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1978 XS650E Standard - Consistent Whining Engine Sound

Discussion in 'The Garage' started by authenticnovelty, Jan 27, 2019.

  1. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    Based on the engine scenario (sound started in operation, not after an incorrect stator install), your stethoscope probings, and info gleaned from the linked threads, this is looking like bad crankshaft and main bearings. Leaking left crank seal could be a clue.

    The engine has to be torn down. Inspection of top-end parts, camchain and guides. Then pull the crank. Clean the crank bearings, and spin them, listen. Check crank wheel spacings. Also note condition of bearing alignment posts in the upper case...
     
    authenticnovelty and gggGary like this.
  2. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    This has popped up on a couple 75s, but XS cranks have lead? plugs that are poured into holes in the flywheels, one can come loose, and rub on the crankcase.
     
  3. authenticnovelty

    authenticnovelty XS650 Enthusiast

    Thanks guys. I've not detected any significant oil symptoms inside the generator area or anywhere inside the left case cover. I decided to ignore the oil leak as it really only amounts to a half dollar size spot on the pavement coming from my side stand mount. Would love to find it though.

    I am actively seeking a local space I can tear the engine down to examine and allow time to order parts. I suppose aside from pulling the rotor it is pretty unanimous that the engine's gotta come out one way or another. Will return with an update if any progress is made.
     
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  4. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    authenticnovelty likes this.
  5. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    there yah go; 2m straightens out my pour :cheers: memory. Shouldn't be an issue on your 78 or any other 447 motor. When cranks spread they are also likely to twist? hence our questions above about woobles at the ends. I have the forum distinction of the worst crankshaft wobble ever seen, LOL there's a poor quality video, the still assembled motor languishes in the shed, it was the original motor in Resto, a 79 showing about 20K, with an unknown past.
     
    Last edited: Feb 4, 2019
  6. authenticnovelty

    authenticnovelty XS650 Enthusiast

    After great deliberations I finally pulled the engine last weekend. I recently bought a timing light and realized I may also have timing issues related to this potential cam chain problem and decided it was time to just do it.

    Some of the conversation relating to the timing issues have crossed over into another thread: http://www.xs650.com/threads/cannot-stop-throttle-shaft-seal-leaks.54366/ (for reference), but I'm planing to focus on issues related to opening the engine on this current thread.

    The cam chain guide was destroyed as everyone had predicted. with several 3" chunks resting in the bottom of my engine case and a 0.5mm groove worn into the bare aluminum of the guide at this point. I also had a thick aluminum paste in my side filter, compared to the very small chunks of black plastic scattered on the last few oil changes. I think the timing chain appears to be okay, but I'm going to replace it with the guide. I think I can keep the tensioner in its current condition at the recommendation of 5twins.
    CFA69256-F05D-4EE7-902D-665E76599735.jpeg ED9F994C-679A-4FEC-93FE-A7E124432740.jpeg B3572204-3A4E-4124-BF58-3C348DE37E3C.jpeg IMG_B697DCE1B9F1-1.jpeg 87623397-E91A-4A56-99EF-732AF84D41DF.jpeg

    I honestly agree that most of my abnormal noise was the cam chain grinding into the guide/rolling across the broken chunks of plastic from it. While I have the engine open, I plan to give it all a once over though. Things seem fine as far as I can tell, but I'd love any advice I may have missed researching other threads on wear limits and replaceable items.

    Rockers - Seem good. They are smooth to touch, but have discolored spots on them. Pulled and shined with #0000 steel wool. They appear to match the spec of the Clymer book. In this photo is one as found and one after I cleaned. Does this seem okay? I've had valve clatter that seems to come and go just as my engine timing. I'm assuming the new chain will fix that without replacing the rockers or cam?
    IMG_DBD76920DFCB-1.jpeg

    Camshaft - Scratched, but I think just standard wear, not damaged. They are smooth to the touch. There are no deep scratches or pits on any of the surface. Bearings seem fine. First photo is "as pulled" and the second photo is after doing a light once over with the steel wool on cams only. The book says the spec for the cam shaft is
    Standard Value:
    Intake: 39.94-40.04mm || Exhaust: 39.98-40.08mm
    Wear Limit:
    Intake: 39.84mm || Exhaust: 39.88

    Mine measures 39.8. My caliper only does single digit decimal. Is it recommended I take it for evaluation/more refined measurements or is it likely fine?
    IMG_2DEE9AB6E086-1.jpeg 57629734398__08F72F33-86CA-45AF-8225-971A71160E7A.JPG


    I have removed the valves, but not fully cleaned or measured yet. Hope to have some details on those and pistons soon. is it necessary to put the valve springs in a spring pressure gauge to check or is just measuring them sufficient? Also, I see Mike's sells and suggests valve shims? should I get a set of those while rebuilding? I'm assuming those just compensate for loss of spring pressure? My cylinder compression has seemed fine so far, with both matching just under 130 and just under 150 with 1tsp of oil added.

