2WD Fat Tire KLR 650 conversion

Discussion in 'Some Assembly Required' started by sdbryan, May 24, 2018.

  1. sdbryan

    sdbryan Adventurer

    Joined:
    May 24, 2018
    Oddometer:
    18
    Location:
    San Diego, CA
    I am so glad I found this forum. I am in the process of converting a wrecked KLR in to a fat tire 2WD. I mainly wanted something to wrench on and to learn a little welding along the way.

    The goal is to create a fat tire 2WD that I can easily cruise through the sandy washes in AZ. I got some smaller sprockets so I will be gearing this down quite a bit and don't plan on taking it super fast because my lack of engineering skills, slightly bent frame and who knows what else. It is mainly going to be a cruiser.

    To make the process easier, I am going to have a solid front end to start off with. I got a triple tree from a ATC 250R and attached the stem from the KLR and everything bolted up nicely.

    I was wondering if anyone has an idea if this aluminum triple tree will be strong enough for basic riding. The bike will be heavy when completed and compared to a 250R.

    Also, do you think I will need some type of freewheel sprocket or something to keep the chain from binding up? I was hoping just to run a chain from the engine to a jackshaft. One chain will then go to the front tire through a u-joint and one to the rear tire.

    And finally, are there sprocket type chain tensioners that I can use to keep everything tight with long spans of chain? Strong enough for a motorcycle?

    Thanks again, you can follow along and see the videos of the build so far at:



    Youtube channel: https://www.youtube.com/channel/UCrEdyFcfeDdmSys7cMCrkiw

    Thank again!

    Bryan
    #1
    JagLite likes this.
  2. JagLite

    JagLite Long timer

    Joined:
    Jun 17, 2010
    Oddometer:
    5,351
    Location:
    Anchorage Alaska
    Interesting!
    I don't understand your description of the front wheel drive system you plan though.
    I wouldn't worry about the strength of the triple clamps from the ATC since it was designed strong for jumping and typical crazy kid riding.
    As long as you are riding it more like a Tote Goat (slowly).

    I see you have a number of videos so I will watch them.
    Might be like watching a slow train wreck....

    [​IMG]

    I applaud your enthusiasm without worrying about how you will accomplish your desired result.

    Many builders suffer from AP (Analysis Paralysis) and never finish what they start.
    Uh, you don't happen to have any unfinished projects sitting around do you?
    Boat, go kart, camper, 4x4, house...
    #2
    Pezz_gs likes this.
  3. sdbryan

    sdbryan Adventurer

    Joined:
    May 24, 2018
    Oddometer:
    18
    Location:
    San Diego, CA
    I totally know about AP, I have to keep a max of 2 projects going at any one time when I would love to have maybe 10 or more. Space is limited around these parts, so I guess that helps.

    I really haven't ironed out anything with the front drive system. Hopefully will get the rear axle mounted this weekend so I can see where the jackshaft needs to go.

    But what I am planning is having a small chain go to a jackshaft with 2 gears on it. 1 chain will got to the rear and will have to be level with the rear sprocket so there is no problem with the rear suspension. The other chain will need to go along the lower left or lower right side of the bike, then up the frame to the neck where it will meet up with a u-joint and come down one of the forks to the front tire.

    Thanks for the feedback. I am sure it will be a train wreck! But that is what makes it exciting!

    I am going to do something like this for the front wheel drive.
    upload_2018-5-25_10-36-11.png
    #3
  4. phreakingeek

    phreakingeek adventurer

    Joined:
    Sep 17, 2010
    Oddometer:
    1,617
    Location:
    VA
    How would you turn the front wheel with this chain setup? Seems like it would be better to use a hydraulic system to allow you to route the lines from a pump to a drive motor and still be able to turn the front wheel.

    #4
    Pezz_gs and JagLite like this.
  5. sdbryan

    sdbryan Adventurer

    Joined:
    May 24, 2018
    Oddometer:
    18
    Location:
    San Diego, CA
    The u-joint allows you to turn. The gear on the right side of the above photo doesn't move and is fixed to the frame. The other side is fixed to the fork.

    I would totally love to have hydraulics, just couldn't find an inexpensive hydraulic system. I also don't really know much about hydraulics and if I could keep both wheels spinning the same speed easily. But that would have made the steering and front suspension much easier.
    #5
    JagLite likes this.
  6. JagLite

    JagLite Long timer

    Joined:
    Jun 17, 2010
    Oddometer:
    5,351
    Location:
    Anchorage Alaska
    Ah, I see, with the sprocket end of the shaft fixed to the frame and the u-joint under the steering axis it will work.
    Lots of limitations but it will work.
    You could examine how Rokon powers the front wheel for more ideas too.
    Your fat tires will be your suspension then.
    #6
  7. Beezer

    Beezer Long timer

    Joined:
    Oct 26, 2004
    Oddometer:
    8,192
    Location:
    Anchorage, formerly Spenard (hub of the universe)
    reminds of what the Chief said in "A Man called Horse".....

