Hard start

[cegan09]

Alright, after a month of the bike being in the shop, and general craziness in my life, I have the bike back. It is running decently, however it still is very reluctant to start. I have found the most reliable way to start it is to cover the carb openings with your hand while hitting the electric starter so that they flood slightly. Once you do this it will reluctantly start, then need to be warmed up with the choke like normal.

The shop cleaned, set, synced, balanced the carbs, so those should be ok. Ignition timing was set as well as it can be, and valves were set and adjusted. My only thought as to what could be causing this is the stock airbox has long since been replaced by cone filters, and as of lately, due to how I have to start it, no filters. I’m thinking this means there isn’t as much resistance pulling in air, so that engine can’t pull the fuel it needs to start. Is this plausible, or am I showing my ignorance to carbs.

It runs beautifully once started and warmed up, but even when warm, if you turn it off and try and start it, it isn’t happy about it.

Thoughts?

[duaneage]

Alright, after a month of the bike being in the shop, and general craziness in my life, I have the bike back. It is running decently, however it still is very reluctant to start. I have found the most reliable way to start it is to cover the carb openings with your hand while hitting the electric starter so that they flood slightly. Once you do this it will reluctantly start, then need to be warmed up with the choke like normal.

The shop cleaned, set, synced, balanced the carbs, so those should be ok. Ignition timing was set as well as it can be, and valves were set and adjusted. My only thought as to what could be causing this is the stock airbox has long since been replaced by cone filters, and as of lately, due to how I have to start it, no filters. I’m thinking this means there isn’t as much resistance pulling in air, so that engine can’t pull the fuel it needs to start. Is this plausible, or am I showing my ignorance to carbs.

It runs beautifully once started and warmed up, but even when warm, if you turn it off and try and start it, it isn’t happy about it.

Thoughts?

I would check the intake boots between the carbs and head, make sure the clamps are tight all the way. What you describe could also be bad intake boots or leaky gaskets in that area, spray wd 40 on the boots as the engine runs and if the speed increases you have a leak.

[happysnapper]

These bike never liked being played about with, so could be the air filters as you said.

Other thing to try would be to go up a number on the plugs to a hotter one, as this sometimes cures your problem.

The best way I find to start my xs500b is full choke no throttle and hit the start button and she fires up no probs.

Hope this is of help!

[cegan09]

intake boots are good, but i will check again as described. I'll try the plugs if for nothing else as something to try. I'm really wondering if my air filter theory is correct, since it might explain the inablility to idle below 2k. If there isn't enough restriction to induce some "pull" on the fuel system to get it going, might that not cause it to behave as it is? I have an old airbox off a Kawasaki KZ400 that i can try and rig up, but the air box to this bike is long gone. If this theory seems to have some merit i'll try and find some more restrictive filters for the bike.

if i'm talking nonsense though please correct me.

[drewpy]

you could try and cover the inside of the cones up. it is something to do with the diaphram air intake and the vortices of the air induction.

try and see if you can use longer intake hoses between the cones and carbs as this is what I did on thew 400 flat-tracker!

drewps

[cegan09]

That's an interesting idea. I will add it to my list of things to try. Just did 135 miles, and she ran like a champ once going. pulled well, it was fun.

[JimR]

intake boots are good, but i will check again as described. I'll try the plugs if for nothing else as something to try. I'm really wondering if my air filter theory is correct, since it might explain the inablility to idle below 2k. If there isn't enough restriction to induce some "pull" on the fuel system to get it going, might that not cause it to behave as it is? I have an old airbox off a Kawasaki KZ400 that i can try and rig up, but the air box to this bike is long gone. If this theory seems to have some merit i'll try and find some more restrictive filters for the bike.

if i'm talking nonsense though please correct me.

Hi,

I had some 500's that would not idle below 2k and felt quite week in performance until high rpm was obtained and bad starting it turned out to be (in the case of the 2 part head model to be the secondary head gasket and in the case of the one piece head it turned out to be an intake valve with a 'cut' in its seat best way to check is to do a wet & dry compression check just to discount or include these causes of your problems.

Regards Jim

[cegan09]

do you know what compression should be? I can't find a number to compare to. I did a test and got about 125psi from each, actually a little higher, maybe 128. That seemed to be about right based on my calculations for engine spec/size. That was dry, i'll have to redo it and do a wet as well.

[JimR]

do you know what compression should be? I can't find a number to compare to. I did a test and got about 125psi from each, actually a little higher, maybe 128. That seemed to be about right based on my calculations for engine spec/size. That was dry, i'll have to redo it and do a wet as well.

Hi,

I would guess that to be a bit low but I guess with age the bike will not get a much higher reading without everything returned to factory (costly ) but I do think you may have some motor problems there

Regards Jim

[cegan09]

hmm, not really what i wanted to hear, but ok. I was planning on stripping the bike completely down this winter, so i guess what's adding the engine to the mix. Luckily i have a second engine, don't know if it has all the bits, but at least 95% of them.

I'll re-run the compression test, both wet and dry, see what i get for numbers. I'm also going to try a few things in regard to filters to see if my theory on idle/starting has any merit. My list of things that need fixing keeps growing, but i guess what can i do, these things come with a bike that is 33 years old. Thankfully i enjoy working on the bike as much as i do riding it.

[JimR]

hmm, not really what i wanted to hear, but ok. I was planning on stripping the bike completely down this winter, so i guess what's adding the engine to the mix. Luckily i have a second engine, don't know if it has all the bits, but at least 95% of them.

