Eproms And Exhausts

Discussion in 'Sport Touring' started by Jim Harrison, Mar 21, 2026.

  1. Hi,

    I have had my ST 2 for a couple of years and love it. But I’m finding it runs very rough below 3000 rpm and sometimes seems to cut out then back in suddenly when engine below 3000 rpm when hot, resulting in a loud jolt and clunk from the transmission.

    When I got it, it came with a spare EPROM 08054/9 which I gather is for performance exhausts? Currently I have the standard EPROM installed. How can I check if it has the performance exhausts or standard? Just want to rule out having the wrong EPROM installed

    thanks

    Jim
     
  2. Is it noisy. Would be a clue. Post some pics of them, any ref numbers stamped into them and of the outlets.
     
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  3. A few photos, they are not particularly noisy so I’m guessing they are standard not performance? IMG_5235.jpeg IMG_5236.jpeg IMG_5237.jpeg
     
  4. Standard type-approved and baffled exhausts
     
    #4 chrisw, Mar 22, 2026
    Last edited: Mar 22, 2026
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  5. Great thanks, I’ll stick with the standard eprom and look elsewhere for the carse of the rough running at low rpm. Much appreciated
     
  6. On the intermittent cutting out, I'm wondering if there is not a dodgy electrical connection or component playing up.
     
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  7. If this occurs when hot, start with the TPS. Resetting it requires a multi-meter and you can find plenty of stuff on the net on how to set a non-linear TPS.
     
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  8. This might be a better strategy
    1. Check the crank position sensor CPS
    2. Swap coils or test them
    3. Check for vacuum leaks
    4. Set the TPS
    5. Fuelling - fuel filter, then injectors
     
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  9. Hi Jim,
    Glad you are enjoying your ST2, I've only been enjoying mine for a month now but it's really fabulous to ride. I too found that it can be a handful below 3000rpm and many suggestions were offered by this great bunch of enthusiasts about possibly changing the front sprocket to 14 tooth. Have a look at the thread titled "Thoughts and Feedback please"

    Happy riding:grinning:
     
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