconnect the hose from the carb to see if gas runs out while the engine is shut off? If it does, the gas tap needs rebuilding since it is vacuum operated and should not allow gas flow when the engine is shut down. When replacing spark plugs, get the proper non-resistor NGK plugs as well as new plug boots for the ends of the ignition wires. The boots should be 5K or 10K resistance (ohm) value. Got mine from my local Yammy dealer but you may find them elsewhere cheaper.
If the factory plugs are still covering the idle mix screws, you will have to drill them out - best done while carbs are removed for manifold replacement Not difficult but drill slowly with a bitt just slightly smaller than the opening. Once removed, access to the screw is easy. If the small o-ring doesn't come out with the screw, look carefully down inside the opening for it and fish it out. Replacement of these o-rings really does solve stable idle speed and low rpm performance issues.
Here is a link to another place where you can get reasonably priced replacement air filters for our bikes:
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Hey guys, I'm new here.
I bought an 81 XS400 Special off of craigslist a few weeks ago and been having a ball with it so far. Unfortunatly I'm rather short (5'3) and cannot flatfoot the bike.
I wanted to know if anyone could give me ideas for lowering the bike anywhere from 1 inch to 2 and 1/2 inches? The shocks are already set at the lowest setting (the stock ones I believe)
Also, I've noticed some issues I've had, and I'm just learning about mechanics so I don't know fully how to address them on my own without just taking it to a shop. But I really want to learn as I plan to keep this bike for quite a while. Here's what I've noticed... :
If I get under 1/3 of a tank of gas (with plenty of fuel in the tank) I tend to have alot of stalling issues while idling. I'll pull up to a light or stop and it'll stutter a few times and die, and when I pull over, I still have plenty of gas in the tank.
Also, The service manual I own for the bike says it is supposed to idle are 1200 RPM, but I cannot get the bike to start consistantly or idle consistantly without stalling. Right now it's sitting around 1450 or 1500.
Thirdly, I was made aware of and oil leak before I bought the bike, and it seems to be getting a bit worse. Right above where the side stand goes down, there is the slightest oil leak...and before I go taking things apart I thought I'd ask for some direction. lol
And lastly, electrical issues...The headlight is rather weak, I don't know if that is electrical or just the light itself. It's only useful while the highbeams are on, and that's only to light up roadsigns. The high beam indicator doesn't come on while the high beams are on. And my Speedometer backlight won't come on, while my tach's will. Makes night riding very difficult lol
Thank you guys alot for anything you can come up with.
Hi and welcome to the forum!! The best recommendation I can give you right off the bat is to devote some time to going back through past threads here and reading up on your bike. Most, if not all, of the questions you have asked have been addressed fully and you will find the info very helpful.
Your fuel starvation issue could be the result of a clogged gas filter located on the top of the fuel tap (valve) inside the gas tank. Is the inside of your tank very rusty? Could also be a bad fuel tap that needs a rebuild kit. If you leave the gas cap open slightly does the bike still stall? If so, your gas cap vent may be clogged. Take the cap apart and examine/clean. A new cap gasket can be purchased from mikesxs.com. Since the bike is almost 30 years old, you need to check out the intake system to be certain you have no leaks. Check out the info on intake manifolds between the engine and carbs. Also, check out the info here on replacing the VERY SMALL "o-rings" (and maybe idle screws, too) under the idle mixture screw on top of each carb. This website, mikesxs.com, has stuff that will fit your '81 XS400. Other things to consider updating, if not already done so by P.O. are the fuel hose, vacuum hose, spark plugs and ignition wires. The original headlights are sealed beam (can't replace bulb) and are dim because they were lower wattage than we find on modern headlights. The charging system is marginal on our bikes. You can order a replacement headlight reflector unit from candlepower.com that will take a modern H4 55/60 watt bulb. Order the unit that comes w/o bulb then purchase a SilverStar Ultra bulb for an excellent headlight. Also found in a thread here is info on replacing your stock tail/stop bulbs (2) with ultra bright LED bulbs. This lessens the drain on your charging system, compensating for the increased wattage of your new 55/60W headlight bulb.
This should get you started.
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My son's troop was pretty active. Went to a camp owned by the district council but leased to the state's National Guard. Some new Guard recruits were there training that weekend. Our young teens guys shamed them on the trials. Some of the recruits were too scared to repel down a cliff while our boys were zipping down like it was nothing. What a hoot!! They had an extensive high rope course at the same camp.
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I find some knock off air filters for $14 HERE. I was thinking about picking up a pair.
