Cleaned the carbs again and it still doesn't run. I checked my fuel screws and they are both backed out 3.25 turns like my manual said. So what could be the issue? I really wanna get it running. The plugs are a white ish color (lean?). Anyway. Thanks a ton
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Newbie! With some questions of course.
- Thread starter Presdo
- Start date
Pork Chop
XS400 Junkie
G'day Presdo,
I am pretty sure 3.25 is too far out. I recommend you start with 1.5 turns out and adjust 1/4 turn out at a time. 2.5 is probably as far as you will go.
Posted via Mobile
I am pretty sure 3.25 is too far out. I recommend you start with 1.5 turns out and adjust 1/4 turn out at a time. 2.5 is probably as far as you will go.
Posted via Mobile
I put it back in to 1.5 turns and still nothing. I did a compression test on both cylinders and I don't get a reading. 
So I now think that I need to take the piston out and put new rings on it.
Two questions about that - 1. Do I need to take the whole motor out to do this?
2. Will these work? - http://www.disastermotors.com/produ...set-x2-1977-1978-1979-1980-1981-std-size-sohc
Trying to keep my patience here.
So I now think that I need to take the piston out and put new rings on it. Two questions about that - 1. Do I need to take the whole motor out to do this?
2. Will these work? - http://www.disastermotors.com/produ...set-x2-1977-1978-1979-1980-1981-std-size-sohc
Trying to keep my patience here.
Wait a second! You did a compression test and got no reading? Nothing at all? That is just wrong. I don't know what you did, or how, but you should have some reading. You need to redo the compression test, making sure the spark plugs are removed and grounded to the engine and the throttle is wide open. Even a piston with no rings will provide some compression!
If it is still low or nonexistent, get your hands on a leak down tester and determine where the problem is.
If it is still low or nonexistent, get your hands on a leak down tester and determine where the problem is.
If you have no compression at all its valves that are open or not sealing either carbon build up or something else.If you have to take your engine apart to fix this problem you only have to remove the valve covers and the head.
MrStubb
XS400 Addict
Hey Presdo. Don't get too ruffled yet there is usually a simple explanation for these things. I must agree with Scorpio that you may have valves sticking. Sometimes an engine that has sat for long periods will have a valve or 2 stick. This happened on a car I had years ago. I would first put a small amount of Marvel Mystery oil in the intake ports and some in the cyl. let it sit a few days and see what happens. I would use the kick start and not the starter motor so you can feel when it comes up for compression. Even if this does get you back running it won't be long before you'll need to take it apart for a lite rebuild. Use it as a good learning experience as I did with my car.
I haven't done anything irrational yet 
So I made sure that my spark plugs were grounded but that didn't do anything or help with compression.. IF my valves are stuck open, how would I close them..? (could be a stupid question sorry..) That's my only question for now but yea.
Hope you guys are all having killer sunny days!!
So I made sure that my spark plugs were grounded but that didn't do anything or help with compression.. IF my valves are stuck open, how would I close them..? (could be a stupid question sorry..) That's my only question for now but yea. Hope you guys are all having killer sunny days!!
Drewcifer
1976 XS 360 Maniac
Congrats!
late to the party, but the advice you've gotten from all the guys is solid.
If it ran, and now does not, could be a few simple things.
If you bent valves, or they're stuck open, turning the crank manually with a wrench over the bolt under the cover on the left engine side will show you. It will be hard to turn at the bend in a valve, more than just ordinary rotation. Also, with plugs removed, you can look into the bores with a light and see the valve move downwards.
Carbs are a science of patience and cleanliness. They can be boiled, soaked in pinesol, ultrasonically cleaned, cold soaked in parts cleaner with the rubber stuff removed first...etc etc etc. A million ways, but the good old fashioned visual inspection of jets against a bright light once removed, carb cleaner, a guitar string probing, and compressed air to blow out wet shellac that's built up is key. I haven't had inner passage clogging but enough guys have had it to warrant at .10 guitar string gently pushed in and spun around wherever you can get it.
