Prince George Vintage Motorcycle Club
Technical Section => Engine => Topic started by: Hans on April 30, 2020, 09:24:06 PM
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My lovely XL600R, still giving me grief. Hard starting and stalling. I've had the carbs out twice this spring, getting pretty good at it. I've replaced the pilot screw, the tip on the old one was bent and the oring shot. After that it started on the third kick, but the setting was way out of wack with the screw 2 turns out. Finally got the idle to settle and the screw seemingly to the right spot which was another couple of turns out. Was idling for a bit, then it just died. Started right up again, held the idle for another couple minutes then died. I chucked the plate on it and ran it around the neighbourhood a couple times. Felt kind of slushy like it was overfuelled. Got it home, turned it off. Put the screw in a turn (leaner) and couldn't get it to start. Turned the screw out a turn it started but would die after about 5 seconds and then be hard to start. I have a new theory, I need to go to a larger pilot jet so I can turn the pilot screw in more. The pilot screw is so far out that a quarter turn goes from too lean to too rich. The screw has a couple shoulders on it, the specs say any where from 1.5 to 3 turns out, it's at least 5 turns out to start. Anyone want to chime in on this theory. Of course that last time the carbs were out, I didn't check the size of the pilot jet, I think I can get to it with the carbs still in the bike.
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If you want to do a 'deep clean' take the the carb completely apart and I'll put it in my ultrasonic cleaner for an hour. I have a little 2.5 liter cleaner that does 1 carb at a time.
Might help.
Olaf
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So, here is the latest. Took the bike for a good ride. For the first 10 minutes, runs great, idles perfectly. After that, it starts to occasionally pop while idling, then eventually just shut off. I'm now 3/4 way convinced that it is electrical. My researches have suggested that maybe I have a failing stator, it's apparently a common problem with XL600Rs. The resistance measures low compared to the specs. The ignition coil measures perfectly within spec. So the dilemma is whether I throw my hat at a new stator. They ain't cheap.
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So, here is the latest. Took the bike for a good ride. For the first 10 minutes, runs great, idles perfectly. After that, it starts to occasionally pop while idling, then eventually just shut off. I'm now 3/4 way convinced that it is electrical. My researches have suggested that maybe I have a failing stator, it's apparently a common problem with XL600Rs. The resistance measures low compared to the specs. The ignition coil measures perfectly within spec. So the dilemma is whether I throw my hat at a new stator. They ain't cheap.
I hope this isn't a dumb question/comment because I did not go online to look up information on your bike first. Many trail bikes rely on the stator to directly charge the coils. Older street legal trail bikes then had additional windings on the stator to charge a battery for the lights. If that's what you have it may be your stator and you have to take the plunge. If not, and your battery is staying charged, it would make no sense to think its your stator.
Peace & Grease, Dennis
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Yeah, this silly thing has 3 circuits. The ignition circuit, a DC circuit for the battery, and an AC circuit for the headlight. Headlight only on when the engine runs. Battery for the dash, signal, and tail lights.
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Didn't Rusty Bucket have a situation where a coil (coils) measured perfect on the bench but failed when they warmed up (or something like that)?
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I seem to recall something about that. On my old GSX400, I replaced the coils with ones from a slightly more modern GSXR750. The originals would crap out when they got hot. Then I replaced the regulator/rectifier unit with one from a Yamaha.
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Stator on order, figured I better tackle the oil leaks while I was at it. 2 leaky spots, the cam chain tensioner and the kickstart decomp lever.
(https://i.imgur.com/3q6NKl2.jpg)
(https://i.imgur.com/OvvdAtB.jpg)
(https://i.imgur.com/libnk6f.jpg)
You'll have to turn your head, imgur insisted on rotating my photo.
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I hope you get the Red Menace running reliably enough for some dual sport riding. With many destinations not being visitor friendly yet, I'm hoping to do a forestry service road, forestry rec site camp/trip some time soon. It would be great to get a few dual sport riders out for such a trip.
Peace & Grease, Dennis
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I've been collecting bits and bobs and getting them installed as they arrive. First was a seal for the decomp. The manual said "remove sping and pull out shaft" Google said " remove the retaining pin first". I had to get Jeff to do so, it was in there pretty good. Next was an oring for the cam chain tensioner. That ended up being a fairly easy job once the cam cover was off. Stator arrived on Saturday, so I got the side case off and cleaned up and now have the new one installed. That should be it for the engine other than a good bath.
