XS400 ideas anyone?

[SteelGunna]

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.

[OllieB]

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.

[HoughMade]

For the front, you can loosen the fork clamps on the triple trees and slide them up. I wouldn't do more than maybe a little over an inch, though. I am 6'3" and I did 3/4" and there is no negative effects and it seems to turn in a hair quicker. For the back, I think the right way is new, shorter shocks.

This bike is more your size, than mine, though.

[SteelGunna]

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.

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.

[OllieB]

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:

http://www.partsnmore.com/parts/yamaha/xs400/

[BigShrek]

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)

Purchase thick-soled Engineer-type boots...if female, you should be able to get some nice combat/Abby-NCIS/Goth boots that'll solve it

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.

Time for a carb cleaning & replace all fuel lines.

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

Never had that issue.

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.

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

[OllieB]

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.