BMW F650 Funduro ADV Build

Discussion in 'Some Assembly Required' started by donteatmyfood, Jul 30, 2020.

  1. donteatmyfood

    donteatmyfood The Better Idiot.

    Joined:
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    I must be completely out of my mind to take my functioning BMW F650 Funduro and tear it down to rebuild it. What’s not to love about this bike? The high fender? The stickerbombed brushguards? The truck-mud-flap bash guard?? All perfectly acceptable mods to bomb around in the mud!

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    But it wasn’t good enough. The Funduro was not really meant to be an offroad machine. Slightly modified from the normal F650 with a 19” front, taller suspension and longer wheelbase, it still was a porker at 421 lbs wet. I felt like a lot of that was coming from the fact it was adapted into an early form of adventure bike, rather than being built that way from the ground up. So I thought, I have another bike if I want to ride, why not try to improve the Funduro in better ways than the ADV equivalent of Tek-screwing a wing to a Civic.

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    I have two main goals with this build. First, I wanted to improve its offroad capability. Second, I wanted to do this while spending a fraction of what it would cost me to find one of its well sorted F800GS grandchildren. As I would expect to pay about $10,000 for a bike like that, I intend to stay under $3,000 total spend on parts and any labor I may need as part of this build.

    To improve its offroading capability, I am making changes to the following:

    Suspension Upgrades

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    I am changing the entire front end to that from a Cannondale X400. Originally I was going to do this with YZ450 forks and wheel, but a friend offered the X400 set to me for a very good price and it is NOS, in excellent shape. Added bonus is the 21" front wheel. I would love to retain the original brake setup, that may get added to the build. The rear shock I am upgrading to a shock from a F650GS Dakar, as well as adding to the top shock mount to increase the ride height.

    Reduced Weight

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    As I said before, the F650 wasn’t originally dirt oriented but was configured that way. But the weight of the machine bothers me. So I am “adding lightness” where I can. I am removing the 13-½ lb stainless steel exhaust in exchange for a much lighter slip on. The heavy dash, fairing frame and glass headlight are being replaced with a Trailtech Vapor mounted to a Nav-tower style dash that will also be holding Hella HB3 High and Low projectors. I may go with an Antigravity battery, but may just stick with an AGM to keep costs down. The other side of this weight saving is so I can add things like a proper bash-guard and possibly crash bars (again, cost) Though it is not much weight saving, I also wanted to reduce complexity by changing out the original dual carburetor setup with the single carb from the Bombardier DS650 that shares the exact same Rotax motor as the F650. This also means I am doing away with the airbox, but I am still working on how to provide both filtration and protection from water crossing.

    Improved Cooling

    I intend on replacing the heavy, original steel (copper/brass? its big and heavy and I don't know radiators...) radiator with a lighter aluminum split radiator. The original was very wide as well and vulnerable to puncture if I would go down on the trail, though I don’t know which radiator I am choosing for this yet, to adapt to the F650 frame. I am also planning on adding an oil cooler, as these bikes tend to run pretty hot. The more cooling I can provide, the better.

    [​IMG]


    At the moment, the bike is almost completely down to bare frame. I need to finalize some design choices before I can make any frame modifications. From there it will be putting it back together. If you are a fan of Instagram you can follow along with #MPPFunduro as I work on the build where I can. I’ll try to do periodic updates here as I make progress. I have a very bad habit of not finishing projects, but I promised myself I would finish this one! I am really excited to do so and hope to submit it to the local bike show Garage Brewed for 2021, so that’s my deadline!

    [​IMG]

    Thanks for reading about my build! Follow #MPPFunduro on Instagram or keep checking back on this thread for updates!
    #1
    airhead_irl, Pezz_gs, Hay Ewe and 7 others like this.
  2. Gedrog

    Gedrog 1000 mile stare a 1000 stories to tell

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    #2
    donteatmyfood likes this.
  3. GonzoMD

    GonzoMD Adventurer

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    Apr 7, 2020
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    50
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    Temecula CA
    That cannondale setup is a crazy find. You’ll have a one of a kind ride for sure!
    Question: I’ve never heard of a “steel” radiator, copper/brass maybe?
    #3
  4. donteatmyfood

    donteatmyfood The Better Idiot.

    Joined:
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    That's more likely. It was a guess, its painted black and that makes sense. Steel wouldn't last! :fpalm
    #4
  5. donteatmyfood

    donteatmyfood The Better Idiot.

    Joined:
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    Cincinnati
    So a good local friend was browsing the Flea Market and sent me a link to @bowtie39 selling a Funduro slip on exhaust. I was thrilled! It finally arrived yesterday and I test-fit it on the frame. I don't know what I was worried about, it was designed specifically for the Funduro after all. Fit great! May need a little trimming if I keep the tail as-is, but otherwise perfect!

