Thanks man. I should mention I didn't go into the bottom end so the pulse generator never got touched. It has run. Before I rebuilt it I got it going by push start and rode it around for an hour; it ran fine. I thought the ridiculously hard start was caused by low compression (after putting in the new stator) so I rebuilt it. Before the rebuild I got 60PSI cold, now I have 90PSI cold. It has run since the rebuilt, but it certainly has not run long or started easily at all. I'll pull the carbs for the 5th time. Earlier this week I put in the fresh 65 pilot, everything was clean and jets were clear. I couldn't see it being a clogged pilot but it's possible. It's also possible that the choke is plugged. It's as if it's just not catching. When it does start, it fires right up and away it goes, but it just doesn't catch 98% of the time. I was thinking I wasn't kicking it fast enough and that I might be too small to start this machine but I think I'm kicking it pretty good. I get lots of sparks when I do the spark test. TDC, pull decompressor, hair past TDC, heavy, solid, swift follow through. It's gotta be fuel related. I should be seeing a soaked plug with lots of choke kicks right?
i used to do that but i find that if i grip the front brake lever and have my thumb under the throttle it holds it against the idle stop. then when she fires your hand is right there and ready to rev it a bit to warm up. the brake also keeps the bike steady and it doesnt roll around whilst putting you back into it. im only 65kgs (140lbs), i should know.
The CDI decides when to fire the plug based on the pulse from the pulse generator, it can and does fail causing the spark to fire at the wrong time. I spent weeks messing with my carbs looking for problems when my bike was hard to start and had a loss of power and extra hot exhaust, it turned out to be a bad CDI. After replacing the CDI I got 1 kick starts and full power at top-end. If the CDI is firing way too early or way too late you'll never get ignition, mine was slightly too late causing the mix to still be burning when the exhaust valves opened. You'd never have known the timing was off without a timing light or similar diagnostic tool, the spark was plenty strong, I had spark, fuel and air just not at the right time.
I have different starting/running problem. My 1983 XL600 starts OK. If I set idle up so it does not stall when coming off choke, it then idles too high when it is real warm. Before it gets real warm, it will occasionally "cough" then stall. I sprayed carb cleaner up through the idle jet of left carb (from float area of carb) so I think it is clean. The "cap" on the air adjust screw came off so it is set about 2 1/2 turns out. I've adjusted it to maximize the rpm when engine is warm. The resistance of the stator checks out to be about 340 ohms, just a little on the high side, and I can feel voltage going to the plug when I ground it and kick it over. Spark is not real bright though when I am just kicking it over. What can I do to make it so idle does not keep getting higher and higher as engine warms up? What makes it "Cough" and die? When engine is hot, it has good response and power from idle through high speed. Maybe I just need an extension on the idle adjustment screw so I can adjust it easily without getting off the bike and taking out a screw driver. Does anyone make such an extension?
Interesting. I'm going to pull the carbs tonight just to make sure but I don't think that's where it is; I've made sure they're clean and blown. I do have spark, but like you it's just not "catching". It also runs hot when it does run. It will start if everything is PERFECT and the spark just happens to catch the charge. It might also explain why it doesn't idle well, as if the timing is late. If it isn't carbs I'm going to have to place my bet on the CDI. The pulse generator has the right resistance and does produce a small voltage when I kick it. Secondary coil has the right resistance, and I put a ricky stator in it. Only thing left is the CDI.
I had the same stalling problem that turned out to be a tight valve. If you check and recheck the valves, maybe even readjust just to triple check. My XL600 only coughs and dies sometimes when I leave the choke on too long. Sucks in traffic. Or, if I just turn the choke off. I must rev the engine or be applying throttle under load when turning the choke off or it kills the engine. Can't just turn choke off at idle. My idle setting may be the cause for this. I have it set low enough that it never idles too high when at full operating temperature. There may be your compromise: have idle high enough that you don't have to rev engine while turning it off, or vice versa. Then again perhaps you can't get it to idle that low. Perhaps your weak spark is actually an issue, causing it to not be able to reliably idle that low. Triple check your valves though, when I had a tight valve, it would idle fine for no more than a couple minutes before sputtering out. Follow up with me here.
Had a similar issue with mine. Was going to be lazy and put some seafoam in the tank when linkage between the carbs fell off and had to remove them anyways. Bike ran pretty good but would stutter occasionally with high idle when warm and ran too hot. Pulled the bowls off to find green nastiness inside primary. Jets partially clogged and float catching on the choke tube. Pulled all jets soaked and brushed clean, massaged choke tube with dremel for float clearance, drilled idle jet out to 62 and put a 120 jet in secondary carb. She runs sweet and the plug looked great when I pulled it.
I recently had very similar behavior with my restoration. Carbs were really clean, valve clearances were OK, spark...seemed good for a stock stator. My bike would start pretty well but would die when I tried to switch off the fuel enrichener (aka "choke" tho it aint a true choke). My problem? the fuel air needle adjuster. Just needed to back it out 2,3/4 turns (approx). These bikes I hear are pretty sensitive to that adjustment, so you might try fiddling with that when you get 'er running at first. I think the stock screws have a metal tab which prevents turning for SMOG reasons, but a lot of people have ground that off with a file (as had mine when I got it used). Try that anyway...
