Might order a TB stroker kit and big bore, anything else needed?

Discussion in 'Tech Area' started by hrc200x, Dec 1, 2019.

  1. hrc200x

    hrc200x Active Member

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    Thinking of taking advantage of TB sale and ordering a big bore kit, stroker crank, and high volume oil pump. I don't see a kit that offers all those parts in one so am piecing together. Don't have a bike in mind yet for the parts but it would probably be a auto K0-81 ct70.

    Would this be the crank I'd need for a 3 speed auto? https://www.tbparts.com/product/tb-stroker-crankshaft-51mm-6v-various-3-speed-models/

    or there is this one:
    https://www.tbparts.com/product/tb-stroker-crankshaft-51mm-6v-various-3-4-speed-models/

    With one of those stroker cranks and this bore kit make it what cc? https://www.tbparts.com/product/tb-race-head-88cc-bore-20mm-carb-kit-k0-81-models/

    any thing else need to order other than this oil pump?

    https://www.tbparts.com/product/tb-high-volume-oil-pump-k0-81-models/
     
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  3. kirrbby

    kirrbby Well-Known Member

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  4. kirrbby

    kirrbby Well-Known Member

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    That BB kit, plus the first crank that you posted would give you 108cc. The 2nd crank you posted is the 4speed type.
    Check out tbolts kits tho. Might be more better.
     
  5. lukelaw1

    lukelaw1 Active Member

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    I have built 2 strokers and personally I wouldn't piece together. Buy a kit with the V2 race head but without the vm26 Mikuni carb, I used the vm20 on both and they rip. With all that potential power you don't want to be restricted by the head. The ct70 is just stupid scary without an extended swing arm, hard to keep front wheel down, and the cl70 is better balanced and goes!! I built both motor from scratch.

    I'd also get a temp gauge dipstick and hd clutch pack.
     
  6. hrc200x

    hrc200x Active Member

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    Thanks for the suggestions, am waiting to hear back from TB and see if they can put together a complete kit of what I need.
     
  7. racerx

    racerx Administrator
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    The V2 head is only going to deliver the goods at high rpm, thus I'd go for the equivalent of the Takegawa s20 cam, plus a TB billet clutch basket. I don't know if the s25 & s30 grinds are available any longer; they made high-rpm horsepower but didn't last long. The weakest link in this chain, imho, is the roller rockers.

    In terms of usable power, even a fairly basic 52x51 tune, wearing a 6v CT70 head, fitted with one of the two perfomance cam profiles the `doc sells, should deliver 60mph power, with the same, or slightly more low-end grunt. FYI, the TB head is basically a 12v CT70 head, with the bigger 6v-era ports.

    Either way, you'll get a huge increase in road-friendly power, should be good for low-to-mid 50s...sustained cruising + crisp acceleration...to go along with that low-60s top speed.

    How do you feel about 6v/breaker point electrics vs 12v/CDI? Your answer to that question may make stepping up to a 54mm crank worth considering. I'll stop my ramblings here...before causing a migraine.;)
     
  8. dirtbkr188

    dirtbkr188 Active Member

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    The only thing I'd be concerned with is the correct piston for the stroker crank. The piston in the big bore kit is for a short-rod engine and probably won't work with the long-rod stroker crank
     

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