But to be sure it's running, remove carbs and use some starting fluid. If it runs with starting fluid and then doesn't with the carbs in, you'll be confident the carb settings or passages are to suspect. Then you can learn how to assess your carbs, how to clean them, and how to move to the next issue.
Enjoy, the fun is learning and gaining the self respect of being self sufficient. This forum is a family. Here, you will learn the detachment (Sometimes referred to as "the zen") that comes from loving something as fickle as a vintage motorcycle On sunny days out with buddies, the bike will love you, but make a much more alert, sensitive and attentive man! Because you will always be trying to figure out what the broad is saying to you! LOL. And when you ignore her, something goes bonk and she stops loving. X(
Drewcifer
late to the party, but the advice you've gotten from all the guys is solid.
If it ran, and now does not, could be a few simple things.
If you bent valves, or they're stuck open, turning the crank manually with a wrench over the bolt under the cover on the left engine side will show you. It will be hard to turn at the bend in a valve, more than just ordinary rotation. Also, with plugs removed, you can look into the bores with a light and see the valve move downwards.
Carbs are a science of patience and cleanliness. They can be boiled, soaked in pinesol, ultrasonically cleaned, cold soaked in parts cleaner with the rubber stuff removed first...etc etc etc. A million ways, but the good old fashioned visual inspection of jets against a bright light once removed, carb cleaner, a guitar string probing, and compressed air to blow out wet shellac that's built up is key. I haven't had inner passage clogging but enough guys have had it to warrant at .10 guitar string gently pushed in and spun around wherever you can get it.
But to be sure it's running, remove carbs and use some starting fluid. If it runs with starting fluid and then doesn't with the carbs in, you'll be confident the carb settings or passages are to suspect. Then you can learn how to assess your carbs, how to clean them, and how to move to the next issue.
Enjoy, the fun is learning and gaining the self respect of being self sufficient. This forum is a family. Here, you will learn the detachment (Sometimes referred to as "the zen") that comes from loving something as fickle as a vintage motorcycle On sunny days out with buddies, the bike will love you, but make a much more alert, sensitive and attentive man! Because you will always be trying to figure out what the broad is saying to you! LOL. And when you ignore her, something goes bonk and she stops loving. X(
Drewcifer
Quick update/ questions
I took it apart up to the point of taking the exhaust flange things off (where the exhaust meets the cylinder head), and the exhaust is not moving.. ??? My next question is, how do I take just the valve cover and cylinder head off to replace the rings? I can hear a sound when it turns over in the bore that sounds like some piece is broken off in there. So I got piston rings and a new gasket set.
Do I need to take the whole motor out of the frame to do this? (I have a manual, it's just so easy asking you guys.) A step by step guide with helpful hints of common problems of taking it off and putting it on would be awesome. I'm really enjoying learning these things about the bike actually. The weather out here is incredibly nice and its making me anxious to ride it.
A summary
-How do I pull the exhaust pipes off?
-How do i take valve cover and cylinder head off the right way?
-Can I do it with it still in the frame?
-Do our chains have master clips?
Thanks a ton.
I took it apart up to the point of taking the exhaust flange things off (where the exhaust meets the cylinder head), and the exhaust is not moving.. ??? My next question is, how do I take just the valve cover and cylinder head off to replace the rings? I can hear a sound when it turns over in the bore that sounds like some piece is broken off in there. So I got piston rings and a new gasket set.
Do I need to take the whole motor out of the frame to do this? (I have a manual, it's just so easy asking you guys.) A step by step guide with helpful hints of common problems of taking it off and putting it on would be awesome. I'm really enjoying learning these things about the bike actually. The weather out here is incredibly nice and its making me anxious to ride it.
A summary
-How do I pull the exhaust pipes off?
-How do i take valve cover and cylinder head off the right way?
-Can I do it with it still in the frame?
-Do our chains have master clips?
Thanks a ton.
XSLeo
XS400 Junkie
To start, DON'T buy parts untill you find out what parts to buy. You buy stock bore rings then find you need a three over rebore, lost money on the rings.
