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  1. #1
    butterbean_29512's Avatar
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    XLT1200 nightmare

    Hello all, thought I'd recap the trials and tribulations I have experienced with my XLT rebuild. Bought this thing running in May. Had busted cases, bad crank. Rebuilt, and rejetted carbs, rebuilt motor with SBT cylinder exchange, .5mm over. Ran like crap. Found out PO screwed up carb castings trying to drill out tamper caps. Replaced carbs. At this point I have a complete new engine.
    Engine runs ok. Has plug wires issues. Loads up bad at idle. Carbs set to exact recipe. I go too aggressive on lows trying to clean up. Set at 3/8 on lows. Wife rides it in midrange all day, burns up #1 cylinder.
    Rebuild using new SBT pistons. Send bad cylinder to machine shop to replace and bore sleeve. Fiasco. Idiot tries to charge 550 bucks. Told him shove it. Bought WSM cylinder exchange. So, now I have 1 nikasil standard cylinder, and 2 .5mm oversize steel sleeves. Reassembled, runs good, loads up at idle, not as bad as before. I'm running carb recipe exactly with watersocks off.
    Fast forward to last week....pulled stinger to make slight adjustment to carbs. Set lows to 3/4, highs still at 1.5, watersocks still off. Make several WOT passes. RPM's hunt up and down slightly. Pulled plugs, 1 looks great, 2 and 3 are grey. .Tops of 2 and 3 pistons grey as in lean burning. Took it to lake a couple of days later...had a fantastic #3 cylinder seizure running in midrange.
    I haven't pulled engine yet, but if crank is good I plan to try and rebuild it one more time. This time I have 2 used good OEM cylinders on the way. Going to use WSM pistons and wrist pin bearings. OEM seals and gaskets.
    Question is this....what in the hell am I doing wrong? Passes leak down test both times. Am I screwing up using the mismatch cylinders and pistons. I think I am. Will the .5mm oversize pistons run leaner than a standard size piston at any given carb setting? Certainly looked that way, both oversize pistons ran leaner than the standard one at any given carb setting. Any thoughts? When reassembled this time, it will have 3 standard nikasil cylinders, and I plan to set carbs to my 1200r carb settings....3/4 lows, 1.5 highs, watersocks on. My 1200r runs great with these settings. Any thoughts at all are welcome and appreciated.


  2. #2

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    You said rejetted, with what jets, needle sest, spring, and flame arrestor? Surging at top end is lean, drill restrict or mod done? Did you not have a 800 doing the same with same results?

  3. #3
    butterbean_29512's Avatar
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    It is jetted exactly to the recipe. The 800 belonged to someone else, I just commented on it. I ran it through some seaweed, and limped it back to the dock. It likely iverheated, and surged after I cleared the intake out. It seized shortly after during the next ride.

  4. #4
    butterbean_29512's Avatar
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    Update, pulled engine apart. It was in fact overheated. Also, I used SBT pistons, which have the internal snap ring pin retainers. Had 3 broken, did not find any pieces of them. Had a previous lean condition which lead to a meltdown, and the snap rings broke in that instance also. I AM DONE WITH SBT PISTONS!!!!!!! The steel wallows out the slot in the piston, and will eventually break. From now on, it's OEM or WSM pistons.

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