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Thread: 916, etc throttle bodies on 851?

  1. #31
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    Jun 2007
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    i'm way too lazy to replace the closing springs on an engine in the chassis. i don't need that sort of agro. and too lazy to pull the heads. so it'll stay as it is i expect.
    Brad The Bike Boy

    www.bikeboy.org

  2. #32
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    france
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    I understand you haven't only one to look after! In my case , only one.
    i spent so many hours of settings, disassemblies, mappings, trials etc...that when i discovered it was the main cause of this crappy running at low revs, i throw myself on the heads and these poor springs.
    I operated on the bike, it's not easy but faisable.
    So you have to drive it like a Superbike, in fact its first target, from 5000 rev😊
    Mine now is so nervous and happy to hight rev with the heavy springs and overall the cam timing, that I decreased the red zones (fuel and ignition cuts) at 9500 revs to secure the crankshaft.

  3. #33
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    i'm sure we spoke about this years ago. i was a little concerned as to the reliability of the 1.5mm collets and the heavier springs. but really, laziness is the bigger issue.

    i did make a tool a while ago for flipping the spring tails in with heads on engines. funny, some days it works with no effort, some days it's still a nightmare

    i rode it the other day with all its low speed crankiness. i'm sure it's going to shit me endlessly until i do actually fix it.
    Brad The Bike Boy

    www.bikeboy.org

  4. #34
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    france
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    Yes Brad we spent a lot of discussions on this 90 bike!
    I was confident with the stronger valve springs and small rings couple, because my friend 91 one had it (i saw the springs on it for sure, and the valves are the sames in 91)
    For information, after a few thousand of kms including a few harder uses, on track demonstrations (the reason why i set the cuts at 9500 &#128567, i recently checked and set the valves plays, the 1.5 rings haven't (yet...?) shown worrisome traces of crushing or wears.
    Hoping again a long life to it ,and yours; now 67000 kms, no signs of weakness.
    Pat

  5. #35
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    old vs new.
    Attached Images
    Brad The Bike Boy

    www.bikeboy.org

  6. #36
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    On stripping down quite a few early heads with the 1.5mm half rings, I've found several of them broken.
    But I've never found any of the later 1.75mm half rings broken, although they do crush down.
    I now use MBP Collets and have never had one break or crush down.

    Steve R

  7. #37
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    computer says i've bought 215 1.7mm collets in 10 years, a few replacing lost ones.

    i see quite a few broken 1.7mm, esp on things that get revved.

    i found 91 models had heavy springs and 1.5mm collets, so that put my mind at ease a little. altho they also had the 009b eprom, which makes me wonder how they ran at low speed.
    Brad The Bike Boy

    www.bikeboy.org

  8. #38
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    i did a piece for my blog about the spring change, as i hadn't done anything there for months. i'm too lazy to replicate it anywhere else due to having to put the images in everywhere.

    https://bradthebikeboy.blogspot.com/...ge-on-851.html
    Brad The Bike Boy

    www.bikeboy.org

  9. #39
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    Quote Originally Posted by brad black View Post
    i did a piece for my blog about the spring change, as i hadn't done anything there for months. i'm too lazy to replicate it anywhere else due to having to put the images in everywhere.

    https://bradthebikeboy.blogspot.com/...ge-on-851.html
    You'd be the one to know! ST4 engine in late 888 strada, what airbox will work? 888?

  10. #40
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    everything should just be normal 888.
    Brad The Bike Boy

    www.bikeboy.org

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