Next will be cleaing up the exhaust and beating the joint back into shape. It was really stuck at the midpipe when I was removing it, misusing a screwdriver as a chisel/prybar was in order. Had to buy the new seal there as well.
It coming along. I hope it starts when I'm all said and done....
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The header cleaned up pretty good, now to get some exhaust paint.
(https://i.imgur.com/2DJ0PIu.jpg)
Not too sure what to do about this end though....
(https://i.imgur.com/plEYnaC.jpg)
Can tell this thing has been "Farmer'd" a bit. There was a sheetmetal screw holding the exhaust shield on.
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Neil did some welding up of the exhaust and I painted it up. Got everything put back together over the last couple evenings. After getting the cam cover back on, I found that all the valves were tight, so got them adjusted to spec.
https://youtu.be/23IT9I_a7rM
Started first kick. And second kick, and third kick..... I'm probably jinxing myself.
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Excellent.
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Now she's marking her territory......
Leaking out from where the stator wiring comes through the case, should have used some sealant there I guess. Mumble grumble.
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Now she's marking her territory......
Leaking out from where the stator wiring comes through the case, should have used some sealant there I guess. Mumble grumble.
Isn't the stator in a dry/non oil area?
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Nope, wet, very wet.
Found a new source of weeping oil in the valve cover area, the rocker arm shafts have a copper washer, seems to be a bit of leak there. Unfortunately to fix that, the engine has to come out again which I don't feel like doing right away for some reason.
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my oil leak solution to owning British and American bikes........
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Well, since mine is Japanese, a little RTV and tightening up the gasket properly (oops, cockeyed it) works wonders. Other than the slight top end leak which requires pulling the engine.
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Situation update. "Fixed" the top end leak by backing off the rocker shafts and re tightening. Looks to have reseated the copper washers. Took a look at the spark plug after yesterday's ride and it was a slightly alarming whitish colour, so out came the carbs in in went some slightly richer main jets. I didn't touch the idle circuit in the hope it wouldn't affect the good starting I've been experiencing. Took that opportunity to polish up the float valve seat and replace the float bowl gasket, hopefully that helps the fuel weeping.
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She just continues to break my heart. Got the new larger tank, so could go further afield. Fought with fuel leaks for most of March, finally got on top of those. Up and quit on me on the last Tuesday night ride. Popped, wouldn't pull, run ok, pop, die. Strt after a minute, pop , die, end of story, home on the trailer. At home, zero spark. Checked the stator I installed last spring with the multimeter and Zero ohms through the ignitor coil. Must be shorted. Pull it further apart this weekend if I can find the time.
Old bikes.... always have a spare.
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Definitely fire the mechanic..... wasn't paying attention to the Ohm settings on my multimeter. Stator now tests good. Ran the wiring loom looking for shorts or open circuits and everything checked out all the way to the coils. Coil reads good on the Ohm meter. Signal generator reads a little low. No spark to be seen. Plug was a but sooty, but nothing too bad. On a "throw the cheap stuff at it first" attempt, I got a new plug and trimmed back the plug cable an 1/8th of an inch. Nice healthy spark. Put the Ohmmeter on the old plug, reads an open circuit. Scrape the soot, reads OK. Maybe the plug just fouled?
Anyway, I've transferred the insurance to the SRX400, it started 2nd kick after the winters sleep.
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So, being the masochist that I am, I'm back at it. Since the last post 4 years ago, I've intermittently tried a few things. A new kill switch, a new crank sensor, a new coil, and a cleanup of the worst of the wiring gave no joy. The carbs have been in and out multiple times, and I'm not sure where some of the bodywork is. That as it may, I've tried 2 new thing. One is a new genuine Chinese CDI. The other is to reset the valves. I was wondering if maybe they had run tight and were lifting up when it got warm. So, I had one intake valve super loose, one good. One exhaust valve was good, and the other was tight. Checked the spark by spinning the engine over with a drill and it was really healthy. Put some fresher fuel in the tank and got it to fire up on the 10th or so kick. Think the carburetion is way off as it started without the choke. Ran it up and down the street, shut it down, and firing it up on the first kick. Figured that was enough pushing of my luck for the evening and packed everything up.
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Despite the amount of grief and anger they generate its hard to toss them to the curb isn't it? A little like a relationship (I've only heard about).
I wonder if there is a compounding of issues here that is causing said mechanic to pull out precious hair? Is it possible there is a warping in the head or the mating to the cylinder that would cause the valve clearances to go so far out? This, coupled with an iffy spark might be enough to cause the running issues? Once everything is nailed down is it possible to do a compression test cold then hot?
Just my 2 cents.