Stuck throttle cable 1978 xs400

melted78

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hey guys I'm new to this site I'm picking up a 1978 Yamaha xs400 off my friends dad, last time he rode it was 1998 when he drove into his garage and parked it. I know I need to clean the tank out and bleed out the master cylinder but there's an issue with the throttle it's stuck cannot move it , can it be rusted, could I just open it up and spray some lubricant? 1978 Yamaha xs 400
 
Also would I need metric tools? I have also of course experience in muscle car from the 60s but they are all standard.
 
Make sure the throttle at the carb moves. If it does you might unhook the cable from the carb and then work on it off of the bike .)
 
Welcome.

Just buy a new cable, you need a new one anyways. As for the carbs, Id probably spray any sort of lubricant in there just to wet it up a bit. You still wont be able to touch the butterflies in the carbs because youll have the slide blocking it. You should be able to use a small screwdriver and gently lift the slide to get some lube in there. The slides arent connected to anything except fragile rubber diaphragms that you wont have access to until you remove the tops of the carbs. More than likely its a seized throttle cable..

If you plan on riding the bike down the street, you have a small list of things to check off.

You need to completely rebuild the brake system, including new brake lines. You will need a new battery. Youll need new tires. Youll need to change the oil and probably replace a couple seals along the way. You need to go over all the maintenance with the engine.

At the very least, you need to replace the cable and go over all the engine maintenance and get a new battery, and give the carbs a really good cleaning, add an inline fuel filter too. This should be just enough to get it started assuming the bike was running when it was parked. Make sure to take the head caps off and squirt oil all over the lifters and cams and even in the spark plug holes, its probably all bone dry
 
Welcome.

Just buy a new cable, you need a new one anyways. As for the carbs, Id probably spray any sort of lubricant in there just to wet it up a bit. You still wont be able to touch the butterflies in the carbs because youll have the slide blocking it. You should be able to use a small screwdriver and gently lift the slide to get some lube in there. The slides arent connected to anything except fragile rubber diaphragms that you wont have access to until you remove the tops of the carbs. More than likely its a seized throttle cable..

If you plan on riding the bike down the street, you have a small list of things to check off.

You need to completely rebuild the brake system, including new brake lines. You will need a new battery. Youll need new tires. Youll need to change the oil and probably replace a couple seals along the way. You need to go over all the maintenance with the engine.

At the very least, you need to replace the cable and go over all the engine maintenance and get a new battery, and give the carbs a really good cleaning, add an inline fuel filter too. This should be just enough to get it started assuming the bike was running when it was parked. Make sure to take the head caps off and squirt oil all over the lifters and cams and even in the spark plug holes, its probably all bone dry
Thanks for the reply,i took off the tanks and loosened the cable i tried to move the carbs throttle plates manually with a screw driver and they are stuck is there something im messing here? i though with the cable loose i could move the throttle by hands of with a screw driver
 
Update, it was the carbuerators butterflys that were stuck sprayed some pb blaster broke it loose. when i fliped the carbs upside down and moved it i did not hear the floats moving, im pretty sure there seized my question is what kind of carbs do i have and whats the part number for the rebuild kit. thanks fo the replies
 
Start a "build" thread and keep all questions to this one thread. It will help people keep up with what your doing and what you have. There will be a lot less confusion. Post pics of the bike and what you are having issues with. That will also help us a lot.
 
Yes you will need metric tools. You would also have better luck with the screws with s JIS set of screwdrivers. Get a couple 10mm and 12mm wrenches for those "two wrench" bolts. I find those the popular sizes on the along with an 8mm and occasional 7mm. Off the top of my head I don't remember axle nut size.
 
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