I'll re-run the compression test, both wet and dry, see what i get for numbers. I'm also going to try a few things in regard to filters to see if my theory on idle/starting has any merit. My list of things that need fixing keeps growing, but i guess what can i do, these things come with a bike that is 33 years old. Thankfully i enjoy working on the bike as much as i do riding it.

Hi,

what do expect with an engine that was before it's time ?? if the 500 had been produced later it would have been sweet (newer tech) rather than the over size lump that played up at the drop of a hat

Regards Jim

[cegan09]

Dragging this thread up briefly. I did a compression check the other night after changing oil, and looking at the cams. I'm getting 130psi on a dry test for both cylinders. I need to figure out a way to get a few drops of oil in there without spilling oil everywhere before I can do a wet test. I think my problem may not have been as bad as I was as I originally thought. Yesterday while taking the bike out for a mile to warm the oil for changing, it died at a stop as it does when not fully warm if I’m not paying attention. I hit the starter and nothing, just a clicking from around the battery. (I assumed relay, but based on some other reading I guess solenoid?) I gave it a kick and it fired almost before I had the full kick stroke in. I assumed low battery was just not powering the starter, But a check of the battery showed ~12.7V, and after a charge to be sure, the starter was doing the same thing. So I’m assuming either the starter is toast, or my grounds are fouled up. I'll check both with my tear down this winter. So I’m wondering if my hard start problem was as bad as I thought. I've been lazy and ignoring the kick start, but I’m thinking that I shouldn't have been. The electric start has been slow as long as I’ve had the bike, and I just assumed that was normal. More things for me to check. I'm starting the tear down this upcoming week. lets hope I don’t' find any major problems.

[XS 500]

Dragging this thread up briefly. I did a compression check the other night after changing oil, and looking at the cams. I'm getting 130psi on a dry test for both cylinders. I need to figure out a way to get a few drops of oil in there without spilling oil everywhere before I can do a wet test. I think my problem may not have been as bad as I was as I originally thought. Yesterday while taking the bike out for a mile to warm the oil for changing, it died at a stop as it does when not fully warm if I’m not paying attention. I hit the starter and nothing, just a clicking from around the battery. (I assumed relay, but based on some other reading I guess solenoid?) I gave it a kick and it fired almost before I had the full kick stroke in. I assumed low battery was just not powering the starter, But a check of the battery showed ~12.7V, and after a charge to be sure, the starter was doing the same thing. So I’m assuming either the starter is toast, or my grounds are fouled up. I'll check both with my tear down this winter. So I’m wondering if my hard start problem was as bad as I thought. I've been lazy and ignoring the kick start, but I’m thinking that I shouldn't have been. The electric start has been slow as long as I’ve had the bike, and I just assumed that was normal. More things for me to check. I'm starting the tear down this upcoming week. lets hope I don’t' find any major problems.

I never got my XS500 do start with the electric starter. After I learned the technique to kick start her she always starts on the second kick. First one with full choke and she coughs, next kick with half choke and she starts immediately. To bad for my g/f though, she weighs to little for the kick so I bought her a XJ500 instead... now I dont have to share the xs500 with her

[cegan09]

It is funny how some bikes favor one method over the other. Mine does hate the electric start, and used to love the kick start, but i'm lazy. My friends kawi KZ400 will never start on the kick unless it is fully warmed up, but pops into life instantly with the electric.

after the rebuild i'm expecting it to start on a kick or two every time. I do need to find a choke lever though. Mine is gone, so i have to hold the piece up with my hand to use the choke. I think i saw one on ebay today.

By any chance do you have the compression numbers for your bike? I've been trying to find someone to compare mine to since i can't find what they should be normally.

[Cy Welch]

intake boots are good, but i will check again as described. I'll try the plugs if for nothing else as something to try. I'm really wondering if my air filter theory is correct, since it might explain the inablility to idle below 2k. If there isn't enough restriction to induce some "pull" on the fuel system to get it going, might that not cause it to behave as it is? I have an old airbox off a Kawasaki KZ400 that i can try and rig up, but the air box to this bike is long gone. If this theory seems to have some merit i'll try and find some more restrictive filters for the bike.

if i'm talking nonsense though please correct me.

Those air boxes (and related parts) are pretty easy to find on ebay. Otherwise, your carbs NEED to be rejetted, as the cone filters WILL affect the running. Unless the idle mix has been adjust properly also (which I guessing it has not) then it won't idle well (or start for that matter). Also, these are pretty much the same carbs as the XS1100's use, and the mantra on the XS11 site is clean the carbs really good, then clean them again, and then clean them again, meaning it generally takes at least 3 times to get them clean the working well. I know I cleaned mine about 6 times before I got them right. I also had to replace the o-ring under the idle mixture screw spring as those flatten out and go away mostly over the years and these things will NOT idle well without that o-ring. That o-ring is available if you look around, but can be a little hard to find. Also, try spraying wd40 at the ends of the throttle rod and if the idle speed changes that means the butterfly seals are shot, you can get those from MikesXS.

It is a LOT of work to get these carbs right, but when they are, it should start easily, I almost never need more than 1/2 choke on mine, and then only for a short time.

[cegan09]

Thanks, i'll be sure to replace those parts. I had plans to replace all seals and gaskets on the engine and carbs this winter. I'm also looking at getting an ultrasonic cleaner, so i can make sure they are all clean.

Personally i'd like to not go back to the airbox, and stick with the cones. So i guess i'll be learning the proper jetting for that setup, or finding a way to make the cones more restrictive.