I put in new spark plugs and the new fuel filter today, and the bike ran beautifully for a few hours
I also noticed I have a 2 into 1 exhaust, and after reading the forums here I don't think thats standard. Am I correct in that assumption? Mine is a 1980 XS400 (special I think?). Would the bike run well with new exhaust without rejetting the carbs? Again, the idle screws still have caps on them, so nobody has touched those. I won't know for sure about the jets until I take the carbs off in December. I guess its more for my curiosity and to make future plans if I ever decide to change the air filters.Thanks for the suggestion OllieB, I'm trying not to add any aftermarket stuff if I can help it, at least not while I'm on a poor college kid budget.
Yep, you're correct about the exhaust. That may be a plus, though. If the bike runs well after the usual tweaks (idle mix screw adjustment, new plugs & wires), nothing to worry about. The next step is most definitely the new o-rings for the idle mix screws. Sounds like no reason to open up the carbs. Carb removal isn't really that difficult and it will be much easier to drill out the plugs with the carbs removed. They are connected by a metal bar. Leave them that way. After doing the o-rings, put it back together and see how it runs and idles. Tweak the idle mix screw adjustments, if necessary. Set the idle speed. Your next step will be to check valve adjustment unless you know this was already done by the P.O. Last, but not least in the tune up is to balance the carbs. I haven't done that yet to mine but will be doing so soon. You can make your own manometer as described here or elsewhere (http://www.obairlann.net/reaper/motorcycle/manometer.html) or buy a balancing kit (http://shop.ebay.com/items/carburetor%20synchronizer?_dmd=1&_sop=12&rvr_id=135762117158&MT_ID=69&crlp=5619449165_1&tt_encode=raw&geo_id=1&keyword=carburetor+synchronizer&adgroup_id=1617145025). You want one with 2 gauges.
If you will be riding at night and your headlight is still the O.E. type that is a sealed beam unit, buy a new reflector (http://store.candlepower.com/ca631quheleu.html) without bulb and buy a Sylvania SilverStar H4 bulb. Replace the standard filament type stop/tail bulbs )2) with these: http://stores.ebay.com/warden-jp2008/_i.html?_nkw=1157&submit=Search&_sid=1006980729 Select the ones that are described as : 2 pcs "1157 13W High Power LED (Red) Stop/Tail Bulbs". The LED bulbs will reduce the amp draw on your bike's charging system and compensate fot the added draw by going up to the brighter headlight bulb.
I get the "poor student" problem. Been there years ago myself. I have given you lots of things to think about but all will improve your bike in the most important ways - reliability, proper performance and safety. Keep us informed and PM me if you have any other special questions. I don't have experience with engine tear-down like some here but have picked up some knowledge along the way about the more general stuff.. Don't forget to check your chain adjustment!
BTW, haven't seen that site for Yammy parts before. Thanks for the link. If the filters fit, they should be fine. That's a good source for all of us. Let us know what you think of them.
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i need to do the same to mine as its stiff and you dont get that "click" that you used to when you turn the indicators off. but il probably dismantle it to give it a good clean!
I have successfully used a teflon lube spray to loosen things up. Works great and will last a good long while.
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I found pictures of what the air filters are supposed to look like, and I think the ones I have are almost unusable. The metal on the sides of the air filter are not attached so the whole things falls apart if you touch it. I think this is why its hard for me to attach them to the hoses. I saw some pics where others have used a different air filter in lieu of the stock filters and boxes, but it sounds like the carbs have to be rejetted for this to work. This may be too much work for me at the moment, so I might try and find some original replacement air filters.
One problem at a time though. Once I get the air filters properly connected, I'll get back to you if it is still having problems idling. The previous owner said he cleaned the carbs out well, so I'm going to avoid doing it myself for a few months if possible. I should have more time for such a task in December. Thanks all!
New replacement O.E.M. filters are available but they are about $70 a pair, IIRC. My preference in these older bikes is to leave them the way they left the factory and not mess around with filter, exhaust and carb jet changes. You get yourself into a good bit of work and expense. I think your plan to find replacement O.E. filters is a good one. If you find a set of decent used ones and the rest of the filter is OK, you can always wrap it with new mesh as some have done and described here on the forum. Get your filters and go from there. Good luck.
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So I need a new set of taillights, and considering integrating the taillight to the seat assembly. I'm a fan of LEDs, but how will the electrical system play with such type of lighting? For reference, I ride a XS400D
And also an aftermarket tach, since the one I have is probably not so accurate (very sticky)
LED lights will be great for your bike since they draw a fraction of the amps that filament bulbs draw. The electrical system is marginal on our older bikes and anything we do to reduce the draw helps. If you install LED turn signal lamps in the rear you should replace the front turn signal bulbs with LED bulbs. You will also have to replace the flasher unit with a new one compatible with LED bulbs. The only issue I have with aftermarket replacement units is that some are small and not very bright, reducing the visibility of signals which tell others what you are planning/doing.
