Honda fork flip

jammer415

Been Around the Block
So Honda forks in the 70’s for some reason had the calipers leading in front of the fork legs, but virtually every other motorcycle has the calipers located behind the fork legs.

I was doing some research about this and it seems that if the caliper is located behind the fork leg, this may improve handling.

Why not just slide the forks out from the trees of any of our 70’s Honda bikes, and swap them around so the caliper is now located behind the fork leg?

Does anyone know if this would help with handling while braking? Or is this a stupid idea?
 
Honda's calipers at that time weren't floating. The bracket that they mounted on floated, and the casting of the lower only allow them to be mounted one way. Plus the castings for the fender mounts are an issue too. You could upgrade to a floating double pot caliper and flip the location with a custom bracket, but you can't reverse the location of the stock setup.

frontbrakecloseup.jpg


I guess, maybe you're suggest running the caliper on the right side. That's a different story. You could run them on that side, but all of your braking would be on the right side, which I imagine would make it pull right. Another option for some bikes is to run CB750 forks, which are on the back side.
 
Yup, that’s what I meant... To swap the fork legs around, with the wheel attached, so the caliper is still mounted the same, only now located behind the fork (instead of in front), but on the right side.

Also, if the bike doesn’t pull left when the caliper is on the left (original side), why would it now pull right when the caliper switched to the right?
 
redrover said:
Yup, that’s what I meant... To swap the fork legs around, with the wheel attached, so the caliper is still mounted the same, only now located behind the fork (instead of in front), but on the right side.

Also, if the bike doesn’t pull left when the caliper is on the left (original side), why would it now pull right when the caliper switched to the right?
Your rotors are on opposite sides of the bike in the stock position front to back. I don't know that that's true, just speculating the possibility. Seems like an GS500 or something has the rotor on the right side.
 
I’m referring to all Honda CB/CL from the early/mid 70’s... They all came with a single disc rotor on the left side of the wheel with a caliper mounted to the left fork leg.

I’m just pondering the idea of sliding out the fork legs from the triples and turning them around, so the left fork leg goes into the right triple hole (and vice versa)... The result would be a caliper mounted behind the fork leg (like all modern bikes), only being on the right side.

I guess the only thing remaining would be to flip the tire around on the rim, since it would now be spinning backwards (and some tires are directional).
 
I've seen it done on several builds I've read though, on other forums.

Maybe even one on this forum, can't remember.

Haven't done it myself, but considered it a while back, still may.

I do remember telling someone, they had their forks on backwards, but they wanted them that way.

One thing though, the drain screws would be to the front so it would be harder to drain the fork oil, come changing time.
 
redrover said:
I guess the only thing remaining would be to flip the tire around on the rim, since it would now be spinning backwards (and some tires are directional).
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.
 
I ran my calipers on the rear a while back when I had stock dual discs. Its and easy enough thing to do, but how much difference it makes is probably immeasurable to the average rider. You would be far better off in the handling department to go bigger on forks and get a caliper that doesn't suck so much.
 
slikwilli420 said:
You would be far better off in the handling department to go bigger on forks and get a caliper that doesn't suck so much.
This is why I suggested the CB750 forks. Easy, straight up swap and helps handling. Not modern, obviously, but an improvement over the twigs the early twins came with.
 
carnivorous chicken said:
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.
 
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?
 
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.
 
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.
 
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?
 
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.
 
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.

Sent from my SM-T813 using DO THE TON mobile app
 
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
 
TheCoffeeGuy said:
The people at Honda were not stupid.

Sent from my SM-T813 using DO THE TON mobile app

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?
 
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
 
Back
Top Bottom