Help me achieve perfection - WR450 twin Adv conversion

Discussion in 'Some Assembly Required' started by MotoPolo, Apr 22, 2016.

  1. Son of MotoPolo

    Son of MotoPolo Yay, mountains!!

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    So what's the slowdown? I'm missing the frequent updates. Don't tell me you have something more important to work on??
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  2. MotoPolo

    MotoPolo So many places, so little time

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    I guess I need to post an update. The slow-down is the seat/shock mount - I got as far as tack welding a whole system in and then took it out as I didn't like it.
  3. jays100

    jays100 Been here awhile

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    gosh, I missed some updates on my watched threads. Liking the direction this is going and how the cake is being baked (wait, did I just say that?). Like Sammy, I'm waiting to see what you come up with for the lower tube bracing.
    those pesky seats and shock mounts can sure be, will, pesky! I'm sure you'll find a great solution.
  4. MotoPolo

    MotoPolo So many places, so little time

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    Thanks Jays

    I'm having a bit of withdrawal myself. I think I have a good solution on the shock/ seat. I ended up with the frame (seat mount) inside the swingarm which required oval tubing to clear both the swingarm and the shock.

    I also invested in a like new 690 airbox - hoping that it would work - alas it is just a bit too big at the front. But it did convince me that that is the spot for the box and it won't be too hard to fab one. If your 690 needs a nice new airbox let me know - I just want to get what I have in it.
    Also I am looking for a 690 seat pan (or beat up seat) - maybe a trade?

    I also got my 520 drive sprocket - 14 T. For those looking at the FZ07 engine it uses the same sprocket as the Yamaha R1

    If anyone can confirm the amount of offset of the Yamaha WR 450 front rim relative to steering head centerline that would be helpful. I am about to send off my hubs to Woodies but need to decide what to do with offset. Based on Luke's experience I am inclined to have no offset up front and maybe none in the rear and just live with the front and back being a bit out of align. Appreciate any opinions on this.

    Been thinking about lighting - probably go with Baja designs squadron Pro - any other solutions you all like? My fairing has twin ports for 80mm lens. Nav tower will be carbon fiber. I'll make my own sheet, 2 ply on birch ply, probably about 1/8". If anyone knows what the Rally guys are using let me know - they seem to withstand some good crashes.

    I'll try to get some drawings posted
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  5. totensiebush

    totensiebush re-tarded

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    If you weren't aware the WR450 uses wheels compatible with a lot of Yamahas for a long time - basically all their watercooled 4 strokes until the YZ got a backwards cylinder.

    I wouldn't have expected any offset in the wheel vs steering head centerline...
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  6. MotoPolo

    MotoPolo So many places, so little time

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    here are some drawings of frame:
    Screen Shot 2018-03-13 at 5.39.27 PM.png

    I've shown all the engine mounts in this view (5). The item with red lines is the shock mount centered on a bent cross member and extending to pickup the shock mount on the engine (now used as an engine mount). This ought to make the shock mount pretty robust. The engine mount coming off the swingarm axle is a short pivoting arm picking up the closest engine mount. This is my one area of concern. Ideally this mount would capture two engine mounts so that it can't rotate. Traditionally it would extend to the lower engine mount (and I may still do that). The lowest engine mount comes off the link support cross member, that the member we were discussion on how to reinforce. The engine mount is a simple 3/4" dia tube welded to the front of the cross member and a short link over to the engine. That should dump all the load on the cross member into the engine as well as add some bending stiffness. The aft members "<" are the lower tank mounts. they also add to the stiffness of the link cross member. With some gussets (not shown) as the link cross member meets the uprights I think this area is plenty strong.

    Screen Shot 2018-03-13 at 5.39.55 PM.png

    This view (looking from behind the frame) shows the tank and shock mounts better. The center column members (in this view) are the aft members and they extend up to the shock mount crossmember. Those tubes are oval until they get above the spring and then they go back to round. The upper seat mount is a little hard to understand - if you are familiar with the 690 seat hardware it sits to the OUTSIDE of the vertical wall of what looks like a channel shape in this view.

    Screen Shot 2018-03-13 at 5.41.59 PM.png

    Top view might help clear things up a bit. I needed to bend the shock support cross member to get the support in the right spot. The colored parts are hidden tubes from upper seat mount down to the shock support cross member.

    Screen Shot 2018-03-13 at 5.35.20 PM.png


    This might help show it all. Very tight with shock and seat mounts inside the swingarm, thus the oval tubes
  7. tileman

    tileman Long timer

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    This is awesome. Hope it goes the distance.
  8. Son of MotoPolo

    Son of MotoPolo Yay, mountains!!

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    "The engine mount coming off the swingarm axle is a short pivoting arm picking up the closest engine mount. This is my one area of concern. Ideally this mount would capture two engine mounts so that it can't rotate. Traditionally it would extend to the lower engine mount (and I may still do that)."