While at it, replace the sealed beam headlight (if not already done) with a reflector unit that will accept the brighter 55/60 watt H4 headlight bulb for safer night time riding.
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It seems the air filters have a mesh cage connected to a metal cylinder. The metal cylinder part sticks out of a hole in the filter box, and this is the part that connects to the hose leading into the carbs. The rubber between the carbs and the engine and between the carbs and the air filters looks brand new, so I assume they were recently replaced. The air filters look home made, but with the original cage. The metal cylinder on the cage was wrapped with black electrical tape, so there was no way in hell they were going to fit inside the rubber. I removed the tape, but I still have a hard time pushing the metal into the rubber. It seems to be an extremely tight fit, and the metal part of the air filter retreats into the filter box when pushed making it even harder to connect. I think the rubber intakes may be a size too small? Did the intakes and air filters I described sound normal, or has something been 'ghetto rigged'?
I unscrewed the battery box between the two air filter boxes to make this task easier, but that was rather annoying. I got the left air box connected solidly, and the right one still lets air in at the connection so I will work on it tomorrow. It ran great today after I fixed this. It idled around 1600 which is high (should be 1200 I read). I ran it around the block for about 30 minutes and I had no loss of power all the way up to 8000RPM. The idle didn't stick when I made it to a stop sign, so its some improvement I think.
There 'was' an inline fuel filter, but I managed to break it yesterday :-/ I will get another one, it looks the K&N one I saw on a previous thread. I am trying to avoid removing the carbs because I live in an apartment and management gives me dirty looks when I work on the bike, but if I have to I have to.
The idle screws still have the metal plug from the factory, so I will have to drill those out to access the screws. If the bike is running, what are the downsides of having it idle a little high?
Thanks for your suggestions, I am not only new to the XS400, but this is my first motorcycle.
The connection problem between the air filter and the filter intake sounds weird. They should be just a little tight but not impossible to get on to the metal ring. Sounds like you may have some damage to that side filter box.
An idle in the range you describe is not going to hurt anything. While the specs call for 1200 rpm, that will not always be consistent. We are spoiled by fuel injection and computers on our modern cars and think older carbureted motor vehicles should perform the same way. Even on a bike of our vintage in perfect condition, we may see some slight variation in the warm idle speed from one run to the next or even with climate changes. Idle speed rpms are also somewhat a matter of preference. Some folks like to have the idle so low that they hear the individual cylinders fire one at a time. Others prefer idle speed closer to 1500 rpms. You shouldn't need to turn the idle screw under the carbs all the way out to achieve a near spec idle speed though. Sounds like you are getting closer.
Be careful when you drill out the plugs. Use a bit just slightly smaller than the opening and go slowly with light pressure. Be certain the bit is centered so you don't drill into the metal of the carb. Once you have drilled out the plugs and removed debris, note where the screws are set then slowly turn them in (clock-wise) to see how many turns out they were set to. Do this gently and don't screw them down hard when you feel them seat. As I said, probably about 1.5 turns. You can also remove the screws to inspect the VERY SMALL o-rings at the bottom of the screws. Even ones seem to look ok need to be replaced as they become distorted and hardened. Inspect the tips of the idle mix screws. Sometimes the very pointed tips break off and remain in the hole, causing problems. Most likely this will not be the case with yours as no one has been able to monkey with them. Even if you re-use the original screws, install the new o-rings and set to 3 full turns out to start. Some have found 2.5 works on their bikes while others need up to 4 turns out. If you play with the settings, only move them 1/8 to 1/4 at a time to see how idle & performance is affected. A lean mix caused by leaking o-rings, intake manifolds and/or air filters can mess with the idle speed as well as low rpm performance. BTW, is the vacuum hose from one of the intake manifolds to the top of the vacuum tap (fuel selector under left side of tank) in good shape? If not, replace it as well as the gas hose.
A gas filter is not original equipment on our bikes and not necessary if the inside of your tank is clean and the filter on top of the vacuum tap is ok. The connection problem between the air filter and the filter intake sounds weird.
An idle in the range you describe is not going to hurt anything. While the specs call for 1200 rpm, that will not always be consistent. We are spoiled by fuel injection and computers on our modern cars and think older carbureted motor vehicles should perform the same way. Even on a bike of our vintage in perfect condition, we may see some slight variation in the warm idle speed from one run to the next or even with climate changes in ok.
If you don't know when or if your spark plugs, plug caps and ignition wires have been replaced, do so. The plug caps should be 5 ohm type. Take one to your Yammy dealer and get new ones. Replacement wires can be bought cheap from MikesXS. Spark plugs: NGK BP7ES are about the best and pretty cheap at Advance Auto. If your plugs have an "R" in the number, they are "Resistor" type plugs and not proper for our engines. On a used vehicle of unknown service recirds, I prefer to start with new stuff so I have a base line.