Oh yeah, I forgot my more recent stalling issue when I let it get really low on gas. Apparently my fuel filter's element was floating loosely at the same time. It straightened right out when I got a new filter and a tank of gas. I finally found a high-quality filter that is compact and has a 90 degree bend in it. That along with some great motocross style colored fuel line and it was perfect. Haven't had a sputter out of it yet since then. That is if you don't count the time I left the choke on too long a couple times. Geed, goodies in the mail for you as of yesterday, delivery confirmation and priority mail. Enjoy. I've got a funny story for you once you get the packages.
Someday I will have to check out the motocross fuel line. I think that and my dad's 3way brass fuel line junction connector soldering-fu will finally keep my fuel line from making any contact with the "hot parts". Looking forward to the package(s). I just got email confirmation on that from USPS. you didn't have to do PRIORITY
Guess what? I saw your message before you edited it. I cleaned the carbs out again, didn't find anything clogged though. I turned the pilot screw to 1,3/4 turns out. I jumped on it, choke on, no throttle, didn't give me anything. Cleared out the cylinder, no choke, no throttle, and it fired up in 4 kicks. I let it run for a couple minutes, I then adjusted to pilot screw to the spot where the revs peaked. Turned it off, ate supper, went out again, fired up in 3 kicks. At this point I'm really friggin happy. I go for a ride, on this ride I turned it off 2 times. The warmer it got, the more kicks it took to start it. The last time I got it started it felt like it "just caught" on the bottom of the 6th or 7th kick. I rode around some more, nice clean idle, went home and turned it off. Went to start it again, no dice. My dad was there and he said he saw puffs of white smoke coming out the exhaust when I kicked it over. It gave a loud "pop" out the exhaust at one point too, I tried a little choke, did nothing, cleared the cylinders, no choke, turned the idle up by 1/2 turn because I know how hot engines like a little throttle but I didn't want to give it any twist (I fear the kickback) and it still did nothing. The white smoke and backfire and the fact that the hotter it got, the more kicks it took makes me think it's running lean on the pilot. Tomorrow when it's cold I'll check and see how many turns it's at. I set it at the peak idle speed when hot. I'll then put it back to 1,3/4 and see if it'll go again.
Good to fear the kickback. A week later and my ankle is still black and blue but at least I can start the bike for my 5 day vacation tomorrow. My kickback was my own fault by ignoring the decomp lever when starting with the switch off.Loaded cylinder with fuel and BAM= sprained ankle. Never again.
Uniter, The screw you are turning is either an air screw or a fuel screw. The Pilot is a jet inside the float bowl. If the screw is towards the front of the carbs, it is for fuel adjustment during idle. If it is towards the rear (closer to the airfilter), then it adjusts the air during idle. If the carbs still have the stock jets (both Pilot jet and the Main jets) then yes, they probably are lean. Go up a size or two, and the bike will be happier.
It's called the "pilot air screw" in the shop manual, at the front of the primary carb. Closer in means less air, more rich. As you turn it out it allows more air, more lean. {edit: I'm actually not sure about that ^; I keep getting conflicting answers about which direction is richer/leaner} It's got a 65 pilot. I ordered the pilot for an '85 (which happens to be a 65). I previously ordered N424-21 series jets in 65, 68, and 70, but contrary to the fact that I though they would fit from their description and dimensions online, they did not fit. That's when I just got the honda jet from '85. I don't know where I would be able to get a 68 pilot for this machine. I have 135 main primary, 132.5 secondary, and clips in richest groove. Uni filter, Xr's only pipe, backfire screen still in airbox, spark arrestor still at the end of the pipe. I have an '87 BTW, 62 pilot stock. Live near sea level. Tomorrow I'll just set it to 1,3/4 see if it'll go again, and not touch the screw. I'll ride it around until hot and see how it starts. It sure does run hot though. White smoke, backfire, hard to start when hot all indicate lean right?
glad you seem to be making some progress, ya, i edited the response because I went and checked what I had written down and that said 2,1/2 or something like that but i'm running a pod filter and a different airbox so my numbers may not apply. but I'm betting that adjustment gets you closer to a normally running bike. might not be bad idea to just check to see what the plug is looking like for any obvious lean/rich issues, but I'm guessing that your pilot jet is awfully close. The needle positions are curious to me since I don't think my 1984 CA model has them, but I'd want to return them to the stock condition first since the fuel/air screw seems to be having an effect. Only tweak one thing at a time with these carbs, it's very tedious but hopefully you get a better idea of what leads to what... good luck! adam
Now on my '83 both jets are stock with the Pilot being a 55 and the Main at 125. I was told that the '83's were the best jetted out of the box 600's. True or should I change. Not that I am having any issues just want to run a little cooler. But wait, looking outside it is 43F right now so there goes the warmth:eek1 :eek1
Uniter, <o></o> <o>On my 1985 XL600R, I run the following:</o> <o>Primary Main :122</o> <o>Pilot Jet : 68</o> <o>Secondary Main: 118 ( I will probably bump this up to a 122 also)</o> <o>Mixture screw: 3 1/4 turns out</o> <o>I have never even looked at my needles to see if they have clips....</o> <o>My bike has 15,000 miles and is stock other than a Ricky Stator, Uni-Filter, and the airbox snorkel is removed. Starts first kick almost every tiime.</o> <o></o> <o>Hopefully this will get you started in the right direction.</o> <o></o>
^ Thanks :) I have a pipe on it and I do plan to uncork, and I live at sea level so my jetting is likely going to need to be richer. About the pilot; Where did you find a 68? And what series of keihin jet is it? I just ended up ordering the 1985 jet from honda (which is a 65) no year came with a 68. I tried the N424-21 jet series but it didn't fit.
