Super Sherpa thread

Discussion in 'Thumpers' started by AZstrommer, Sep 3, 2007.

  1. Pencilpusher

    Pencilpusher n00b

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  2. Windborne11

    Windborne11 Been here awhile

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    On what engines are valves lubricated by oil pumps? Zero.... Valves slide through bronze valve guides which is inherently slippery. A small amount of oil will make its way past the valve seals but due to the bronze guides, very little oil is required.
    You need to get off this idea of the valve getting hot. This could happen on a multi cylinder engine, 4 - 8 cylinder design, but on a single cylinder engine, long before the valve got hot enough to burn, the engine would lose compression and fail to start or run. On a multi cylinder engine, the other cylinders with good compression could keep the engine running, though not very well.
    Overhead Cam journal seizures have been going on forever, I have replaced dozens of heads over the years for this problem, and the pistons did not score on any of them. Pistons are lubricated by oil splashing off of the crankshaft onto the cylinder wall.
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  3. AngryHandyman

    AngryHandyman Adventurer

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    I've given up on finding used parts and have placed an order for OEM parts to rebuild the top end from my local Kawasaki dealer. Cylinder head assembly, valves, seals, rings, various bolts etc. I carefully cleaned up the exhaust cam with fine emery cloth, measured both cams at all points and they're all within spec and look good so that saved me quite a bit of $$. While I'm at it, I've ordered a #30 pilot jet and air cover that was hair line cracked for the carb, which together should help with the Sherpa's cold starts. Some parts are back ordered into October, so it'll be a few weeks yet before they'll be available but I'm pretty happy with the pricing - surprisingly the cost came in CAD under the USD list prices I was seeing online at the usual sources.

    I'm looking forward to getting going on this, I didn't want to see this bike tossed for parts!
    1stgenfarmboy, thewbee, OU812 and 3 others like this.
  4. gibbo-56

    gibbo-56 Adventurer

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    I’ve been reading with interest the debate on the cause of your engine failure Handyman. I’m not sure I totally agree with either side but will throw in my 2 cents worth. Lack of oil alone I don’t believe would have caused it, and in my opinion valve clearances alone is also an unlikely cause. However to get enough force to break the cam bearing cap I think that valve stem seizure in the guide was also insufficient friction to lift the cam up through the bearing cap.
    As someone has already suggested I think that the cam timing had to be out, the only way this is possible is if the cam chain becomes loose and jumps on the sprocket, a one tooth jump may have been enough for your loss of power initially but a couple of teeth more and the piston is pushing up on that valve whilst the cam is trying to open it. I believe this caused your failure.
    So this brings us to how could the camchain jump? The cam chain tensioner is a very sophisticated bit of gear, I know I’m a bit slow but I need the manual to get reassembly correct whenever I have one off.
    I have some experience with the Sherpa as my partner has been riding hers around the world for 13 years and to date has some 320,000km yes that’s 200,000 miles. Swapped out the first motor at 250,000km only because it was consuming a lot of oil and with out any workshop facility I dropped in a $399 eBay engine which has done the rest. By the way neither engine has ever had the cylinder head off, and I have done all the maintenance on the road, never been in a workshop.
    So I digress but threw that in as there was some discussion on the longevity of these engines.
    I have, on 2 occasions over the years heard an irregular rattle in the engine and suspected cam chain slack, I removed the tensioner, found nothing untoward on both occasions reassembled and all was well. Now I don’t know why but I do know that for some reason unbeknown to me the tensioner can fail to take up the slack. I now have a manual tensioner which I will fit at the first sign of chain rattle, a loose cam chain is a disaster waiting to happen.
    So this was just my opinion to suggest you pay close attention to the tensioner on reassembly and always be on the lookout for that telltale rattle that could spell disaster. I won’t go as far as to suggest you fit a manual tensioner as I’m aware my issue may simply be due to the very high mileage.
    Good luck getting it back together.
    Cheers Gibbo
  5. travellingtenor

    travellingtenor Adventurer

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    200,000 miles! Wow, I don't have that much mileage on my Goldwing. Everything that I have read on the little Sherpa has stated that the bikes are generally very reliable. I hope that it is true. I would like to keep my Sherpa for a long, long, time.
    tlrmark likes this.
  6. 1stgenfarmboy

    1stgenfarmboy The Sherpa Man

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    Gibbo......I have read about the Sherpa you guys have ridden around the world.and have told countless people about the miles on the Sherpa under your care.

    Mine still smells new with only 20,000 miles compared to the Sherpa your partner rides.
  7. AngryHandyman

    AngryHandyman Adventurer

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    Thanks for the insight. To the best of my recollection, the cam chain tensioner didn't appear to be loose or have any slack in the chain and cam gears on disassembly, and I don't recall any rattle but I will definitely keep that in mind during re-assmbley. I appreciate all the input and ideas from everyone.

