The XL600 thread

Discussion in 'Thumpers' started by Gregster, Jul 6, 2007.

  1. davek181

    davek181 Long timer

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    "stock" is dependant on years it seems. I did a quick run through the years using an online lookup for parts and found quite a variation. I looked up XL and XR and XL Calif for the years and found a lot of differences.


    83 XL 125 112 55
    84 XL 118 110 65 Cali
    84 XL 120 112 65
    85 XL 115 112 65 Cali
    85 XR 122 45
    85 XL 118 115 62
    86XL 115 112 62
    86XR 128 110 45
    87XL 118 115 62
    87XL 118 112 62 cali

    My current configuration is 125 115 42 XR carbs with XR needles and enlarged needle jets. My favorite yet. Knowing me I will play around with it some more come summer. I am kinda thinking 130 108 might be fun to try.
  2. lookfar

    lookfar from the land of OZ

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    Yup, thinking that the cam chain is a bit stretched and just about due for replacement.
  3. bdcorrigan

    bdcorrigan Been here awhile

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    Yep cam chain change it before it goes. My 86 did the same thing.
  4. crobox

    crobox Been here awhile

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    Thanks Dave. Well I guess I will pull off the bowls at some point and have a look to see what I've got in there. According to your findings, I should have 115 112 62 in there ('86 XL), unless some previous owner changed something. I should have written it all down!

    A friend came over today and noticed some black soot around the exit of the Supertrapp, on the fender and the heat shield on my pannier. He told me that was a sign of being too rich. Any thoughts about that?

    Jetting is a mystery to me.. but one that I'm sure I will know a lot more about in a few months.

    Does it still make sense that my super-short power drop-outs seem like an indication of lean-ness?

    Thanks,
    Christian
  5. Carter Pewterschmidt

    Carter Pewterschmidt Long timer

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    The soot could mean it's only rich in the idle circuit. With stock jetting and a supertrapp I'd say your bike is in a lean state if anything. A stage two jet kit is about what you need. That is going to give you a 125 or a 128 main and putting your previous 118 main into your secondary carb. You will need an adjustable needle for your main carb. You can buy an XR one or you can get some litttle washers and shim your stock needle.
  6. davek181

    davek181 Long timer

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    I had intermittent power drops that I attributed to be carb dirt issues that eventually proved to be a stator dying. I have heard of CDI boxes failing intermittently also. Usually jetting is more repeatable and dependent upon throttle position. You can get a feel for leanness by turning the fuel off while riding. It will die of course but it goes lean first, so if it feels like that it is too lean.

    As mentioned, with a super trapp, and stock jetting I think you are lean anyway. Black soot splattered around is normal for the Super Trapp in my experience. It diffuses the exhaust in all directions unlike others where it directs it straight out away from the bike. Slow jet, or pilot jet mixture is adjustable by the mixture screw. Adjust for best idle warm and if the screw ends up about 1 1/2 to 2 turns out it is as good as it gets. I have found on my bike that a leaner pilot jet aids warm restarts. If I let the bike sit and get cool, I usually have to use the choke to restart it. Even in the summer after a day of work choke is needed, it will fire first kick if I do use the choke. After that though, it starts in one kick or even half a kick flawlessly.

    Check your jets. I would start at 122 or 125 primary, and 115 or 118 secondary. Main jets are set for full throttle running, and needles and stuff dials in the rest. You need to get the mains right before anything else can be set effectively. Take the main jet sizes and add together and divide by 2 to get an overall average. I have found my bike runs best in a range of 118 to 122, dependent upon altitude . So if you take the suggested range of 125, 115, or 122, 118, you get a middle of the road 120 average, which is a good start. Then once the mains are close you can play with needles and needle jets and slide synchronization if you haven't been tortured enough.
  7. crobox

    crobox Been here awhile

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    Thanks Dave and Carter-

    You two guys rock.

    I just pulled the float bowls to have a look, and I am at
    118 main
    115 secondary
    62 idle

    So I'm thinking, based on your suggestions, that I will source a 122 or 125 for the main (or maybe just get both? That would give me more options for playing around). Then put the 118 in the secondary.

    A few questions...
    -Dave, when you say "Main jets are set for full throttle running, and needles and stuff dials in the rest." What do you mean by playing with the needles to dial it in? Do you mean shimming the needles up with washers? To get at the needles you have to go in from the top of the carbs, right? does one have to remove the carbs from the bike to do it?

    Are the jets JUST the little threaded item at the bottom, with the flat-head slot and the little hole in the middle? Or when you say "jets" does that also include the item with the female threads and the hex "nut" outside, that the flat-head item screws into?

    And lastly... if one is going UP in jet sizes, would it be possible to just drill out the hole in the bottom to a bigger size? Are there charts somewhere that show what size the hole is for a given jet? Or is that a closely guarded industry secret? I know we're talking about very small holes here, but with a little lathe and the right drill bit it seems possible to me. Has anyone ever tried?

    Thanks,
    Christian
  8. davek181

    davek181 Long timer

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    OK, I will try to explain what I know in a semi understandable fashion. In the simplest form there are two circuits in the carburator(s)

    1. Idle circuit. For idle only, though it can affect part throttle to a small degree.

    2. Main circuit. All fuel above idle goes through the main circuit, or main jet circuit. In between idle and wide open throttle you have the throttle slide which gives you speed control. Attached to the throttle slide is the needle. It is a tapered rod that restricts fuel flow from the main circuit by throttle position. When the throttle is nearly closed the needle is nearly all the way down into the needle jet and since it is tapered the fuel flow is limited by whatever can fuel can squeeze around the needle jet and the needle. Even though the fuel is coming from the main jet it is restricted for less than wide open throttle operation. so in essence the fuel rate, or jetting is controlled by the diameter of the needle within the needle jet. since the needle is tapered it allows more fuel with more throttle opening. Consider it an adjustable main jet for simplicity of thought. Once the needle is completely removed from the needle jet by throttle opening, or full throttle, only then do the main jets deliver full flow. That is why you have to get the mains set right first since the other adjustments are really restrictions of full flow.

