XS400L 1983: Should I repair or part?

I have an XS400L 1983 that I've been riding to work all the time. Nice bike. Started to have several problems (other threads) so took it to a young mechanic who seems to work well on bikes.

Now I wonder if it's worth spending more money on this bike since I can't do much myself on the bike apart from small maintenance jobs. I need to think this out... should I have it repaired and keep it, or maybe sell it in good condition? Or should I part it over Ebay? Or sell it as it is to someone with mechanic's skills and tools?

The compression is not equal on both cylinders, a difference of 30. An "air test" shows that air is leaking out the intake valve. The valve clearance is ok. So it's a valve that's gone or going. Big job - would need to open the engine.

Needs a carburator kit too most probably.

The spark is weak - which explains my startup problems and later runs ok. So there is an unknown electrical problem. It's plaguing me for months now.

I'm not a collector of antique bikes so I wouldn't want to put in a large amount of money on the bike just for the sake of restoring an old bike. I don't know if I can still ride the bike with a valve dying on me?

Should I sell it as is to someone who can do the work himself (herself) on the bike or sell it in parts? Or is it worth it to have some of the repairs made (change the valve) and do the rest myself over the winter and keep it for a while more?

What do you say?

 

This is a debate I've had with myself for some time now. I've got an eye on a Ninja 500, but the $1,600 price tag for a USED one means I can spend quite a bit on repairing my XS400 and still come out ahead (especially since the used Ninja might need work too!).

Of course, I do all my own work. You say you can't work on it yourself, well, buy the factory repair manual as well as the Haynes and memorize them both. Get some tools from your local auto parts store and have at it! Lots of people dumber than you fix cars and bikes all the time. If you pay someone to do the work, then it's a lot less likely to be worth it. If you just aren't willing/able then it may be best to sell it as a "project bike" and get a better one for yourself.

But, opening the engine is not that big a job -- I've done it on cars before, and I've had zero formal training: I just read the book, and had someone help me the first time. Probably the trickiest part is going to be getting the engine out of the frame without dropping it. Removing the valve may require a special tool (I haven't done this type before) but rather than buy special tools, they can often be fabricated on the cheap or borrowed from a mechanic friend. Or, take the head into a shop and have them replace the valve, they should charge you a LOT less because they didn't have to take the engine out and apart and then put it all back together. I've done things like that and half of the time, they do it for free because it takes more time to do the paperwork than it does to do the work.

You can live with that weak spark. I think all XS400s have weak spark -- I'm almost convinced they came that way from the factory. As long as you've got a good battery and a good alternator to keep it charged, she'll start up electrically (still, I use the kick start on cold mornings to avoid tempting fate but on warm afternoons the starter works great). Your electrical system is probably fine.

Full carburetor kits are seldom needed. Pretty much everything is re-usable unless you can see obvious signs of throttle shaft seal or bowl gasket leakage, or they pour gas out the intake. My bowl gaskets are rock hard and must be 20+ years old but they don't leak, so I haven't replaced them. Usually when people "need a carb kit" all they really need is a "good carb cleaning". One thing that you may want to pay for is setting the idle mixture after reassembly, as it's NOT an easy job. But you can make a homemade sync tool to sync them yourself pretty easily and cheaply.

In short, paying someone doesn't pay, but doing it yourself usually does.

 

I did buy the OEM manual (close enough to my bike: XS400J), Haynes and some more.

Taking the engine out and having it opened by the mechanic to change the valve, that is an interesting option that hadn't occured to me. I know a mechanic who would do that for me if I bring him all the gaskets and other parts that would be needed. I coud even watch and help... and learn. What I fear is opening something and seeing 3 springs fly out and re-reading the manual to find out that I needed to slip some tool in there to stop those springs from jumping out.

My carbs don't leak. Nothing leaks in fact. But I had a hard time with the mixture. Glad to hear it's not just me being to dumb. Some use a "color tune kit". Spoke to some auto part sales clerk about that - never heard of it. Don't know it I should get one or not. I'll try to have a mechanic set the mixture first and consider the kit if the mechanic doesn't do a good job of it.

The weak spark - ok. But my XS400 starts when cold to stop 30 seconds after. Have to let her be for a minute and repeat the process 3 or 4 times before she will hold. Then she is fine for the day. Makes me go crazy. Once in a while, she starts and holds with no hesitation. :roll:

Maybe I busted a valve trying to start her with pumping the handle the other day. Got a big backfire - but she started finally. Might have burned the valve then. Sure was scary that bang. 8O

I can read books for sure. What's missing is the experience. Knowing a sound is right or if it's telling me there is problem, for instance. But true, I can do a lot of the stuff that's described in there.

Anyway, Tylernt, you're giving me things to think about. Maybe I should get some experience with my XS400. It will pay off later on whatever happens with this bike and I can still part off the bike if I can't handle it.

Tks to the thoughts. Highly appreciated and it helps.

 

Yep adjusting the idle mixture kicked my butt too, it was a really frustrating fight for several weeks. I finally ended up buying a Colortune and only then did it became clear that vacuum leaks in my cracked carb holders were preventing me from getting a good idle mixture. It sure was nice to know I wasn't just dumb. New carb holders FINALLY allowed me to get it right without too much fuss.