    Cheers!
    tlrmark likes this.
  8. inroads

    inroads Go West old man

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    Hello,could someone with a service manual please inform me of the Sherpa carb float height setting ??
    Thanks !!!
  9. Give 'er

    Give 'er Adventurer

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    14.6 +- 2mm
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  10. NWRambler

    NWRambler Been here awhile

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    Big trips on the RE-Strom and the new to me DR650 so far this year. And a not so brief affair in Utah with a WR250R (it's complicated). Not a lotta time on the Sherpa though . But it's headed to the desert with me soon. So, busy week:


    Cogent DDC's in the fork. And new oil, of course. Really looking forward to proper testing.


    Gearing went down one tooth in the front and down one in the rear with an aluminum sprocket. So, a more modest drop, and lost 1 pound of unsprung weight going with AL. That's the closest thing to a suspension upgrade the back of this bike is likely to see.


    While I was doing the drive sprocket, I fabbed up a seal retainer for the countershaft. There are two unused, blind 6M-tapped holes at about 4 o'clock. Very convenient. Prior seal failure is part of how I got my Sherpa for $500. I'd rather it wasn't how I lost it.


    That new DR got a big plastic tank and donated it's stock 3.4G tank to the green bike. An extra gallon in the Mojave can really make your day.


    The DR is loaning it's Pivot Pegs to the effort. Most kind.


    The BST took a Pine-Sol spa. Squeaky clean and a minor jetting tweak I've been putting off. Fastest start I've ever seen on this bike right afterwards. Cold day too.


    The seat gained some foam. Just scraps I had around. Pulled the Staples, added a small area of ½" foam and a ⅜" piece twice as big over that reaching further fore and aft. Pulled the same vinyl right back over. Less for comfort, more to give me a little height where I spend most of my time. Thereby, hopefully, encouraging me to stand more. I bet I'm not done with this.


    And, lastly, I aired up the Tubliss. After maybe 10 weeks, they needed almost nothing.


    Should be good.
    IMG_20190929_124153.jpg
  11. MikeS

    MikeS Fur shur! Vamos! Supporter

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    Your rack; did you make that or is it available somewhere? Looks like it was designed for soft luggage like Mosko or Giant Loop.

    As an edit: The reason I ask is this rack was custom made for my Honda. I'd like the same rack on my SS.

    [​IMG]
    Singlespeed92 likes this.
  12. 1stgenfarmboy

    1stgenfarmboy The Sherpa Man

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    No bash plate in the desert ?
  13. NWRambler

    NWRambler Been here awhile

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    "Designed" is an awful big word for the hack work I do. But that rack has endured considerable abuse. Cheap, soft throw-over bicycle saddlebags of any sort, duffel on top, or a milk crate, or a couple bundles of firewood. It's 3/4" cro-moly for the main tube and 1/2" and 3/8" mild steel for the rest; scraps off the shop floor. Better pix back on pages 355 and 358 of this thread.

    There'll definitely be a plate on it. Had it off for a little cleaning while I was doing the rest. Might explore other plates options though. The stocker is a bit skimpy.
    1stgenfarmboy likes this.
  14. 1stgenfarmboy

    1stgenfarmboy The Sherpa Man

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    I wish I knew where mine came from, it was on it when I got it, I do know the guy that had it, I will see if he can tell me where he got it.



    IMG_20190316_120734010_HDR.jpg
  15. NWRambler

    NWRambler Been here awhile

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    That plate looks pretty good. I'd sure be curious if you do find out. I know some folks have used the Moose plate made for KLR650. But so far I've struck out trying to score a used one.

    And, what are those pegs you have there?
  16. 1stgenfarmboy

    1stgenfarmboy The Sherpa Man

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    I just heard from the guy who had it before me, he said a guy in Tellico plains TN had a couple made and sold one to him, so sounds like it's homemade but a nice job, I made the foot pegs.
  17. NWRambler

    NWRambler Been here awhile

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    Thanks for checking into it. Looks like good work on both your parts.
  18. 1stgenfarmboy

    1stgenfarmboy The Sherpa Man

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    Sorry I couldn't help you dude.
  19. NWRambler

    NWRambler Been here awhile

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    Actually, you helped plenty, by showing me those pegs. I'm going to make a set of those. I'm 6'; but the Sherpa sometimes makes me feel 6'6".
  20. C-Stain

    C-Stain Long timer

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    0A3C4463-5D2A-4A1E-B4BF-A18EECEC626E.jpeg 929186C6-A9A2-4790-92E0-29E53BE6C06B.jpeg

    I dunno. A couple of mods and I did OK. Depends on what kind of riding your son is doing. Those shots are of me racing Hare Scrambles... MX sections and Enduro. Mind you... Im scared of heights and didn’t jump the Sherpa...

    And for what it’s worth? I finished more races on the Sherpa than I do on my GasGas.
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