    Hoping to soda blast the three pieces of the top end this weekend. Once I have all my ducks in a row up top, I plan to do a less invasive once over on the bottom end to cover my bases while out. I replaced the shifter shaft seal a week before pulling the engine and the case seal on the clutch side cover during last oil change, but It seems to have oil buildup on both frame bars under the engine after a few weeks of riding. Pushrod seal and crankshaft seal behind the rotor both seem fine? Not sure if the seal on the front of the crank case is leaking?

    Any insights to share on any of the above would be greatly appreciated, as I don't yet have the hands on experience to judge part conditions beyond the manual's written notes.

    Thanks in advance!
     
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  7. gggGary

    gggGary Stop that! Top Contributor XS650.com Supporter

    I guess my comment is that could be the aluminum in the oil causing smearing. Be sure to open, solvent clean, and blow out your oil passages, oil feed tube. Same with any bearing you can get to. No air spinning! Open, check the oil pump too. Do some of the wear checks of rod bearings?
    Were I looking at those parts I might be checking CL for a good used motor. Before reuse I'd likely run cam faces, rockers on the buffing wheel, that tends to do a good job of smoothing AND showing up wear, grooving. Rockers and maybe cam are hard surfaced? Back together, plan on a couple of quick oil changes.
     
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  8. TwoManyXS1Bs

    TwoManyXS1Bs BBQ Hunter Top Contributor

    In the dealership shop environment, that engine would be thoroughly torn down, cleaned, and inspected. That cam and rockers would be replaced, as well as everything camchain related.

    That's the harsh rule.
    Then the grey area, the engine will run with that cam and rockers, a bit under optimal, and may produce a bit more top end clatter. Not a pending catastrophe, just a grey area compromise.

    Roll the crank, feel for roughness/grittiness check the rod side-wiggle. You may be able to clean and peek into the rightside ball bearing, looking for rough surfaces, like this pitting.
    RightBearing.jpg
     
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  9. MaxPete

    MaxPete Life with Lucille...I suggest, she decides. Top Contributor XS650.com Supporter

    Agree with the above - perhaps a solid used engine might be a better bet.

    Your front guide must have been running bare (no plastic runner) for quite a while. My gu8de failed, but there were virtually no marks in the metal shoe.

    Pete
     
    Wulfbyte likes this.
  10. authenticnovelty

    authenticnovelty XS650 Enthusiast

    I'm in the home stretch. I've finished rebuilding the engine. Aside from the cam chain system, everything was in spec and fine according to cross reference of both manuals. I split the crank case soda blasted everything and replaced all the seals and copper washers. Also replaced the timing advance weights and #4 starter gear. The engine is back in the frame and I'm slowly connecting everything up as weather permits.

    I replaced the Cam chain, the tensioner arm and the guide. After reassembly my cam chain tensioner rod no longer fits. It sticks out too far and the cap nut will not close down to seal onto case. I've done thorough research on the forum to confirm it is a D style tensioner without a locknut and the correct tensioner for the engine. The listing for the chain on mikes says:

    "Cam Chain Endless - 219FTSS x 106. Pitch .3061" (7.774mm.) Fits: TX/XS650's 1974-84 (36 tooth cam).

    Made in Japan.Also fits: SR500 E/F/G/H 78-81, XT500 C/D/E/F/G/H 76-81 Dual Sport - Installation Note: Cam Chain is absolutely correct as original brand/size/length/type The installation will be tight as chain is pressure injected with grease at factory and head gasket is not yet compressed. Install with tensioner assembly out. Chain will loosen once head is torqued and engine is run a short time. Adjust cam chain accordingly."

    When I get everything back into the frame and wired up, Is there any advice for best procedure for first run? Should I just initially disregard the cap nut and set all of the timing and adjustments where it fits best and progressively adjust, run, cool, repeat until a consistent setting allowing cap nut to seal is found?

    Thanks in advance!
     
  11. 5twins

    5twins XS650 Guru Top Contributor

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    Yes, a new cam chain is very tight but I've never heard of it holding the tensioner out too much. Are you sure all your tensioner parts are type D, in particular the plunger? It's possible someone swapped in the later longer type E plunger because the old chain was so stretched and they were running out of adjustment. Here's the two tensioner types compared. The head on the type E plunger is longer .....

    [​IMG]

    [​IMG]
     
  12. authenticnovelty

    authenticnovelty XS650 Enthusiast

    Sorry, I think i may not have phrased it properly. I can get the cap nut to seal, but the threaded column has to be entirely bottomed out in the cap nut to the point where it continues to spin with the cap nut as tightened into plate. I initially considered the possibility of PO removing the lock nut of an E style to compensate for a stretched chain, but after seeing your previous post with the above info, i measured all the parts shown above in comparison with yours and all parts on the tensioner are full D style. Mostly just curious how normal this is and if any precautions to take on initial startup of a new cam chain and how long it should be run to stretch properly.
     
