Do you have a way to confirm your tachometer is accurate? Like a timing light that shows rpm? It's just a thought I had after you mentioned it sounds like it's screaming.
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77 xs400 starting problems
- Thread starter thecurryman
- Start date
thecurryman
XS400 Enthusiast
Yeah captchrome I was thinking about shimming it up first to see if that starts to produce some results. Ive got some shims of various thicknesses that I am gonna play around with today. The needle im running is the y264 that I came across on this forum, was told this was a very close approximation to the 5z1. The picture is from xs650.com user 5twins.
I believe it is a little longer than the y265. Middle clip position with 132.5 main and pods on the hpipe has given me the best performance so far.
Tstidham, I thought about this as well. Don't really know how I could test the tach, I've got the idle set at 1200 and the tach holds steady there, when I hit it with the strobe the timing marks line up and it advances like it should. My only thought is that maybe the dash is from a different xs with a different gear ratio on the tach. There are pics of the dash on the first page of this thread if you wanna look. All I can say for sure is that when I ride it on the country roads it loves to cruise at 3k which seems pretty normal to me.
Maybe describing it as screaming at 4k isn't accurate. It sounds like its spooling up when I start to get up there and it feels like it wants to give more. I know these short stroke motors are designed for the high rpms but I'm a novice to bikes and wanted to get some other opinions on it before I blow the motor up. I get it, its hard to really diagnose a problem like that through text but I thought I'd throw it out there anyways.
I believe it is a little longer than the y265. Middle clip position with 132.5 main and pods on the hpipe has given me the best performance so far.
Tstidham, I thought about this as well. Don't really know how I could test the tach, I've got the idle set at 1200 and the tach holds steady there, when I hit it with the strobe the timing marks line up and it advances like it should. My only thought is that maybe the dash is from a different xs with a different gear ratio on the tach. There are pics of the dash on the first page of this thread if you wanna look. All I can say for sure is that when I ride it on the country roads it loves to cruise at 3k which seems pretty normal to me.
Maybe describing it as screaming at 4k isn't accurate. It sounds like its spooling up when I start to get up there and it feels like it wants to give more. I know these short stroke motors are designed for the high rpms but I'm a novice to bikes and wanted to get some other opinions on it before I blow the motor up. I get it, its hard to really diagnose a problem like that through text but I thought I'd throw it out there anyways.
thecurryman
XS400 Enthusiast
When setting clearance for your valves with feeler gauges, how do you determine the correct fit? Should there be absolutely no way to get a .006 feeler gauge in there? Should it be kinda difficult to get it in there? In the machine world .001 is .001 so nothing over the tolerance should fit period. What do yall look for?
I generally aim for the middle and if the spec say .004-.006 I use my .005 blade so it fits with slight drag and the .007 won't go in.
thecurryman
XS400 Enthusiast
Alright cool thats how I've been doing it.
Been working on sealing an exhaust leak. I know there's a crush washer in there but this one has a spacer of some kind on it.left side looks toast. Anybody seen anything like that before?
Been working on sealing an exhaust leak. I know there's a crush washer in there but this one has a spacer of some kind on it.left side looks toast. Anybody seen anything like that before?
Attachments
There are two types of exhaust manifold gaskets I have seen. One is the spiral wound type that you have in your pictures. The other is a copper crush washer type (it looks like a big copper ring). Either works and both get deformed once they are tightened up between the head and the manifold and must be replaced as they are one time use parts.
When installing these gaskets, make sure that they stay in the head securely when you are installing the manifold. If the gasket is loose, use some grease on the face to keep it stuck in position. The grease will burn off and smoke on start up, but at least you will get the proper seal. It looks like your left one moved during install.
When installing these gaskets, make sure that they stay in the head securely when you are installing the manifold. If the gasket is loose, use some grease on the face to keep it stuck in position. The grease will burn off and smoke on start up, but at least you will get the proper seal. It looks like your left one moved during install.
thecurryman
XS400 Enthusiast
Yeah looks like previous owners stacked the two together. One spiraled round with a copper crush washer on top.
thecurryman
XS400 Enthusiast
How sensitive would yall say the mix screws are on these carbs?
thecurryman
XS400 Enthusiast
Looks like this is the last post. Bike was stolen out of my parking lot last night. First night it was there too. Finally got it running great and some fucknut decided to steal it. If you're in the bham alabama area I guess keep a look out for it. Hard to miss an orange motorcycle. Thanks for all the help yall have been. Keep the shiny side up
Seriously bummed out by this, especially after all that work sorting it out. I will be thinking positive thoughts and hope this turns up.
thecurryman
XS400 Enthusiast
Yeah I am right there with you captchrome. It was finally running right so I ordered a chain and a ground anchor, knowing that crime was an issue. I went on a crazy long ride saturday and decided that 1 night in the parking lot would be okay. Had the chain but no ground anchor. It was chained up and stashed in the corner of the parking lot. They came that night and dragged it to the alley where it looks like they tried to lift it up and dropped it smashing the engine case cause there was a ton of oil on the ground and a trail of oil leading to a flatspot where they were able to get it up into their truck or van. The bike wasnt really worth anything to anyone but me, really pulled me out of a bad spot of depression and gave me something to look forward to doing at the end of the day. I doubt I will ever see it again if I am being honest. The officer who took my report only asked me for the serial number, my phone number and to see my license. Didnt even ask for a picture so I suspect in a few months I will get a call from them to come pick up a smoldering pile of rubble with a serial number that matches my machine. Is it weird that I keep having these terrible thoughts that somewhere, some uncultured douche who knows nothing about the beauty of the electro-mechanical machine they have stolen, is violating my sweet baby with their carelessness? It really pisses me off.
Anyways, I am trying to look on the bright side of things. I got a crash course on how to work on carbureted bikes and how to chase down the electrical gremlins. I got introduced to this wild world of vintage motorcycles and all the customization that is possible and more importantly I got bit by the bug HARD. I fell in love with riding all over again. This wont be my last motorcycle by a long shot. I talked to the property owner and they have agreed to install security cameras in the lot. I am ordering another ground anchor as well as 2 D2 chains and some rotor locks and I am looking for a tilt alarm as well as GPS tracking units. This will not happen to me again. My next motorcycle will have F you protection. Doubt I will find another xs400 anytime soon but I have found a honda CB750 from the same era, anybody have some comparisons between the two as far as how easy they are to work on? The xs400 was just so simple it wasnt hard to figure out how it all worked together.
Again thank you for all the help, I will probably lurk the forum and see if I can be useful to someone else like yall were useful to me
Anyways, I am trying to look on the bright side of things. I got a crash course on how to work on carbureted bikes and how to chase down the electrical gremlins. I got introduced to this wild world of vintage motorcycles and all the customization that is possible and more importantly I got bit by the bug HARD. I fell in love with riding all over again. This wont be my last motorcycle by a long shot. I talked to the property owner and they have agreed to install security cameras in the lot. I am ordering another ground anchor as well as 2 D2 chains and some rotor locks and I am looking for a tilt alarm as well as GPS tracking units. This will not happen to me again. My next motorcycle will have F you protection. Doubt I will find another xs400 anytime soon but I have found a honda CB750 from the same era, anybody have some comparisons between the two as far as how easy they are to work on? The xs400 was just so simple it wasnt hard to figure out how it all worked together.
Again thank you for all the help, I will probably lurk the forum and see if I can be useful to someone else like yall were useful to me
