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Thread: Gently used front SC2 for sale

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    AMA Superbike Champ *GT*'s Avatar
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    Gently used front SC2 for sale

    Only good for left turns. LOL! Apparently the Daytona is a little sensitive to geometry changes. I changed the gearing and subsequently shortened the wheelbase. I ended being 3-4 seconds off my previous pace at Putnam. Made for a miserable and humbling day. The learning curve has been steep! Back to the drawing board.


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    Jeff

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    World SBK Champ Dave608's Avatar
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    That's extreme. How big a gearing change did you do? Granted shortening the wheelbase will impact geometry but shouldn't have that negative an impact.

    What tire pressure where you running? And more importantly do you know if your gauge is accurate? That looks like wildly wrong air pressure to me.
    Dave
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    Motorcycling is not, of itself, inherently dangerous. It is, however, extremely unforgiving of inattention, ignorance, incompetence, or stupidity

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    AMA Superbike Champ *GT*'s Avatar
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    Quote Originally Posted by Dave608 View Post
    That's extreme. How big a gearing change did you do? Granted shortening the wheelbase will impact geometry but shouldn't have that negative an impact.

    What tire pressure where you running? And more importantly do you know if your gauge is accurate? That looks like wildly wrong air pressure to me.
    Went from 15/44 to 15/47, which is the stock config, to get more drive out of the corners. I also wanted to play around with shortening the wheelbase. I ran the front hot at 33psi. I use a Motion Pro digital gauge. I've literally used it three times now so I doubt it's out of calibration. Possible but doubtful. I'll have it tested next time just to be sure.
    I had two previous track days on the tire and it was wearing perfectly up until I changed the gearing/wheelbase. You can never cancel out human error. I may have goofed it up but I was religious about checking pressures. The tire was also plowing a lot more than usual after the geometry change.


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    World SBK Champ Dave608's Avatar
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    Yeah, the gauge may be fine but worth testing, I've got the same gauge and was only .1 off a Dill calibration device. The new surface is ridiculously abrasive, I ran the SC2 last time as well but I run 35 hot. 2 psi wouldn't be enough to do that though although I had some very minor tearing. A 3 tooth change isn't ridiculous, I do that regularly on my 750 without such dire changes. Maybe your setup was closer to the ragged edge to start with though and that just pushed the trail numbers on the front over the edge. Try either raising the front a couple of mm or taking 1/2 to 1 turn out of the shock ride height (if you have a shock you can adjust, if not just raise the front).
    Dave
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    AMA Superbike Champ *GT*'s Avatar
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    Quote Originally Posted by Dave608 View Post
    Yeah, the gauge may be fine but worth testing, I've got the same gauge and was only .1 off a Dill calibration device. The new surface is ridiculously abrasive, I ran the SC2 last time as well but I run 35 hot. 2 psi wouldn't be enough to do that though although I had some very minor tearing. A 3 tooth change isn't ridiculous, I do that regularly on my 750 without such dire changes. Maybe your setup was closer to the ragged edge to start with though and that just pushed the trail numbers on the front over the edge. Try either raising the front a couple of mm or taking 1/2 to 1 turn out of the shock ride height (if you have a shock you can adjust, if not just raise the front).
    I think you nailed it on the head regarding setup. The Daytona has a ridiculously steep trail angle out of the box. I had KTech carts dropped in just before the season kicked off and I'm thinking the spring is too heavy (1.0) and the forks are sitting a 3-5 mm too high in my triples. I read that Dave Moss recommends dropping them flush with the triple clamp, or upgrading to an adjustable yoke. My JRi is ride height adjustable but I think I'm going to try the front first unless you think I'd gain more from dropping the rear.

    Now that I've discovered she's sensitive to minor geometry changes I'm going to have Eric with Velocity run it through his geometry testing device. I can't afford to keep shagging tires at this rate! It was amazing how much confidence I lost just from a minor wheelbase change.

    Thanks for chiming in Dave. You helped confirm the direction I was planning to go.


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    World SBK Champ Dave608's Avatar
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    On the spring weight, don't get hung up on a spring rate chart, those are only a general guideline as a starting point, riding style impacts that far more. Someone who is aggressive on the brakes, etc will often need a heavier spring.

    On the fork height the measurement might be your best bet. I always hate general advice like "flush the front forks", you have to have a reference for that as well like when the forks are stock. Some cartridge kits can internally extend the fork length for example and then you are too high in the front. It's for that reason I prefer to use a more accurate reference like xxx mm from the top of the lower triple to the centerline of the axle.
    Dave
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    Motorcycling is not, of itself, inherently dangerous. It is, however, extremely unforgiving of inattention, ignorance, incompetence, or stupidity

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    Quote Originally Posted by Dave608 View Post
    On the spring weight, don't get hung up on a spring rate chart, those are only a general guideline as a starting point, riding style impacts that far more. Someone who is aggressive on the brakes, etc will often need a heavier spring.

    On the fork height the measurement might be your best bet. I always hate general advice like "flush the front forks", you have to have a reference for that as well like when the forks are stock. Some cartridge kits can internally extend the fork length for example and then you are too high in the front. It's for that reason I prefer to use a more accurate reference like xxx mm from the top of the lower triple to the centerline of the axle.
    Thanks for the advice. I'll measure it out from the axle to lower triple rather than throw shit against the wall. Do you use a basic tape measure or something more gnats ass?

    As for the fork springs Eric recommended going with a lighter spring based on his past experience with KTech and his MotoA riders. It seems to jive with what other Daytona riders are saying as well.


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    World SBK Champ Dave608's Avatar
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    Tape measure is fine, I use a metric one but either will work. Once you are in the ballpark then you can use the exposed fork tube method and measure more finely for future adjustments, it's having a solid starting point that's important.

    On spring rate, as long as you are working with someone who has some real world data, that's the important part. If his experience says lighter that may well be the way to go.
    Dave
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    Quote Originally Posted by Dave608 View Post
    Tape measure is fine, I use a metric one but either will work. Once you are in the ballpark then you can use the exposed fork tube method and measure more finely for future adjustments, it's having a solid starting point that's important.

    On spring rate, as long as you are working with someone who has some real world data, that's the important part. If his experience says lighter that may well be the way to go.
    If u want it right, take it to the Englishman in Corydon.

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    Quote Originally Posted by *GT* View Post
    Only good for left turns. LOL! Apparently the Daytona is a little sensitive to geometry changes. I changed the gearing and subsequently shortened the wheelbase. I ended being 3-4 seconds off my previous pace at Putnam. Made for a miserable and humbling day. The learning curve has been steep! Back to the drawing board.


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