DisTech's DR790 build

Discussion in 'Thumpers' started by DisTech, Mar 16, 2013.

  1. nzrian

    nzrian Been here awhile

    Joined:
    Feb 20, 2009
    Oddometer:
    813
    Location:
    Queenstown , NZ
    :clap
    #21
  2. Reposado1800

    Reposado1800 Juicy J fan!

    Joined:
    Dec 8, 2006
    Oddometer:
    5,815
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    5th and Main
    I wonder how many people just use a punch to get that ring nut off.
    This is probably going to be the build thread of the year. I can't wait to see it go together.
    #22
  3. DualSport650

    DualSport650 Lucky Burglar

    Joined:
    Apr 21, 2004
    Oddometer:
    636
    Location:
    Bend, Oregon
    Oh, man.

    I gotta see this build!!! :eek1

    I wonder if I could 790 my Honda XR650R? LOL! :evil
    #23
  4. rch10007

    rch10007 Dotted Quad Ranger

    Joined:
    Aug 18, 2010
    Oddometer:
    39
    Location:
    Clarksville, TN

    I wouldn't suggest it. IF someone did get it off with a punch, they either tore up the nut and would lie about it or they are the luckiest SOB in the world or they are just plain full of shit. The first time I rebuilt a DR motor, I tried everything short of a blow torch to get it off. Finally, i broke down and bought the tool. I figure if I'm going to be rebuilding these things, it pays to have a good tool. It takes 2 secs to remove, replace and torque that nut with the proper tool. Who wants to risk f'n up a brand new motor over not having the right tool. I know we all like cheap, but sometimes, you get what you pay for.
    #24
  5. DisTech

    DisTech Been here awhile

    Joined:
    Sep 3, 2008
    Oddometer:
    643
    Location:
    Seattle
    I did whack the ring nut with a punch and hammer a few times, but it's pretty soft and was taking too much damage. So I stopped and searched for the proper tool. Judging by the amount of force it took to remove it, the ring nut would have been destroyed using a punch.

    Splitting the case for the 790 upgrade is not necessary. I'm doing it for three reasons.
    1. Last year I took my clutch apart too far and wrecked the little retaining wire that holds some stuff together that you normally don't touch. The old wire was consumed by my transmission... hard shifting... whining noises... etc...
      I replaced the retainer wire and flushed/cleaned it out as best I could and everything seemed fine, but it been nagging me as to what was left in the transmission.
    2. Check the bearings (see #1).
    3. Check if 3rd gear getting ready to explode!

    On with the case!
    [​IMG]

    Another special tool.
    [​IMG]

    All clear.
    [​IMG]

    Flip it and split it.
    [​IMG]

    It actually came apart easier than my 350's.
    [​IMG]

    And clean too!
    [​IMG]

    [​IMG]
    <table cellpadding="0" cellspacing="0" border="1"><tr><td>1</td><td>Countershaft/Gear, 1 St Drive</td></tr><tr><td>6</td><td>Gear, 5 Th Drive</td></tr><tr><td>3</td><td>Gear, 3 Rd Drive</td></tr><tr><td>4</td><td>Gear, 4 Th Drive</td></tr><tr><td>2</td><td>Gear, 2 Nd Drive</td></tr><tr><td>15</td><td>Gear, 1 St Driven</td></tr><tr><td>27</td><td>Gear, 5 Th Driven</td></tr><tr><td>21</td><td>Gear, 3 Rd Driven</td></tr><tr><td>26</td><td>Gear, 4 Th Driven</td></tr><tr><td>18</td><td>Gear, 2 Nd Driven</td></tr><tr><td>14</td><td>Drive Shaft</td></tr></table>
    The 5th drive gear has some minor spalling, but rest look fine.
    [​IMG]

    1. What remains from that clutch retainer wire? Nothing! :thumb
    2. Bearings are tight and free spinning. As far as I'm concerned they are good to go.
    3. Gears look good too. :clap

    I'm putting the case back together in the morning.
    #25
  6. DisTech

    DisTech Been here awhile

    Joined:
    Sep 3, 2008
    Oddometer:
    643
    Location:
    Seattle
    Clean an reassemble!
    [​IMG]

    Align the dots!
    [​IMG]

    Manual says position shifting cam like this so the forks will fit easily into place. It works!
    [​IMG]

    This was pleasing (can't do this with DR350 guts on thier side) and looked cool.
    <iframe width="640" height="360" src="https://www.youtube.com/embed/bXTZiFgqTtI?feature=player_detailpage" frameborder="0" allowfullscreen></iframe>

    Case sealed!
    [​IMG]

    Was cruising right along, then "What the...!!!" :eek1 (see arrow). Did I leave out a dowel! Frantic looking at pictures I'd taken, manual searching, Googling exploded views, nothing...
    [​IMG]

    Decided to push on and when I dropped the starter torque limiter in place it was super sloppy. Well, well... not a dowel, it's a sleeve.
    [​IMG]

    A big thanks to planemanx15 for having the guts to post the highs, lows and highs of his DR790 build (DR650 790 Big Bore Installation and Review) :clap.

