Suspension Upgrades

[EMS]

Almost all contemporary test reports for the new Prolink model show a rake of 29.5° in their technical specification listings.

Motorcyclist in the 8/81 issue road test even goes into detail:

The Pro-Link mechanism requires more space between the engine and rear wheel, which has stretched the wheelbase out to 60.4 inches. With the new fork came new, wider triple clamps, which keep the trail at 4.7 inches, even though the steering-head angle has been notched back two degrees to 29.5° degrees.

Cycle magazine in April of 1981 had said the same before;

One thing Honda did was to revise the CBX's steering geometry and its fork very extensively. They re-angled the frame's steering head to provide 29.5° of rake, two more than before, and then made up fork bridges with more forward offset to hold the trail at 120mm (4.72 inches)

As the magazines usually do not do their own measurements, one can only assume that they received that information from Honda.
If that is the case, it is quite possible, that Honda had intended to make these changes, but in fact did not execute them when the bike came into production.
Later test reports for the 1982 model then show a 27.5° angle.
Considering that the first shop manuals were printed before the bikes were available, it would be interesting to find an early 1981 Honda shop manual and see what the specification listed in there is.
Later edition Honda official shop manual ( '81~'82) shows a rake angle of 27.5° (or caster of 62.5°).

[Syscrush]

It's a very interesting bit of history.

Every now and then a story breaks about a manufacturer publishing BS about one or another of their bike's specs, and I've always wanted to see a feature that goes in depth in measuring stuff & reporting on the biggest & most frequent lies.

[Syscrush]

Top triple with KTM Duke handlebar risers/clamp in place. Machinist insisted on making that nice smooth replacement (or maybe just cover) for the stock nut. This shape keeps me from having the forks protruding so far above the top of the triple, and will also place the bars a bit higher for some additional comfort.



I am very pleased with how the custom triple works with the stock gauges.



Here comes the mea culpa... I know that some of you are gonna be pissed that I let him chop up an original top triple. I don't feel very good about it - when he called and said that he wanted to do it, I was pretty upset. But the end result looks like a pretty cool solution to retain the original instrument cluster and headlights.



Nice beefy bottom triple.



I told him that I didn't want to see the bolts from the front, and he did a great job of keeping it nice and clean.



Kept the stock fork spacing so that I could use that sessy SuperBrace. I'll be kinda nervous until I see all the upgraded brake stuff actually fit with the wheel assembly, but he`s confident it`ll work - and these results make me inclined to believe him.

[daves79x]

I wouldn't beat yourself up over the stock triple clamp - they're not quite a dime a dozen, but plentiful. Looking good! I wonder if you really need a fork brace now?

Dave

[EMS]

That's really cool. Now, Phil, how exactly did he incorporate the instrument holders into the new top clamp?

[daves79x]

Looks like to me he just chopped off each end of the stock triple clamp and slid them (with the gauge ears still intact) down on the fork tube under the new triple. Neat way to use the factory parts to mount the gauges.

Dave

[Syscrush]

Looks like to me he just chopped off each end of the stock triple clamp and slid them (with the gauge ears still intact) down on the fork tube under the new triple. Neat way to use the factory parts to mount the gauges.

I believe that's exactly what he did. I haven't seen it in person yet.

To be honest, I have serious doubts about the value of a fork brace on just about any bike - it's hard for me to imagine that forces that can deform the forks wouldn't also deform the brace, but I figure it's something cheap & easy to do, so why not? I'm not crazy about adding the unsprung weight, but the switch to proper cartridge damping should make that a lot less problematic.

The 2 remaining concerns are:

1) Can the 4-piston calipers be made to fit with enough clearance to ensure safe operation?
2) Will it be possible to retain the stock speedo drive, or will the new adapters/rotors interfere with it too much?

[EMS]

O.K., I missed that the fork tubes are still stock CBX size. I thought it was a different front end.

[Syscrush]

O.K., I missed that the fork tubes are still stock CBX size. I thought it was a different front end.

Pro Link 39mm forks with all-new AK20 cartridge internals, Sonic Springs and new TNK tubes. So bigger than the stock '79 forks, but the '79 gauges fit to the Pro Link top triple.

[Syscrush]

It would appear that I needn't have worried that the oversized rotors would obscure my much-beloved boomies:


I intentionally chose rotors with that lacey carrier design so I could see the wheels through 'em. I'm very happy with how this is turning out. I think that with the adapters painted to match the wheels, this setup will look really right.

One issue that I hadn't anticipated before dropping the brake parts off with the builder is that it really wasn't doable to fit the OEM speedo drive. I hate like hell to give up the OEM gauges, but I think I have a good plan for replacements that won't look too out of place.

[steve murdoch icoa #5322]

Phil, give it another try on the front wheel photo.

[80 cbx dude #6216]

Looks Sweet!! Very nice!!-Mike

[Syscrush]

Phil, give it another try on the front wheel photo.

Fixed!

[johnod]

NICE

[Syscrush]

NICE

Thanks, I'm very happy with how it's looking so far.

Can someone confirm for me that the gold boomerang wheels are anodized, not painted? I want to get those adapters done to match.