    "suffer much pain.... then see (the god) Wakentonka" :rofl :flip ha ha..... go for it

    PS ... also thinking of a vid I saw some time back with hillbillies racing riding mowers with hopped up engines. the one guy wins the race, waves his arm in victory & flops his hand down into the unguarded drive, promptly lopping off 3 fingers. it was friggin hilarious
    #7
    sdbryan and JagLite like this.
  8. sdbryan

    sdbryan Adventurer

    Joined:
    May 24, 2018
    Oddometer:
    18
    Location:
    San Diego, CA
    Yeah, I am going to make sure to make some serious chain guards!
    #8
    JagLite likes this.
  9. tntmo

    tntmo Oops, I did it again.

    Joined:
    Jan 31, 2012
    Oddometer:
    913
    Location:
    San Diego, CA
    If you're in San Diego, I'm willing to come by and offer bad suggestions while I drink beer or something.
    #9
    sdbryan likes this.
  10. vfrpilot

    vfrpilot Stress Relief Rider

    Joined:
    Apr 28, 2006
    Oddometer:
    1,018
    Location:
    Decatur, Illinois
    Yeah, I'm going to watch this ............


    cause I ain't never seen more potential for failure. :fall
    #10
    sdbryan and JagLite like this.
  11. shinyribs

    shinyribs doesn't care

    Joined:
    Sep 24, 2011
    Oddometer:
    1,926
    Location:
    The South
    Hey man, just found your thread and saw your video where you are dealing with the fork swap. If you run in to deadends getting someone local with a lathe to NOT rip you off, shoot me a PM. If you have a good set of calipers and can take good measurements I'd be happy to turn up simple spacers for you. I don't have a mill but I'd be lost without my lathe :D
    #11
    sdbryan, Pezz_gs and JagLite like this.
  12. tntmo

    tntmo Oops, I did it again.

    Joined:
    Jan 31, 2012
    Oddometer:
    913
    Location:
    San Diego, CA
    How long is that swingarm? You can compete with some of those drag bike Hayabusa's I see around!
    #12
  13. sdbryan

    sdbryan Adventurer

    Joined:
    May 24, 2018
    Oddometer:
    18
    Location:
    San Diego, CA
    There are a lot of times I could use a lathe, always trying to find work-arounds is a pain in the ass. I appreciate it and will hit you up! Thanks again!


    #13
  14. sdbryan

    sdbryan Adventurer

    Joined:
    May 24, 2018
    Oddometer:
    18
    Location:
    San Diego, CA
    Almost 4' Long of pure awesomeness
    #14
  15. sdbryan

    sdbryan Adventurer

    Joined:
    May 24, 2018
    Oddometer:
    18
    Location:
    San Diego, CA
    So, I am working on running the chain to the rear tire... So I have some questions...

    1. I ordered some keyed sprockets to go on my 3/4 jack shaft that were supposed to fit my standard KLR650 520 chain, but they are not good. Anyone know where I can find some sprockets that I can put on a 3/4 keyed jackshaft?

    2. If all of my jackshafts have the same size sprockets on them, and the front and rear tire have the same size sprocket on them, shouldn't the tires spin the same speed regardless of how many sprockets it runs through?

    3. any virtual / CAD places online where I can mock up my chain system? this really doesn't matter, just would help when trying to explain it to people.

    4. how expensive is it to double your life insurance at age 49?

    Here are some recent photos.

    upload_2018-6-3_19-4-1.png
    upload_2018-6-3_19-4-17.png
    upload_2018-6-3_19-4-30.png
    #15
    JagLite likes this.
  16. tntmo

    tntmo Oops, I did it again.

    Joined:
    Jan 31, 2012
    Oddometer:
    913
    Location:
    San Diego, CA
    Oh, I forgot to ask if you weighed that swingarm monstrosity as well? It's gotta be hefty.

    I want to hate this project, but I just can't. I see so much potential for failure, but I want to see this thing move under it's own power!
    #16
    JagLite likes this.
  17. Luke

    Luke GPoET&P

    Joined:
    Aug 25, 2004
    Oddometer:
    4,764
    Location:
    Beaverton, OR
    1: no idea, and I looked for a while. I ended up getting ansi #50 sprockets and cutting them down to the right thickness.

    2:Yes

    3: Likely easier to draw it out on paper and scan/photograph. If you don't really need it, CAD is a total time sink. Especially when learning it.

    4: Depends on whether they know you are screwing around with motorcycles.
    #17
    JagLite and sdbryan like this.
  18. dirt hokie

    dirt hokie Long timer

    Joined:
    Oct 3, 2007
    Oddometer:
    1,445
    Location:
    Eastern shore of MD
    McMaster Carr, they have everything
    #18
    JagLite and sdbryan like this.
  19. nk14zp

    nk14zp Long timer

    Joined:
    Feb 24, 2010
    Oddometer:
    1,286
    Location:
    Maine
    I think you should use a CV joint instead of a u joint.
    #19
    JagLite, scot_douglas and Roofchop like this.
  20. dbarale

    dbarale Squiddly slow

    Joined:
    Oct 20, 2008
    Oddometer:
    2,071
    Location:
    Western NC
    #2 is correct assuming you’re running the same size tires (at roughly the same pressure).
    #20
    JagLite and sdbryan like this.