The Colortune is pretty obsolete these days with all the computers and gas analyzers. I ended up getting a used one off eBay, about the only place I could find one. They are the stone axe of engine tuning.

Do-it-yourself can be fun and rewarding IF (big if) you have the patience. And try to resist the urge to kick your bike to the curb.

 

Oops I missed this. The XS400 has a self-exciting alternator -- you must rev above 3,000RPM before it starts producing power. If you just start and idle, you are running on pure battery. It may help to blip it up to 4K or so shortly after starting, don't have to hold it there long, just a short visit.

 

1 thing to remember....
From the factory these things are set lean.... tune the carb like you would an XJ 2.5 to 3.5 turns out on the mixture screws....
Just a hair rich makes the 400 J/K/L's runs GREAT!!
curbs that engine braking and and a nice growl to the sound....

Carbs just need a good tuning/cleaning....
Especially the enrichment port... keep that sucker clean...
The J/K/L 's are closer to their XJ cousins in desgn than a normal XS

 

umm, guys;

chacal carries the ColorTune or you can buy it directly from the manufacturer.

The ColorTune is a "shadetree mechanic's" replacement for the EGA. It lets you see the color of the combustion flame, and tune the mixture accordingly. An EGA does the same thing, but measures the exhaust gasses rather than looking at the flame. Problem is, an EGA costs 10X what the ColorTune does even for a CHEAP one.

Ghost; yes they are. They're "half an XJ" and have a LOT in common with the 550s, as well as the rest of the XJ lineage. YICS, baby! Shims-n-buckets, oh yeah! The 10K redline sweetens the deal...

 

ok! I hadn't understood that I didn't have to hold it over 3,500 rpm for the alternator to work. That's nice to know! (I wasn't holding it at high rev but was worried about the battery doing all the work until I actually rode it out.)

I had read somewhere on this forum to turn it 3 turns out from bottom and start tuning from there. I did that and it was effectively very lean at three turns out. White plugs. Did a 1/4 turn in to see the difference - got a deep tan on one plug and white on the other. So I enriched in only the white plug's carb from then on. Maybe and eight of a turn. I thought I was ok with the color on both plugs, although I did only one chop plug run at speed to see the result (the rest before was done from stand still, revving and chopping). Looked deep tan after all that.

Next day, the bike was harder to start and I pulled the throttle a bit 'cause it seemed to help. Got that extra big backfire. Scared the wife (and me too)

That's when I decided a mechanic would have a look at it. :lol:

(If I can't find a colortune around these parts, I'll order one from Chacal for sure.)

And by the way, how important is "a difference of 30" in the compression of both cylinders? It seems it's what I have (my bike, that is). Is it bad enough to stop me riding the bike? Or to cause startup problems, or carb tuning problems?

 

hmmmmm the hard start/backfire make me think a bit out of sync....

 

A 30lb difference in compression indicates a major problem of some sort with the "low" cylinder; you already know you have a valve that for one reason or another isn't closing/sealing properly.

You're not going to be able to "tune around" a LEAKING VALVE.

YES, it's going to cause starting problems and carb tuning problems, especially since it's a twin.

The head is going to have to come off and the valve problem get fixed, period. Otherwise you're wasting your time. You'll only damage the motor worse if you keep riding it.

 

ok - tks for making that clear, BFitz.

I'll find a gasket kit somewhere - probably from Chacal - order a colortune kit at the same time, and maybe a yics tool (the gadget needed to tune the carbs) while I'm ordering stuff to cross the border. Since it'll cost me around 50$ for the broker just to handle any order, might as well get everything at the same time. And the input valve, of course (are both intake and out valves the same?). If you are reading this Chacal, maybe you could quote me a price?

I'll ride my v-star and let the xs400l maxim 1983 rest until this is done, one way or another.

 

Intake valves are usually larger than exhaust, so, probably not.

 

Tks Tylernt.
Next question: should I change all valves or just the burnt one?

 

You may get varying opinions, but I would only replace the bad one. There is no reason to replace them as a set, that I am aware of. Since you'll have the head off, however, it wouldn't be a bad idea to at least check the other valves with prussian blue to make sure they are seating well. If any are out of spec then you can decide to lap, grind, or replace as necessary depending on how far out of spec they are, as well as much you want to spend and how long you plan to keep the bike.

Once you are into the engine, be wary of the tendency to fix things "while you're in there". On one hand, it can be good to do some preventative maintenance things like replacing valve stem seals or etc... but on the other hand, the costs can quickly add up to some serious $$$ of you go overboard.

 

:cry:

I forgot Chacal only has parts for XJs. Mine is an XS.

Will have to try ebay...

 

why not bikebandit.com?

 

right - was getting to them.
They don't seem to have the gaskets but they might have an intake valve that would fit my XS400L
Tks for the hint

 

Yep.. since I decided not to part the bike after all (it starts every time), I'll be searching for a valve come springtime. Right now it's winterized. Riding my V-Star until it snows.

Is BikeBandit reputable? Haven't tried them yet.