    [​IMG]

    Its not as light as another one I had in mind from Ebay at 4.5 lbs, but it is still lighter (OEM goiter of an exhaust is a massive 13.4 lbs) and in excellent shape. I was very confident it would fit and was cheaper than the eBay version.

    [​IMG]

    Thanks again Roger!
    #5
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  6. gmk999

    gmk999 ____ as a Rotax

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    Following.. I have a '99. I absolutely love it but it really really needs a diet.
    #6
    donteatmyfood likes this.
  7. Rufjeep

    Rufjeep Been here awhile

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    Blue Ridge, GA
    Watching this. I've got an Aprilia Pegaso that's been sitting in my garage for years waiting for some love. It's very similar to the Funduro/ shares many of the same parts.

    If you look at the lines of those bikes with the tank/ seat/ fairing off, they really call for a diet and a makeover. You are definitely on the right track, and I can't wait to see how it ends up.
    #7
  8. donteatmyfood

    donteatmyfood The Better Idiot.

    Joined:
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    I considered an Ascot tank like they used on the Red Hot Chili Customs F650 but it also needs modification to my seat and I was trying to keep things simple. Might explore it again, it would solve the tank "ears" rubbing on the bigger forks. Less fuel though, it holds less fuel than the stock tank. But i could also carry a Rotopax. Hmmm...
    #8
  9. AlfromNH

    AlfromNH Been here awhile Supporter

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    NH, USA
    Count me in as another excited to see where you go with this. I like my Funduro but there's no question there's plenty of room for improvement!
    #9
    gmk999 likes this.
  10. Andyvh1959

    Andyvh1959 Cheesehead Klompen Supporter

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    Da frozen tundra eh? 1.5 mile west of Lambeau
    Interesting challenge. The Funduro (who at BMW picked that name) is a great engine, in a great frame, but hit with the ugly stick styling. I've always wondered what a piped F650 might sound like.
    #10
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  11. Pathfinders

    Pathfinders 1

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    LOUD like a 650cc chainsaw. The guy I bought this 1997 Funduro from installed a Dominator R, had it rejeted and slapped a 54 tooth rear sprocket on it. Back tire would lock up on down shifts. On the up side you could bring up the front end in the first 3 gears. Sprockets are now back to stock. I will be following this thread.
    15982205378233417596040016298010.jpg
    #11
    gmk999 likes this.
  12. donteatmyfood

    donteatmyfood The Better Idiot.

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    I almost bought the Dominator, it was on my list. I found an alternative on the Flea Market that was a better price. Not as light, but still much lighter than stock.
    #12
  13. Roadracer_Al

    Roadracer_Al louder, louder, louder!

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    Optimism and show aspirations, I'm in!
    #13
  14. WCPnCOSCOUSA

    WCPnCOSCOUSA n00b

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    I just bought a F650ST to refurb over the winter, keeping it stock. Doing a lot of searching for parts / suppliers and tech tips. Good luck with the big makeover of your model. Wheel bearings and carb kit on order, but why is it so difficult to find a perfectly ordinary supply of exhaust port ring gaskets? Anyone know of a identically sized part offered by a more popular make? Ordering from the UK is, er, funny to say the least!
    #14
  15. gmk999

    gmk999 ____ as a Rotax

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    Are the parts you are referring to the graphite tube type gaskets that fit the exhaust sleeves? I get mine at the local(wish) BMW dealer. And though I do not love to deal with them. These parts are cheap enough and in stock. So I don't feel that I need to look for a deal
    The dealer is Max BMW Brookfield Ct.
    #15
  16. Roadracer_Al

    Roadracer_Al louder, louder, louder!

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    A couple months ago, I got this, admittedly, very strange itch to build a custom F650c -- it has the funky cool single-sided swingarm and belt drive. Skimpy little tires, though.
    #16
  17. WCPnCOSCOUSA

    WCPnCOSCOUSA n00b

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    My neighbor told me of MAXBMW, seems like a good outfit. There have been complains on the graphite rings, so was hoping for copper substitute, but may just as well order them when I get something else from them. Thanks for the reference!
    #17
  18. mattomoto

    mattomoto 2 wheels rule

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    Good luck with your rebuild. Keep us posted!
    #18
  19. tri650

    tri650 Been here awhile

    Joined:
    May 1, 2006
    Oddometer:
    458
    Location:
    St. Louis, MO
    I have a 99 funduro and it has been my winter project. Bought for $200 so you can imagine the condition. Basically only needed carbs cleaned and rebuilt to get it running. Went from back to front replacing/updating/rebuilding everything with fluid - front/rear brakes, front suspension, rear suspension, coolant, etc. Bike runs great but wondering about a little hesitation under 4K. Thinking may move needle clip or find a needle with a different taper. Otherwise figuring what else I need to do to get it adventure worthy.
    #19
  20. gmk999

    gmk999 ____ as a Rotax

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    Anyone know what the silverfish paint color is on the engine parts /swingarm, hand grabs on the rear of the seat? And or where to get it? It's time for a repaint
    #20