  13. 5twins

    5twins XS650 Guru Top Contributor

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    Well no, I don't think what's happening is normal at all. At least I've never encountered it before. But, I never installed a brand new rear tensioner blade either. I always just re-used the originals which obviously had some wear on (or into) them. Maybe that unworn new rear blade is what's making things so tight. If the acorn cover nut turns the adjuster screw in as you tighten it, that's going to make the chain adjustment tighter. Have that adjustment too tight and it will wear and stretch out the chain faster. Maybe you should temporarily fit a washer under the acorn nut, until you run it a bit and the chain loosens up some.

    The possibility of the acorn nut tightening your adjuster screw more as you tighten it down is the whole reason we upgrade these type D adjusters to type E's. One more thing you could check is the length of your adjuster screw. For a type D it should be 60mm long .....

    [​IMG]

    I would also make sure you have the proper 2mm thick copper damper washer and not the later "improved" 3mm thick rubber/metal type .....

    [​IMG]
     
  14. xjwmx

    xjwmx XS650 Guru Top Contributor

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    For future reference, I think listening with the cam chain tightened and loosened to the extreme would confirm or eliminate the chain, guides, as the problem. If it didn't affect the sound of the whine, it's coming from elsewhere.
     
  15. joebgd

    joebgd XS650 Addict

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    With the different total length of plunger piece due to the head, if the earlier one is shorter and the later one is maxed out when the plunger is flush with the screw wouldn't it be that the earlier shorter plunger would not tighten as much when flush? Unless the guide is different in some way to make the difference.
     
  16. authenticnovelty

    authenticnovelty XS650 Enthusiast

    Latest update: As previously mentioned, all parts are confirmed standard D tensioner. Got it up and running, sounds, feels, *seems* best since probably before I bought it. All odd noises have stopped. I'm convinced that the whirring noise was actually the cam chain rubbing against the stack of tall guide plastic resting at the base of the engine and the valve clatter and drifting idle was from the stretched timing chain. I have also managed to let the engine idle and do a several miles of riding cautiously at 2500RPM or lower (not hard in Brooklyn neighborhood traffic) to cautiously test it all out. The new chain has now stretched enough that I've needed to readjust the cam chain, valves and timing and the tensioner cap nut is seating fine again.

    Newest Issue: I can't get the timing correct on the right cylinder. Both points are currently at .016" (have tried a range between .012" and .018" with similar results. My right cylinder timing plate is rotated completely counter clockwise and cannot go any further. Setting it static with a multimeter I cannot get the points to close on that cylinder near the fire mark and with a timing light attached, the cylinder fires between the Fire mark and Advance mark at idle. Rotating the left point timing plate I can successfully get the left cylinder to hit the fire mark. For initial testing purposes it's pretty good overall, but the left cylinder (correctly hitting the fire mark at idle) will begin backfiring through the carb into the airbox when I try to raise RPM above 3000RPM. My TDC, Fire and Advance marks were set correctly on the rotor and engine case with a dial indicator and degree wheel while rebuilding the top end.

    I believe I've managed to install the camshaft one tooth out of alignment, counterclockwise from the crankshaft TDC. When the rain finally lets up this week, I'm hoping to re-test the intake valves with a dial indicator and degree wheel, as noted in the clymer manual to confirm. I wanted to send out a progress report and see if any additional words of wisdom to review before I revisit the situation and potentially pull the engine again this weekend.



    First kickstart after completed install. :D


    Thanks
     
    Last edited: May 13, 2019
  17. 5twins

    5twins XS650 Guru Top Contributor

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    You should be able to verify the correct cam timing by setting the motor at TDC then observing the locating pin (or it's hole) in the cam for the advance unit. It should point straight up or straight down .....

    [​IMG]

    No need to pull the advance housing off, you'll be able to see the pin or hole with it installed. It just happened to be off when I took this pic.
     
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  18. authenticnovelty

    authenticnovelty XS650 Enthusiast

    Thanks 5twins! I know that pin well... I lost it (the only missing part) during the reinstall and had to wait a week to get one shipped from mikes before I could actually start the bike :lmao:. I'll take a look at TDC asap and report back. That method requires a lot less effort to compare.
     
  19. 5twins

    5twins XS650 Guru Top Contributor

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    Yes, that pin (or it's hole) will face straight up or straight down, depending on which cylinder happens to be at TDC of it's compression stroke. The cam rotates at half speed compared to the crank. If the pin is facing down, give the motor another full turn to TDC again, and then the pin will be facing up.
     
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  20. authenticnovelty

    authenticnovelty XS650 Enthusiast

    Hmm... I can see the pin behind the advance unit at TDC every other rotation as described. it looks to be straight up at TDC. I haven't taken the advance unit off, but It looks pretty clear to me. I'm assuming a cam chain link off would put that pin more than 5 degrees one way or the other from straight up? Is there something else that could cause this phenomenon, if not the timing chain? I had mentioned having trouble with setting these points previously, but I can't understand why the main timing plate would need to be so dramatically shifted to get a basic timing.

    EDIT: rain is holding off. Dug a bit deeper. here are photos with the advance unit removed and the points/rotor while in position for reference. Also image of the process setting TDC (before applying degree wheel and marks during build.
     

    Attached Files:

    Last edited: May 13, 2019

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