    A couple things that have come from the lows:
    • I have been scared straight regarding proper ring gap!
    • ProCycle has this excellent walk-through, Gapping your piston rings.
    [​IMG]

    Notes:
    • Top ring is gray and has a dot indicating the top.
    • Second ring is black and has a dot (more like a circle) indicating the top.
    • The stock piston has a dot on it that indicates the front. The CP piston does not and their install instructions only talk about ring gap and cylinder honing. Eyeballing the piston makes me think it is symmetrical and can go either way and I would expect the instructions to say something if it mattered. However, I found one forum post that said the pockets were different and the CP on the bottom of the piston goes to the exhaust side. There is a CP marked on the bottom so I oriented the piston with the CP to the front.
    • The oil ring and its side rails were by far the hardest to get in the jug (without ring compressor).
    • Ring gaps positioned according to the manual.
    • The CP piston pin circlips are at least three times as beefy as the stock ones! A challenge to install.
    • Double metal base gasket!.
    [​IMG]

    Got the jug on and that's where she sits tonight.
    [​IMG]
    #26
  7. DisTech

    DisTech Been here awhile

    Joined:
    Sep 3, 2008
    Oddometer:
    643
    Location:
    Seattle
    One of the notes from ProCycle is that the manual has a typo. It's true, it does and I thought it was funny that it specifically tells you to put the bolts in the "correct position".
    [​IMG]

    New cam, old cam.
    [​IMG]

    TDC and line up the timing chain marks.
    [​IMG]

    Suzuki molly paste and Red-line grease.
    [​IMG]

    790cc!
    [​IMG]

    The gear shift cover gasket did not survive the procedure and a new one is on order.
    #27
  8. rch10007

    rch10007 Dotted Quad Ranger

    Joined:
    Aug 18, 2010
    Oddometer:
    39
    Location:
    Clarksville, TN
    Stock carb?
    #28
  9. refokus

    refokus Hmmmmmm

    Joined:
    Jun 7, 2007
    Oddometer:
    2,871
    Location:
    North Phoenix
    Nice work, keep it coming. I am interested in hearing the final results on the build. :clap
    #29
  10. DisTech

    DisTech Been here awhile

    Joined:
    Sep 3, 2008
    Oddometer:
    643
    Location:
    Seattle
    TM40, FMF oversize header and GSXR exhaust.
    #30
  11. DisTech

    DisTech Been here awhile

    Joined:
    Sep 3, 2008
    Oddometer:
    643
    Location:
    Seattle
    Thanks, me too!
    #31
  12. Bronco638

    Bronco638 Nobody Home

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    Dec 1, 2004
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    4,902
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    Itasca, IL
    Wait! You have Boss 302 heads lying around the garage!? Dude, those are some valuable weights.
    #32
  13. Chinookmark

    Chinookmark Been here awhile

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    Oct 13, 2005
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    304
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    New Hartford, CT
    :lurk
    #33
  14. plutonic

    plutonic Outsider

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    Sep 9, 2006
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    Location:
    Alpharetta, GA-Budapest, Hungary
    Any news?
    #34
  15. DisTech

    DisTech Been here awhile

    Joined:
    Sep 3, 2008
    Oddometer:
    643
    Location:
    Seattle
    I wasn't planning on replacing the linkage bearings because last time I was in there (few years ago on first build) everything seemed good and I greased everything thoroughly. Well the "Heavy Duty Axle Grease" that I used... lets just say it turned against me. So new bearings all around and Maxima Hi-Temp Waterproof Grease.

    Out with the old!
    [​IMG]

    Nice looking part when it's clean.
    [​IMG]

    Swingarm and linkage with new bearings & seals. Got the rear wheel back from the Wheel Master this week. Looks pretty nice, 18x2.5 Excel, heavy duty spokes, 520 sprocket and new bearings & seals. D606 130/90 18 is on order!
    [​IMG]

    New 18x2.5 rim next to old 17x4.25. Quite a difference!
    [​IMG]

    The gear shift cover gasket arrived today and is installed.

    Had some bad luck with the "good deal" I found on the fork springs. Actually had to file a claim through Amazon to get a refund. I did get the refund but that has delayed things. Springs are on order again, this time direct from Race Tech.
    #35
  16. BergDonk

    BergDonk Old Enough to Know Better

    Joined:
    Nov 15, 2010
    Oddometer:
    5,299
    Location:
    Snowy Mountains Oz
    Interesting stuff. I see that you have what appears to be a non standard shock? Does it have any more compression than stock? If so, a 130 18 might be a little to large. With my Ohlins, a 120 18 606 is right on the limit with the chain adjustment in the middle, and even then, some damage resulted.

    [​IMG]
    #36
  17. DisTech

    DisTech Been here awhile

    Joined:
    Sep 3, 2008
    Oddometer:
    643
    Location:
    Seattle
    Thanks for the info BergDonk. It's a Cogent shock so if there is a problem then the 130 will be for my DR350.
    #37
  18. DisTech

    DisTech Been here awhile

    Joined:
    Sep 3, 2008
    Oddometer:
    643
    Location:
    Seattle
    Not knowing what I'm doing, this is how I secured the nav tower mount to be tacked into place.
    [​IMG]

    After LOTS of fiddle forking around trying to get it straight.
    [​IMG]

    Finally committed and it looks straight! :clap
    [​IMG]

    Masked.
    [​IMG]

    Rattle can black.
    [​IMG]
    #38
  19. DisTech

    DisTech Been here awhile

    Joined:
    Sep 3, 2008
    Oddometer:
    643
    Location:
    Seattle
    #39
  20. EBMOTT

    EBMOTT Adventurer

    Joined:
    Jun 28, 2011
    Oddometer:
    70
    Location:
    SANTA ROSA, CA
    Great build . I am interested to how frnt forks and rear wheal turns out. These are mods that i want to do.
    #40