Kielohawk

I had a simlar issue. My 75 XS500B started dying at stops, and was getting hard to start especially when already warmed up. When I first got the bike, it seemed really cold blooded and took awhile before I could turn the choke off or it would die. The low idle screw acted really funny also. I could adjust it down to about 1100 RPMs and when I would try to raise the idle just a tad by turning the idle screw, the RPMs would race to about 2500 and stay there. When I would slowly rotate the idle screw back a tad, the idle would drop to 1200 RPMs pretty fast. I could not adjust in between. WHen I turned the choke on for a cold start, the bike would start but would only idle around 1300 RPMs then slowly fall for about 45 Seconds then it would die unless I gave it gas. I broke open the Clymer manual. Here's what I did to fix my bike... I set the fuel/air mixture screws to factory settings. all the way in till they gently seat, then back out 1 full turn +/- 1/4 That didn't really help. My mixture screws were out about 4 full turns. It had to be running rich. Then I checked for spark. The plugs didn't seem torqued all the way and the spark was good on both plugs. I took the points cover off on the right side of the bike and checked gaps on both points. The gaps were no where near what they needed to be according the Clymer. The gap was about half what it was supposed to be. I adjusted the gaps on both points, then advanced the timing a tad. (turning the whole point base a bit) WOW, what a difference. The bike started right up and ran much better. The choke works normally. Choke on, the RPMs are up around 2000 to 2200 RPMs, after about 30 seconds, choke off and normal idle at around 1200 RPMs. The idle set screw is now fully adjustable from 1000 RPMs and up smoothly. The engine doesn't want to die when you give it a fast throttle advance. It also has a bit more power when running. And best of all, I got another 12 Miles on the tank before I had to kick in reserve. That's another 4 MPG from what I was getting. I also ordered a original owner's manual which has a ton of info in it. I was pretty dissapointed with the Clymer manual. It's kinda like a Haines or Chiltons. It covers a bunch of years and the pictures and directions never seem to exactly match what you got. The owners manual says the tank size is only 3.4 US Gallons. I thought it was 3.96 Gallons. That makes a HUGE difference when you are depending on a certain amount of fuel in reserve!! The manual says that when you have to kick in reserve, you only have 20 to 25 Miles left before the tank is empty. I can verify this!! I had 21 Miles on the reserve when my engine died. I thought I could go 40 Miles with a 1 gallon reserve. Hope this helps. Check your points for condition and gap. It's what fixed my bike. Dan

The Reserve valves should have the small or short (round) pointing towards what you want selected. On my 75 XS500B the right petcock valve long stem is pointing straight back with the short or round forward when it is in reserve. And on my left petcock, it is opposite. When in reserve mode, the longer portion is pointing forward. The first time I ran into Reserve I pointed both petcocks the same direction not thinking that they were the same part #. I had my left carb in OFF mode and the bike wouldn't start. Good thing for KICKSTART after I figured it out! Oh yeah, nice looking bike. Is that the original stock exhaust and handlebars? Do you have any oil leakage on your engine? Hope this helps! Dan

Thanks for replying! I have had the bike for a few weeks now riding it everyday to work. I also have visited just about every website dealing with this model and a few others. I bought a Chlymer manual as well. It answered a few of my questions. 1. Agree, choke is on when lever is down. (Chlymer manual has absolutely nothing in it dealing with Choke- Wierd) 2. Still don't know what this adjustable screw does. It does not seem to do anything. It does make a good anchor for a throttle friction lever (hillbilly Cruise Control) hehe 3. Engine oil checked on maintenance center stand level and not threading the dipstick in to check it. 4. Oil filters are unavailable new, but there are some on Ebay. I am hesitant on buying them because I heard that some are slightly taller and will not fit under the Chain drive gear cover. 5. Fuel capacity is a hair under 4 US Gal. Something like 3.96 Gallons. You have to go to reserve when there is 1 Gallon left. I am presently getting around 42 to 45 MPG. 6. Still not sure why 2 Petcocks. Unless it has something to do with constant fuel flow while leaning the bike either way. (although there would only be 1 carb getting the gas due to no Y tube in place to feed both carbs from either petcock.) 7. I have seen a few seats going on Ebay. There was one that looked like exactly what I needed but it went for about $120. I wasn't online when the auction ended. I really appreciate you replying to these questions. I was starting to lose hope on someone posting! Maybe I can get some pictures and post them here. Is your bike in good condition? I am worried about trying to find either a new exhaust or replacement slip-on mufflers. My header piples are in good shape but I think the right muffler is starting to go. I can hear stuff rattling around inside it. I also have a small oil leak coming from the left front side of the engine around the gasket that is just under the exhaust ports. I have put some 20W50 in it on my last oil change with some oil stop leak. Doesn't seem to work and I don't want to tear the engine down. I am hesitant because of having to deal with the cam chain. Also I have heard that you have to check the Cam Chain tensioner and some kind of balancer often. I think the balancer is on the right side of the engine. Dan

Hey all! I recently received a 1975 XS500B from my Dad. It's in really good shape with new tires, chain, paint job, replaced fuel tank, plugs, oil, seat, grips, and mirrors and it's my first motorcycle. I do have some questions because I have not wanted to fork out $60 for a owner's manual from Ebay. I hope you guys can help me out. The bike runs pretty good and just seems a little cold-blooded. I have treated the fuel with some "Sea foam" because he didn't drive it after he had the engine worked on. Here are my questions: 1. Is the choke off or on when the lever is down? It seems to be Choke "ON" when in the down position. 2. What is the little adjustable screw for on the bottom side of the throttle handle? 3. Do you check the engine oil on the side stand or the maintenance stand? 4. Where is the oil filter located? 5. Does the large adjustable screw on the right carberator effect only idle speed? 6. I think the gas tank is just under 4 Gallons. 3.96? When should reserve be kicked in? 1 Gallon left? 7. I found it odd to see 2 fuel petcocks on the tank. What is the deal with that? I just make sure they are both in the same position. The gas tank isn't a split tank is it? 8. Does anyone know where I can get a seat with stock hinges? THe seat I have on it is kinda rigged to the bike attached to the rear shock mounts. The key lock is not being used at the moment and I would like to be able to raise the seat normally to get access to the battery and such. Thanks! Dan