Engine oil: If you live in Hotlanta, GA an excellent oil would be Valvoline Blue Diesel grade oil 15W40. Why Diesel oil? It is better suited to our older engines and has MUCH MORE anti-wear additives than modern gas engine oils. This oil is ok with cycle wet clutches, too. No need for Synthetic oil. NAPA stores sell this oil if you can't find it at other places. They also sell NAPA brand oil filters made by "WIX", one of the older filter companies and they make excellent oil filters.
I think you have selected an excellent bike for your first machine. Personally, I prefer smaller engines bikes as opposed to the massive two-wheeled recliner/cruisers we see here in the U.S. Be careful!! Car/truck drivers are not looking for motor cycles and will look right through you, not even seeing you.
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Since you are new to this bike, the first thing you should do, if you haven't already done so, is to take some time to search back through old posts about carb issues on this bike. I did so when I bought mine in June this year and the info I learned was tremendously helpful.
First, before a carb tear down, I would go through all the connections to make certain they are proper and not leaking air/vacuum. You described an issue with the intakes. These systems are set up from the factory to run properly and any deviation can cause problems. Yes, leaking air at the intake side of the carbs can cause problems. If you can't fix the filter boxes, get used replacement ones. Open the boxes to see if the air filter elements are intact. You can find info here about how to resurface the old filters. Next, look at the rubber (and metal) intake manifolds between the carbs and the engine. If they have never been replaced, do so with new manifolds and gaskets. These are notorious for leaking as they age and develop cracks. Also, on top of each carb is the idle mixture screw. If your carbs have never been disturbed, these screws will be covered with a metal plug from the factory to prevent us peons from messing with the adjustments. Usually these screws are set to about 1.5 turns out as per EPA emissions requirements. If the plugs are still there, remove them by carefully drilling them out. Under the idle mix screw is a very tiny o-ring that deteriorates and can cause issues such as you describe. I bought a new set of screws and o-rings. Start with the screws about 3 turns out (counter-clockwise). Run the bike then set idle speed again. See how it behaves. If you just turn the original screws out to 3 turns and don't replace the o-rings, you will still have issues.
Let us know how it goes. You can buy the manifolds and jets/o-rings from mikesxs.com. Those from the XS650 also fit our XS400 bikes.
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clockwise raise revs, anti lowers
Drewpy, maybe he is confused and is really talking about the carb balance screw!
junununu, If you mean the phillips head screw between the carbs, leave that alone for now as it is used to balance the carbs. The screw for adjusting idle speed can be reached by hand under the carbs from the right side of the bike. This "screw" has a knob on the end of it that can be turned by hand - at least it does on my '80 XS400. Make adjustments to the idle speed after the bike is thoroughly warmed and you have ridden it for a few miles.
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recycling an old topic. I'm basically having the same issues as the OP. I enrichened the mixture and used the balance screw enough to get it to hold at 1200-1300 idle. I also screwed the throttle stop screw all the way out and just in enough to where it doesn't die(I hope I did this right), but I'm still having the high idle issues. I'm still running a tank of seafoam as we speak, but its not done yet, I'm afraid to go anywhere because my kickstart also is shot, but thats another post. The electric start also doesn't start with a bit of throttle to it, if that helps in the diagnosis.
why does the idle come down when the front brake is pulled all the way in? when parked at my house, the idle also comes down a bit when i turn my lights on(sometimes).
Have you replaced the small O-rings that are found at the base of the idle mix screws? These get hard and deformed and will leak air causing just what you describe. Same symptoms with my bike. After I installed a set of new idle mix screws and O-rings, engine behaved as it should with idle mix screws set at about 3 turns out.
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I suppose anything can be debated, but physics are physics. If you have 2 bulbs that put out the same amount of light, one in white and one in red, then you put them behind a red lens- the red one will transmit more light through. The only way the white one can be brighter is that if actually puts out more light than the red one to begin with. The red lens does not convert light to red, it filters out all wavelengths other than red. If there is more red to begin with, more will make it out the lens.
You know, I had forgotten about the physics. Been a long time since my physics class. Makes perfect physics sense to use the red LED with a red lens. I stand corrected!! Will edit my original post so others not reading all the posts will not be misled. Thanks.
They were becoming my friends I was there so much lol j/k. They do have my new air filters though. That is the main reason for going today.
XS400 Brake Caliper
in Classics
Posted
Good question! I was wondering about the XS650 ones also. NOS prices for a replacement are usually pretty high.