cegan09

I have not, should though. However before the one clear line i have would be about half full all the time. Now it is completely full all the time. I'll check the petcocks once i run through most of this tank of gas.

I have been all over the diaphragms, they are excellent. The idle is weird, it isn't constant, sometimes it wants to die, others it idles at 2k. I think this is because they need to be synced, and the idle screw fine tuned however.

Turns out you were the winner. I had the floats wrong. I thought they were set right, guess i was wrong. I had them too high, set them too low, and they started overflowing, set them again, and its running now. It needs some fine tuning, idle isn't perfect, seems to fluctuate when it wants to idle. It also pops a lot when you let off from mid to high RPM. so it needs some tuning, but the fact is its running, and that is more than i could say yesterday.

I had thought that, since i did replace them recently, however i set them to stock via the workshop manual. I will probably pull them and check them against the old floats to see if there is a difference in heights.

Alright, i'm hoping this is my last thread of this type for a long time. The bike is so close to running properly, but its not. If i let it sit for a while, or cover the carb openings and push the starter a few times to draw fuel through it will start. It will run beautifully for about 5 seconds, reving freely as you adjust the throttle, then it just dies, nothing you can do. Repeat the waiting game or covering teh carbs, and it will repeat this . I know this points towards a fuel starvation issue, but i can't for the life of me figure out what is wrong. carbs have been cleaned quite a few times. All jets are set to stock. Needles have not been touched by me ever. Floats are set to stock height per the workshop manual (25mm +/- 2.5mm). Idle mix screw set to stock (1.25 turns out). There is fuel going to the carbs, one of my lines is clear, and it is never more than half empty. I do not have in line filters, honestly know where they are if i have them. I'm assuming there are filters in the tank at the petcocks, but honestly i don't know. if someone can give me an idea of what to check or change i'd be very grateful. I'm about as sure its a fuel problem as i can be. I have checked spark, have spark. Timing was set in the spring, hasn't been touched. New battery, new coils, new spark wires, new plugs, new spark caps, new floats.

thanks guys. I'm headed to the local shop after work since i need plugs, i'll ssee if they have caps too.

so no one knows?

so I recently got parts in to fix my carb problems, only to learn i now have spark issues. One coil is dead and the other going. I want to replace the whole spark system, however can't find what kind of caps to get. I threw a multimeter on the existing caps and got a 9.x kohm reading, so i think they are 10k resistive caps, can anyone confirm this? Would there be any benifit to going with a different cap? Bike is a 76 XS500. thanks

I was wondering what can be done to stiffen up the front end of my bike. The front will compress under just the weight of the bike. I have a spare set of forks, new seals to put in, and a set of S&W aftermarket springs. Is there anything else I can do? I just don't like how much the front compresses before you even set off to ride. thanks

how do they work when the bike is running? both my xs500 and by friend's kz400 exibit the same thing you describe with the engine off, but work fine with the engine on.

I think i found the problem. One of the floats has liquid in it. Time for a new one.

Thanks, i will pull them off and look into what you suggested. The timing was off, however has been fixed. I know the engine is good, thought it does need an oil change, just since its been a little while since the last one. When it isn't exhibiting this "puking" problem it pulls very well. I'm pretty sure that this issue is linked to the starting problem, since it kicks right up until this starts. I was on it today, and it started to bog, and was leaking fuel from the carbs when i stopped. Assuming that they are linked i'll test the carbs and see if i can't figure it out. Thanks again.

I've had this issue on and off for a few weeks. When i go to start the bike, turn the petcocks on, ignition on, kick it over, the bike resists starting, but also the right carb starts to drain fuel. Its a decent stream of fuel, not sure where exactly it is coming out, as I've seen it from both the engine and air filter side. I've taken the carbs apart a few times to try and find a problem, and nothing looks wrong. Any ideas what might be wrong? When it doesn't start doing this the bike is pretty good about starting in 1 or 2 kicks. thanks

Thanks. I'm not sure how, but i think we have it dialed in. It started on the electric start for the first time in over 6 months today. One question, one of the carbs has been "puking" now and then. Happens usually right after running, when its sitting on the kickstand. Right Carb just drains fuel out the air intake side. I've taken the carb apart to check, and i can't find anything wrong. From what i can tell the float bowls are filling. Any ideas?

I suppose i should have made this post first. I'm Chris, a graduating Senior from Worcester Polytechnic Institute. I recently purchased a 1976 Yamaha XS500 from my friend, and we've been working out the little problems its been having. Finally got it running well tonight and got to take a ride. I'm very impressed. This is my first bike, and i'm hooked. The bike needs a few things, most majorly is a tear down and respray of the frame, though its really not that bad. Also needs a new chain and other little parts. Once that is done i'll do little touches to make it my own. some crappy cell phone shots from the shop tonight.

Well, she runs, and well. I think ignition was an issue. At least one wire was bad, temp ones on there, ordering new ones. Still needs some tweaking, like the idle is set for cold, so when it warms up it idles at 3k. I may also need a new coil since one is producing a much stronger spark than the other. some pictures of the bike, i apologize for the poor phone pictures.

I think the main problem was timing. We did some playing and it starts now, still with some difficulty, but it starts. We need to actually set it correctly, probably tonight. Its popping a lot, but i think that is mostly due to carb adjustment. thanks for the other sugestions, i'll be going over everything tonight to check connections and grounds.

Hi, new here, hoping i can get some help. I recently bought a 1976 XS500 off a friend (he bought a '97 yzf600 and needed to sell this one). We're having a lot of trouble getting it to start. I've never been able to get it to start on the electric start, but it did kick over when i got it. Now it won't start with kick or electric start. It will roll start, and when its running it runs like a champ, and pulls well. I did disassemble and completely clean the carbs since they needed it badly, and have since put the correct jets back in it (main and pilot jets were changed over the winter during a rebuild, and correct sizes couldn't be found at the time). I've had them back apart many times to check and recheck, and i can't find anything wrong with them. Once i can get my spark plug socket back I'm pulling the plugs to check them again (looked fine a week ago), as well as get an adapter so i can run a compression check. Any suggestions on things to check? Thanks