Street Cup To Street Twin

Discussion in 'Triumph Twin Power' started by Tom Swift, Jan 5, 2023.

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  1. Tom Swift

    Tom Swift Active Member

    Sep 24, 2021
    140
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    USA
    I've been wanting to replace my heavy Yamaha with the Street Cup for carrying a passenger. I just got a Street Twin seat that was an easy swap but ran into trouble with the grab rail that's needed to mount the sissy bar. One side of the rear brace was welded on crooked so it had about an eighth inch of interference with the frame. Not only that but the hoop in back didn't clear the taillight.

    I didn't want to send it back since it was a $76 ebay part and I wasn't about to cut and reweld it. I figured I'd try to bend it to fit. Many hours later, it fit pretty well but the bends I had make were so severe that much of the powder coat flaked off.

    I just ordered the sissy bar and rack combo from Amazon.
     
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  2. Geoff Butler

    Geoff Butler Never too old for Biking!
    Subscriber

    Apr 5, 2021
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    Hampshire & Powys
    Hi Tom,

    I had a similar issue putting a grab rail on my Street Cup when I first got it in 2017 and had to put a standard Street Twin seat on instead. It sounds like your sissy bar is fouling in the same way where the seat does not lock down and I guess the best but most expensive solution would be to use genuine Triumph parts so goo luck with your Amazon purchase. :)

    Cheers

    Geoff
     
  3. Tom Swift

    Tom Swift Active Member

    Sep 24, 2021
    140
    43
    USA
    #3 Tom Swift, Jan 6, 2023
    Last edited: Jan 7, 2023
    There's no problem fitting either seat once the mount was straightened and loop bent upwards. I think the tail light on the Street Cup sits up higher than the Street Twin so it still would've had that problem even if the grab rail mount wasn't crooked or I had ordered the OEM grab rail.

    The sissy bar part will be much easier to tweak if it needs to be. The hard part is done and I'm glad it cost less than the OEM grab rail which most likely would've needed the loop bent up to clear tail light also. I used a hydraulic press to get it about a half inch higher so it clears the tail light by about an eighth inch without the use of spacers which would've made it impossible to install the seat without shiming up the latch.

    After I get the sissy bar mounted, Ill pull the grab rail back off and paint it wherever the powder coat flaked off. Those areas are mostly hidden.

    [​IMG]

    EDIT: I looked at the parts diagrams and it seems like the taillight heights are the same for the Street Twin and Street Cup.
     
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  4. Tom Swift

    Tom Swift Active Member

    Sep 24, 2021
    140
    43
    USA
    The only OEM grab rail made for mounting a sissy bar is for the T100 which must have a lower tail light because the upward bend at the loop looks about the same as the aftermarket. OEM part# A9758329 would still need to be bent to clear the Street Twin/Cup tail light.
    [​IMG]
     
  5. Tom Swift

    Tom Swift Active Member

    Sep 24, 2021
    140
    43
    USA
    The Street Twin seat had too much of a slope forward for both rider and passenger so I reshaped the foam to sit both flatter. Both rear sections were shaved down to about a quarter inch from the plastic base and rider seat now lets me sit about a inch further back. By comparison, the Street Cup seat seemed more roomy and less tilted forward.
    seatcarved.jpg
    Looks like the ETA for the backrest is at least two weeks away.
     
  6. Tom Swift

    Tom Swift Active Member

    Sep 24, 2021
    140
    43
    USA
    I saw an old thread mentioning jack-be-quick risers that raise the handlebars another 19mm and decided to make my own out of some extra Delrin I had.
    [​IMG]
     
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  7. Tom Swift

    Tom Swift Active Member

    Sep 24, 2021
    140
    43
    USA
  8. Tom Swift

    Tom Swift Active Member

    Sep 24, 2021
    140
    43
    USA
    The backrest and rack finally arrived. Had to drill a couple new holes in the uprights because the factory holes made the backrest angled straight up. Decided not to install the rack for now.

    [​IMG]
     
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  9. Tom Swift

    Tom Swift Active Member

    Sep 24, 2021
    140
    43
    USA
    [​IMG]
     
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