    What's keeping you from doing this, what's the rationale behind splitting into two separate mounting arms? There looks to be enough room to fab a "Y" arm capturing both engine mounts and the swingarm axle.
  9. MotoPolo

    MotoPolo So many places, so little time

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    Great question and I'd appreciate some more discussion on this topic.

    That was my original plan, but as Jays100 pointed out the link cross member needs reinforcement. I added the seat mount structure which will stiffen that cross member quite a bit but wanted to also connect that member to the engine. Now I think that is a good design for that member.

    Similarly at the top shock mount I extended it to the engine. With a heavy weight penalty in this engine I want to get as much load carrying done by the engine as possible (vs the frame).

    So now with just the swing arm axle to the one remaining engine mount, I am confident the engine is well supported.

    The question is: Is the swing arm axle supported well enough with just the short link. My thinking is: "Maybe". With 5 engine mounts I see little chance the engine can rotate on the short links. The short link to the swingarm axle will definitely add considerable support to the axle - will it be enough?

    Options:
    1) Add a "Y" arm and double up on the lower engine mount - con: adds weight, takes more time to fab
    2) Extend axle support from upper rear engine mount to pick up engine shock mount (basically a beam with 3 supports), no rotation of this beam. - con: adds weight, takes more time to fab
    3) Build as shown above and see if more support is needed: Con? Can I hurt something? How will I know more support is needed?

    Looking for structural engineering feedback - thanks
  10. Whale Rider

    Whale Rider Been here awhile

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    Ha MotoPolo why don't you throw the linkage set up away and just put the shock straight from the swingarm to the frame didn't KTM use this method. Makes for a shorter shock and lighter.
    WR
  11. MotoPolo

    MotoPolo So many places, so little time

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    WR - Now you come up with that?!!!- we went by that milepost on pg 16 or so -

    Just kidding - it was a thought but I think even KTM concluded linkage is better - better to put the damping progression in the linkage than to build it into the shock. But to your point for an Adv bike it might work fine and would make for a less complex frame. For me part of the issue was finding a good donor swingarm. All the KTM swingarms with straight shock were too narrow.
  12. Whale Rider

    Whale Rider Been here awhile

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    Have you got a photo of the swingarm that you are using? What is to stop you using the swingarm that you now have with a straight shock?????????? Shock is a lot shorter and only needing about 80mm shaft travel for 250mm wheel travel
    depending on swingarm length and shock mounting point. Many manufactures still use with great success.
    WR
  13. Parx400

    Parx400 Long timer

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    The front is something like 1992 to the backward cylinder. same everything. The rear is 1999 up. 1998 had the older size rear hub/ axle.
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  14. scot_douglas

    scot_douglas Dirt Harley Lovin'

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    look back through the thread, he's posted pictures.
  15. MotoPolo

    MotoPolo So many places, so little time

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    WR

    You know I have a great technique for falling asleep each night - I think about all these fun design issues - last night, after posting my response to you I thought - "I bet I can just turn the swing arm over and use the link mount as the lower shock mount". I'll verify that for you.

    However - At this point I really like the 690 rear tank which would not work with a straight shock. The rear tank get the cg lower, replaces the rear subframe, and can be upgraded to a Rally tank with added capacity. So for now I'm going to continue with plan to accommodate 690 rear end.
  16. Whale Rider

    Whale Rider Been here awhile

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    MotoPolo just found the photo in post 414 and had a look. You don't even need to turn the swingarm over if you build a block that bolts through the lower linkage mount and comes up to same axle as the swingarm is mounted to it effectively becomes part of the swingarm and you could put a direct acting shock mount on anywhere along it to give the rear wheel travel you desire from a shock you choose to use. just a thought.
    Whats the distance back to the swingarm from the pivot point on the 690 before it goes solid?

    You know I have a great technique for falling asleep each night- I think about all these fun design issues

    Sh-t I don't do it while I am falling asleep I do in my sleep makes for some great solutions

    WR
  17. MotoPolo

    MotoPolo So many places, so little time

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    OK - now you got me thinking - maybe you could fit this in with the 690 tank - CAD is a great tool for this and I have all the dimensions right there
  18. MotoPolo

    MotoPolo So many places, so little time

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    Well that was quick - took a look at CAD - the stock fz07 shock has to be almost horizontal to not foul the engine cases - I believe they put the linkage on top of the swingarm.

    No way you could attach the shock below the swingarm and use engine shock mount

    Top mounted shock possible but not an option with rear tank.
  19. Whale Rider

    Whale Rider Been here awhile

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    I think that is part of the problem trying to find parts like the rear tank that you want to use and making them fit. Have you looked at BMW dare I say it F650 /850 tanks as they use direct shocks. But if you made the adapter a Y shape IE: bolts on underneath goes to the pivot point and on the top could go as far back as the roundy bit for the tyre and a short non linkage type shock and there is still not enough room
    Then good luck and I can't wait for your solution.
    WR
  20. Salsa

    Salsa Long timer

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    Be real careful, or you will be making 2018 shocks into 70's shocks.

    Be sure to go through your CAD geometry to be sure you can get some meaningful progressiveness in the shock.

    Don
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