1967/1969 Bonnie Rebuild Desert Sled Project - Any Advice

Discussion in 'Vintage Classics' started by Sundance, Sep 15, 2021.

  1. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    I’m working on my fork rebuild, needing to replace most everything. I have a spring question however. I understand the Yellow/Green painted springs are the heavy duty springs, and the Yellow/Blue painted are the standard springs. It looks like the springs from my fork are ? Green/Red? - or ?Green/Yellow? - or ?Green/Orange? I’m wondering if anyone can identify these? Thanks.

    IMG_2517.jpeg
     
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  2. darkman

    darkman Crème de la Crème

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    Looking at the green on the other spring i would say they are the HD springs.
     
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  3. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    I kind of think so also. I was planning to put in the stronger springs when I rebuilt them and thought this would have had the standard springs. Since these are 30-40 years old, I suppose I should replace them with the same - or I see that there are some progressive springs out there too. I was just wanting a bit more stiffness up front than normal.
     
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  4. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Another fork question: My forks are pretty beat up. I need to replace the stanchions, dust excluder nuts, shuttle valves, restrictors, bearings, etc. Pretty much everything is corroded in some way except for the triple trees, damper, lower members and a few other bits. So looking at buying replacement/rebuild parts for these major items I find I am going to spend quite a lot to re-build these. I’m wondering if there is any alternative to this? Like some other fork types that might fit these triple trees or what? Or looking for another fork that I would have to rebuild - but of course it would have to have a lot more good parts. Thanks for any advice.
     
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  5. darkman

    darkman Crème de la Crème

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    There are possibly other after market fork makes out there but i have never bothered as i find the standard spring fork set up perfectly good for normal 60 MPH average road riding on the older Triumphs, Triumph riders in competition/race situations used Cerani forks back in the sixty's and that's all i can offer.
     
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  6. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
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    #186 speedrattle, Jan 29, 2022
    Last edited: Jan 30, 2022
    it can be done. i have a friend who lives near a motorcycle junkyard and is always putting recent japanese forks on his bikes. he does it to get stiffer stanchions and a disc brake. hes done several T120s and at least one A10 that way.

    the issue will be the bearings and the length of tbe steering stem, both of which will usually have to be fussed with.

    one thing you can do without lots of hassles is fit a more recent triumph fork. you can fit a complete 1970s disc brake fork to your 1967 frame, if you locate a lower triple clamp from a disc T150 and use that. tbe steering stem is longer in the tridents. or use an entire trident front end if you are rich. if you dont mind being thought nuts you can use a trident triple clamp on a 1971 or 1972 conical brake front end, which can be made to work very well in spite of the naysayers, and is often cheap. remember the fork widths are different between disc an conical.

    having said all thst, i agree with darkman that the original design is well matched to the performance of tbe machine as a whole, unless youre going to race it. just bringing the original back up to snuff will work pretty well and be lots less trouble
     
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  7. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Forks, well thanks to both of you darkman and speedrattle. The more I look at this the more I will likely just get the parts I need for what I have. I like the idea of perhaps putting on a different front end, but at this stage that would likely be way out of my ability to fuss with all that would take. Forty plus years of corrosion - I suppose it could be worse!
     
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  8. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
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    #188 speedrattle, Jan 30, 2022
    Last edited: Jan 30, 2022
    this id a picture of my 1965 T120 frame with a 1970s TR7 front end. tbe trident triple clamp is the hard part to find. im not using the disc brake.

    [​IMG]

    and this is my crazy friend who puts japanes front ends on triumphs, like this one

    [​IMG]

    ^^^this machine is a major mongrel, but tbats what he does
     
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  9. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Super cool! Why not? Thanks for the encouragement! Love the photo of your bike.
     
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  10. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
    217
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    Arlington, VA
    Taking a closer look at my forks I believe the PO of whoever built the forks last did not assembly them properly. My forks have the shuttle valve H2154, and restrictor. But the restrictor in my forks looks like the restrictor from 1967, part no H1499. From the parts catalog the H1499 looks a lot bigger than the restrictor from the 1969 parts catalog, part no H2090. The older restrictor does not even fit into the shuttle valve. Anyway, just another of the items that reveals this bike was likely put together without a lot of care.

    IMG_2409.jpeg

    IMG_2402.jpeg
     
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  11. darkman

    darkman Crème de la Crème

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    Yes you have the early type fitted, use 2090 and 2091 retaining nut :)
     
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  12. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
    217
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    Arlington, VA
    Fork rebuild question. I am getting parts to rebuild my forks. I am pretty sure these forks are from 1969. The lower member drain plug from these forks are in the first photo. When looking for new drain plugs I see the plug for 1969 as in the second photo (screen capture). I’m just wondering if considering the drain plug type that came out of my forks, could it be they are from a different year than 1969? Thanks.

    IMG_2536.jpeg

    Screen Shot 2022-02-05 at 10.35.15 AM.png
     
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  13. darkman

    darkman Crème de la Crème

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    Early bikes had the long bolt to stop the restrictor spinning, later don't.
     
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  14. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    I’m getting to the point where I need to get some new shocks. As this is a scrambler type of build, I wondering if there might be some recommendations from the forum. I’ve looked at several types: Koni dial a rides, Girling type 13.4”, Hagon premium shocks. The Hagons are more than twice as much as the the others. I’d appreciate any advice on the matter. Thanks!
     
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  15. darkman

    darkman Crème de la Crème

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  16. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
    217
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    Thanks darkman. The shocks on the bike are shot and badly rusted. Do you have any advice on length? That is can one vary this a bit and get a bit more travel than stock? Or does this mess up the handling and geometry? Thanks again.
     
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  17. darkman

    darkman Crème de la Crème

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    If you plan on doing huge jumps then yes you can change springs and get shocks with bump and rebound adjustments but if you just plan to ride on the roads with the odd bit of trail riding then the above shocks are more than upto the job :)
     
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  18. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Got it, probably won't be doing much jumping these days! I'll shop around.
     
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  19. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    How free should the crank run when assembled? So I’ve got my cases together and am wondering how free the crank should be moving? I’ve hear that it is good if when assembled, and the rods are at their lowest point, they should be able to rise themselves due to the weight of the flywheel. Mine don’t at this point. The crank and rods feel smooth and uniform when I run the crank around, however I do need to manipulate it myself by pushing the rods around the crank. I’d appreciate any comments on this in case I need to take it apart again. Thanks!!
     
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  20. darkman

    darkman Crème de la Crème

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    I normally have to assist the rods slightly for them to rise with a freshly built and oiled bottom end.
     
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