If you have a repair manual, you have a step by step engine removal and tear down.
#1 To pull exhaust of depends on the year, early two piece exhaust, mufflers clamp on head pipes, later mufflers are welded to headpipes.
#2 read the repair manual.
#3 No, read your repair manual.
#4 Cam chain or drive chain? Cam chain no. Drive chain it can be either way. Aftermarket chain come both ways.
Leo
If you have a repair manual, you have a step by step engine removal and tear down.
#1 To pull exhaust of depends on the year, early two piece exhaust, mufflers clamp on head pipes, later mufflers are welded to headpipes.
#2 read the repair manual.
#3 No, read your repair manual.
#4 Cam chain or drive chain? Cam chain no. Drive chain it can be either way. Aftermarket chain come both ways.
Leo
In response to your answer "no" about pulling the cylinder head off without taking the whole motor out.. The reason that I asked this question is because I read (in another thread) that you could do it, it's just a little bit tight. I was asking how to do it with it still in the frame.
XSLeo
XS400 Junkie
Oops Wrong forum. This is XS400 not XS650. Sorry about that, the XS650 needs the engine pulled. You still need to read your repair manual. It has all the things you asked about.
I guess we could just rewrite the manual on here just for you.
Leo
I guess we could just rewrite the manual on here just for you.
Leo
XSLeo
XS400 Junkie
From the rectifier the red wire goes to battery positive, the black wire to ground.
Leo
Leo
Ok so I replaced the piston rings by following all the steps in the manual. Now, when I try to start the bike, it either doesn't do anything (has the starter sound) or backfires pretty loud. Why does she want to start? Do I need to time my ignition timing? Also, the manual confused me on the part about how to line the ATU back up again, are the two hash marks on the outer part of the ATU supposed to be a 90 degree angle with the bottom line parallel with the surface?
Do I need to time my ignition timing? Also, the manual confused me on the part about how to line the ATU back up again, are the two hash marks on the outer part of the ATU supposed to be a 90 degree angle with the bottom line parallel with the surface?put bike strait
shut tank
drain carbs and shhot compressed air in gas line to unstick
you might have rubber float valve tips, there good and saving seats but stick more
just a thought or pluged piolets
i shut tank and let bike drain carbs on idle sometimes
shut tank
drain carbs and shhot compressed air in gas line to unstick
you might have rubber float valve tips, there good and saving seats but stick more
just a thought or pluged piolets
i shut tank and let bike drain carbs on idle sometimes
Do you have the spark plug wires on the correct plugs? It wouldn't be the first time someone got them on backwards.
And what is an ATU? Arrogant Transvestite Unit?
And what is an ATU? Arrogant Transvestite Unit?
hahahahaha. I actually laughed out loud at thy one Dave But in all seriousness it's the 'automatic timing unit' right? I think that's what the manual said. It's on the left side of the cylinder head under a cover held on by two bolts. I think autozone lent me a bad compression tester because it still doesn't get a reading and this thing seem to be the most simple tool, ever. So it still says 0. Whatever, it blows my finger off the hole. I guess I'll take the carbs apart again is that what I'm hearing? Plugs are in the right hole and have good spark. When I pull the left plug out its pretty wet. Do I need to time the atu or whatever it is, or is it actually automatic?
But in all seriousness it's the 'automatic timing unit' right? I think that's what the manual said. It's on the left side of the cylinder head under a cover held on by two bolts. I think autozone lent me a bad compression tester because it still doesn't get a reading and this thing seem to be the most simple tool, ever. So it still says 0. Whatever, it blows my finger off the hole. I guess I'll take the carbs apart again is that what I'm hearing? Plugs are in the right hole and have good spark. When I pull the left plug out its pretty wet. Do I need to time the atu or whatever it is, or is it actually automatic?
XSLeo
XS400 Junkie
ATU is advance timing unit. The device that advances the timing from the idle timing to full advance timing. Used with the points ignition.
Leo
Leo