    Luckily most of the experimentation has already been done by the factory, so minor main jet and/or needle depth adjustments are usually all that is needed. You adjust needle depth in the needle jet by moving it up, for richness, or down for leanness. Often they have a c clip that you can move to a different position to fine tune mixture. In lieu of a clip, often deleted for emissions reasons you may have to add small washers underneath the needle to move it up higher, or richer.

    Yes the main jets are just screwed in the bottom of the emulsion tube which screws into the carb. The actual needle jet sits above that and usually stays in the carburetor.

    The jets are just a fixed orifice that can be drilled as necessary if you desire. Jets are cheap enough that I don't bother myself with drilling them out. I did however drill my needle jets due to lack of alternate sizes. There are charts that give sizes if you are interested in "rolling your own" so to speak.

    I can change needle position and even slides themselves with the carbs mounted. I have done it many times. Pull off the carb top caps and with a long good fitting #2 phillips screwdriver remove the two screws that hold the slide to the linkage. the needles are below that bracket and just slide out with the help of a magnet. It takes a little practice and patience but is quite doable. I really hate to pull those carbs and once you get the technique mastered a needle change takes only a few minutes. You may opt to not even mess with it anyway after getting the mains close.

    I commute on my bike in the warmer weather 40 miles a day and I have found that subtle changes like one notch of main jet or a needle movement is not necessarily noticable at first. I like to ride it for a week or so to decide if I improved things or not.

    I hope I answered some of your questions or cleared things up a little. If not please feel free to ask more. Maybe someone more eloquent than me can put it into more understandable terms if need be.
  9. crobox

    crobox Been here awhile

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    I get it. Thanks Dave.
  10. joexr

    joexr Banned

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    Yes tou can drill jets. Sizing is millimeters. 100 is 1 MM. , 120 is 1.2 MM. and so on. If you end up too big you can soft solder them shut and redrill. Your best bet is to convert MM. to inches and use indexed drill bits. Google drilling jets and go to XS11.com. They have a sizing chart.
  11. R. Smith

    R. Smith n00b

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    Found the parts on ebay, thank you for the heads up about the cam chain.
  12. Carter Pewterschmidt

    Carter Pewterschmidt Long timer

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    For sure you'll need the jets switched out but as stated here if you're having a stumble at a very small throttle opening like 10 or 15% then the idle or pilot jet could be lean. If so step up to a 65 pilot jet.
  13. MAXNX

    MAXNX Adventurer

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    Jul 5, 2009
    Oddometer:
    59
    Location:
    North Lake,WI
    Got most of my suspension parts today
    XR400 triples were a perfect fit. I think the hardest part is going to be making the bracketry for the stock headlight, luckily I have an aftermarket speedo, so that will be a little easier, ignition switch will kinda suck to mount too.

    Anybody have pics of what they did?

    I ordered a stainless brake line for xr400 and it has a banjo on the master side,doh wish I would have looked at that closer.

    Excited to see how she handles with a set up suspension.
  14. Carter Pewterschmidt

    Carter Pewterschmidt Long timer

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    Use a XR650L upper clamp. It has the ignition mount and fits the 43mm forks. No headlight mount though.
  15. davek181

    davek181 Long timer

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    I made a mount for the ignition switch and stock gauges out of a flat piece of steel that had holes punched for the ignition switch and gauge mounts that bolted to the bottom of the upper triple. I even bent it just right and was able to get the steering lock to function too. It was a lot of work though, I would opt for the 650L top triple if I did it again and fab up a mount for the gauges. There is a gauge mount on them already but different from XL. I even bought one on eBay to use if I ever get bored.

    I have kind of the same problem again since I am mocking up a USD fork swap from a CR made up of parts I have gathered from eBay. I have the forks, triples, front wheel with speedo drive all ready to go, just have to deal with the switch and gauges now.

    I have a pic of the XRL upper [​IMG]but I am unsure how to upload it for you.

    [​IMG]
  16. dirtywhoer

    dirtywhoer jay

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    brockton, pa. the best riding ive seen.
    I have been lurking around for a bit now and thought this felt like home. I picked up old xl600r that was less then pretty but ran great. Shortly after i traded and then kicked my self for it. I just got it back. It was used abused and put up wet like a dirty whore.
    After tearing it down i cried. The whole top end was fried. The biggest problem is the head and rocker cover it is beyond cooked. I was thinking of placeing a small lower rod bearing from like a briggs and stration motor in the center jornal of the cam. If not ill have to empty my life savings into a new used top end in order to reabilatate the xl. Plese help ...........
  17. mcma111

    mcma111 Long timer

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    Dirty,

    If you need a cam I have one for sale.
  18. mcma111

    mcma111 Long timer

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    Anyone want a set of XR carbs? The ones with the float bowls that has the removable plug. The mount that holds them one to the other is broken though. Free, you pay shipping.

    I also have a shock with the remote resivour. Has LE Engineering sticker on it so it may have had some work done to it.
  19. davek181

    davek181 Long timer

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    I'll take the carbs if you are serious and still have them.

    Might be interested in the shock too, how much?
  20. mcma111

    mcma111 Long timer

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    Dave,

    PM sent