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Author Topic: Honda fork flip  (Read 905 times)

Offline redrover

  • Posts: 193
Re: Honda fork flip
« Reply #10 on: Jun 12, 2018, 17:51:11 »
No need -- if you wind up switching the forks just remove the axle and wheel.

Your fender will be reversed and that might look a little odd, if you're running the stock fender.

Ha right. I guess it wouldn’t be too difficult to take off the fork bracket, flip it around and drill some new mounting holes to put the fender back on correctly... Although as slikwilli and irk miller suggested, upgrading to 750 forks might be the ticket.


Offline redrover

  • Posts: 193
Re: Honda fork flip
« Reply #11 on: Jun 12, 2018, 17:55:19 »
I know there are aftermarket progressive springs available for the 750 forks too (and calipers are dual piston), more reason to go that route, but would the heavier (longer) forks noticeably affect handling? Of course would slide them down to the correct height, but how much heavier are they? Also another caliper and disc would increase unsprung weight even more.

Are those aspects worth it rather than just throwing in a stainless steel piston into the original caliper, new MC, SS lines and flipping the fork around?



Offline redrover

  • Posts: 193
Re: Honda fork flip
« Reply #12 on: Jun 12, 2018, 18:01:33 »
I guess it would depend on the bike? Not so much on a 350 or smaller, but possibly on the 450, 500T it 550?

Then again... 550 and 500T come with mounting holes on the right fork leg for a second disc... so instead of 750 forks, could possibly just upgrade to 750 calipers on those originaly forks... Then flip it around hahaa

Still though pondering the idea of a quick easy fork flip... might have to try it.

Offline jpmobius

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Re: Honda fork flip
« Reply #13 on: Jun 12, 2018, 19:53:07 »
There can indeed be a benefit to moving the calipers behind the fork legs, though whether or not you will see it depends on many other factors.  Making this modification on a whim could be a waste of time.  When the caliper(s) are behind the legs, they are closer to the center of rotation of the steering assembly.  This results in the motion of the steering feeling lighter when you lift the front end off the ground and rapidly move the steering back and forth.  You have not reduced the weight, only moved it closer to the pivot.  When you are driving your bike around turns, this has little practical value as the actual motion of the steering is nearly zero.  The benefit comes from potentially increasing the speed at which the steering becomes unstable (speed wobble).  Moving weight closer to the pivot raises the natural frequency of the assembly and in doing so increases the road speed at which this frequency will sync up creating the instability.  If your bike is not unstable at top speed (or on the way there) then you won't see any benefit.  If you have added horsepower and now your bike goes faster and you discover instability, this very likely will help.

There is however, another possible issue due to the basic design of these brakes.  These Honda single piston calipers do not themselves center up on the disc, (as has been noted) their mounting bracket swings on the fork leg to keep the caliper centered.  So instead of being solidly bolted to the fork, they are instead bolted to a mechanism.   Which you will now be loading backwards from how it was designed.  Originally, under braking, the caliper is pulling on its mechanical arm.  Mechanisms like this are generally self aligning.  Loading them backwards is a pretty significant change.  Whether or not this is likely to fail, is dangerous, or even an issue at all I can not say, but it bears considering.  Seems like I have seen it done though.
« Last Edit: Jun 12, 2018, 19:57:27 by jpmobius »
Mobius


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Offline redrover

  • Posts: 193
Re: Honda fork flip
« Reply #14 on: Jun 12, 2018, 22:14:56 »
Wow very insightful info indeed, all makes sense. The backwards spinning wheel on the brake mechanism is interesting/concerning for sure. One way to find out is to try it and keep a close eye on it, I guess?

On the other hand... Do you suppose the benefits of adding an additional caliper/rotor to a 450, 500T or 550 outweigh the drawbacks of having more unsprung weight on the fork?

Or for what it’s worth on these midsize bikes, is it more beneficial to just rebuild the caliper with stainless steel piston, steel lines and new master cylinder?


Offline jpmobius

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Re: Honda fork flip
« Reply #15 on: Jun 13, 2018, 08:48:31 »
Aside from dual discs looking very cool, I think for most bikes you're better off saving the weight.  As you note, it's unsprung weight, and a lot of it.  If you need more brakes, maybe upgrade to a lighter, more powerful late model single disc setup.

Certainly you can rebuild the components.  If you need a new piston(s), you can use stainless steel (if someone makes them or you can machine your own), but the originals are fine as long as the main seal surface is good.  The main thing is to make sure to replace the outer dust seal, as that is the part that keeps out moisture and corrosion.  On average, if the master cylinder does not work, I'd suggest replacing it rather than trying to rebuild it.  If it works and doesn't leak to begin with, it should be like new after replacing the seals.  Braided lines are a good idea, just be sure to not use too large a diameter line.  A -3 line should be right for any bike.  You can also substitute a MC with a smaller bore diameter for more power, but it comes with a trade off of a spongier, longer travel lever, which usually is neither a problem nor objectionable.

I might consider attempting the reversing rotation on the brake mount - I'd have to really examine it first, and certainly keep a close eye on it in use.  However as noted, I would have to have a compelling reason to do it in the first place.
Mobius


On a long enough timeline, the survival rate for everyone drops to zero.

1973 RD350 Yamaha build  http://www.dotheton.com/forum/index.php?topic=66498.0

Offline TheCoffeeGuy

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Re: Honda fork flip
« Reply #16 on: Sep 18, 2018, 12:39:34 »
The people at Honda were not stupid.   Why do you bthink you need that much more stopping power?  Are you racing?  To gain 10 per cent " possibly " more stopping power for the unknown stability issues seems like a no brainer,  if it works, don't fix it.   If it's a look thing, go for safety unless you KNOW  for sure.   I have chopped and customed  a lot of bikes.   Swapping brake direction has never been on my list for looks or performance.

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Offline Sderbyshire

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Re: Honda fork flip
« Reply #17 on: Sep 18, 2018, 18:14:25 »
When upsizing the 33mm forks on my cb360 to 35mm forks i took the opportunity to fit the twin disk setup from a cb550

The braking is significantly better, and i am making a fair comparison as the single caliper was freshly rebuilt and with the same pads i used in the twin setup.

The front end is obviously heavier, but i dont notice a problem, i do have a fork brace fitted which no doubt also helps stability.

Steve

Offline Hurco550

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Re: Honda fork flip
« Reply #18 on: Sep 18, 2018, 18:27:02 »
The people at Honda were not stupid. 

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This argument always gets me a bit. I am not arguing that the guys at Honda were stupid, BUT things have improved since the 70's and so has the way the people at Honda have designed bikes. Also, there was more than just performance dictating how things were designed back then (and now to)... mostly cost of production. That trumps performance most of the time, especially on econo-box-esque bikes like the one in question here.

Not trying to dig you personally, I just hear this being said a lot, and if that were the case 100%, no one would ever need to modify a bike to go faster or handle better... and isn't that what this site is all about?
"If you just picked up a drug habbit instead of a kawasaki triple at least you could get high while you waste money"
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Offline 1fasgsxr

  • Posts: 1498
Re: Honda fork flip
« Reply #19 on: Sep 20, 2018, 13:37:34 »
I know of several guys who flipped them around in the drag racing world to put a little bit of weight farther forward. It didn't cause any issues going over 140mph. Im with you Hurco ! But the irony of the situation?  They went from 2 disc set ups to 1...haha
« Last Edit: Sep 20, 2018, 13:39:49 by 1fasgsxr »
http://www.dotheton.com/forum/index.php?topic=41083.0

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