Prolink Fork In Early Model Frame & Steering Damper

[cbxtacy]

for some reason tires play a part also. I've noticed on my stock prolinks a wobble at (around) 55 when I take my hands off the bars. Much more prevalent with worn front tires. When I put a new front tire on it, the wobble goes away until the tire gets worn. Just put a new Dunlop 501 on the front. I have spare rims and I'm mounting a set of Kenda's for any trips I do to South Dakota this fall.

[alimey4u2]

Wondering if Larry noticed any improvement when he went with the new Dymag wheel? Did things improve even more when you stiffened the front end by going to the 39mm ProLink forks? Riding impressions (without the dampener) at each stage of modification would be interesting . . . . and if you felt the dampener was still needed after all was said and done - Evidently you did as I gather the first time you installed the dampener was after all of the other improvements failed to solve the problem . . . . true?

Progress has been over decades I'm afraid, I noticed a quickening of steering having gone to 18 " front & rear Dymags ( the only size they made.) I initially wasn't impressed, as I got a falling in sensation going into bends. I came to realise that was due to a 160 rear tire matched with a 110 front. I dropped the rear to 150 & started to enjoy myself. Now, I also upgraded to Performance machine brakes & discs but found that the skinny forks seriously complained under maximum braking. The juddering fork caused a skipping contact patch which is not good. This being one of the reasons I went with 39mm forks this year. The damper modification was installed from those early memories of tankslappers. Any bike under those circumstances would have shook its head also.

Dymags.
I like a lot but are very sensitive to incorrect sizing & worn rubber. Ideal for for me being 110/90-18 up front & 150/70-18 rear. Any other tire combination & you will not see any real improvement. Go too radical on the rear & it will be worse.

39mm Forks.
Wish I had done it years ago, I really get a nice feedback what the front rubber is doing. Now feels "planted".

Steering damper.
Well I hope I don't get in a situation where I really need it. However, early days yet, just put it on & then buried by family commitments. Watch this space...

OK, I'm now older, wiser & riding on heavily congested diesel oil contaminated roads. I'm no longer pushing the envelope, I just want to ride safely & be smooth... However, I was followed by a young man on a fairly modern sports bike, the other day. When we arrived at our destination the young man said: " You can ride !!!" Blushing, I said I had been doing it for 42 years so I hope I have the hang of it now...
Is the bike better ? Well I rode a stock bike a year or two ago & it was a different animal all together.. I love my CBX now...

Other frame related mods:

Calfab swinging arm unit complete with underbrace & eccentric adjusters. ( this slightly shortens the wheelbase.)

Koni rear shocks

My findings are based on my weight/ height & style of riding. This may not be a "fit all" formula for everyone. Others may differ.....

[EMS]

My wire wheeled 79 isn't real stable with or without it. It got a steering damper from when I road raced it and they were mandatory. My 82 needs one. My turbo (82 with VFR single sided swingarm, CBR600F3 front wheel) doesn't need one. Same suspension geometry but half the unsprung weight.

Same suspension geometry How the hell did you do that? Smaller front wheel, different swingarm???
Steering neck bearing misalignment is also a common cause for front end wobble. I find it very surprising that any of you experience a Prolink to be less stable around the front end than a stock '79/80.
Rake and trail, front and rear wheel alignment contribute to unstable front ends.

[cbxtacy]

What I meant was on my 82 turbo I didn't change the fork clamps. Rear ride height is the same and I used longer front forks to get the same rake and ride height in the front. The trail is less because of the smaller dia front wheel. It never wobbled at around 55 like my other pro links with stock wheels. So the big difference is wheel/brake mass and weight and trail. I believe the biggest contributing factor to stability is weight. Could be rong.

[Mike Barone #123]

...Another point is the CBX is no Moto GP bike that responds to micro suspension adjustments in my view. Along these lines......we had an expert suspension setup person attend one of our rallies long ago and measure the chassis setups of eight or so CBXs .....and the one most out of "specs by the book" and alignment just happened to be the best handler...

Mike

I know it was long ago, but maybe you could remember enough about what the good handlers had different about them to share it? :)

Sorry I missed this...........actually of the 8 CBXs that were tested for setup by the chassis/setup expert at that rally.........only one was not within specs.......it just happened to be the best handler of the lot. This is a few of the areas deemed not acceptable.

1. Sag incorrect and far out of any proven "high theory" acceptable ranges in all the setup articles

2. 1100f rear swing arm axle hole enlongated forward with round file so original CBX chain was long enough to fit and also keep or shorten wheelbase a bit.........problem was .........the drunk that did the filing had the two sides off by 5/16ths of an inch so back wheel was out of alignment by this much

3. Right and left side 1100f rear shocks had different settings


The suspension expert and his VFR800 were unable to confirm the CBX with the bad setups handling on the twisties sport ride .....he was too far behind.

Again........I realize all the stuff magazine editors write is correct and stuff they use on MotoGP bikes applies to everything including mopeds.......but sometimes actual real world experience that is documented............ does count for something.



Unique out of the way steering damper placement for a CBX or any bike

[alimey4u2]

Great thread with some superb input from all.....

Just as a continuance & as a "thank you" to all whom have subscribed to this tread. I'm going to share my latest invention ( ) an inexpensive, super accurate, one man to operate, wheel alignment tool for you all. Off to the shed tomorrow, have the components in hand, so watch this space.....

[EMS]

The trail is less because of the smaller dia front wheel. It never wobbled at around 55 like my other pro links with stock wheels. So the big difference is wheel/brake mass and weight and trail. .

Does not make sense. Less trail is usually more prone to wobble. Think of the shopping cart example! Also, smaller front wheels do create a "sudden tipping" steering behavior, which is being perceived as unstable.
I must be the only one in the world who had a bad experience putting a Prolink fork into an early frame.. .. and who has a Prolink that is more stable at high speeds straight than my '79 with a stock front end.

[cbxtacy]

I've never put a prolink fork in an early frame. All my prolinks have been stable at high speeds but with worn rubber they have a head shake at 55 mph. They're still stable above and below that. And you won't notice unless you let go of the bars at 55. My 79 has '80 GS1000 fork tubes (37mm) and the CBX fork clamps were machined out to fit. The wheel is a GS750 with a 2.5x18 rim laced up. It doesn't get a head shake at 55 but it doesn't feel as stable at high speeds as the prolinks.

I believe there's a flaw in the suspension geometry of the CBX because there's too many I've had and others I've seen that arn't real stable. But that doesn't mean you can't go fast on them, it just means they don't feel real stable when leaned over. Like a lot of big, heavy, wide bikes with skinny forks, swingarms, wheels and tires from that era. If you're from that era and you rode and remember the beasts from then, the CBX is a nice ride.

If you're from the more modern era with 400 pound motorcycles with 175hp, rigid chassis, big brakes, and fat/sticky tires, then the CBX might have a tendency to scare the c**p out of you if you push it. The only way I can cure my CBX addiction is if someone comes out with something that sounds and looks better then the CBX.

[EMS]

I still remember my '79 when new and I did not feel anything bad that indicated a design flaw in the suspension. Actually, it was a vast improvement over bikes like the Kawasaki Triple, the Honda CB750SOHC or others that I had before. There is no doubt that one can improve the handling of the CBX because measured at today's standards, sure, it may be poor, but then again, if I want to flick a bike through the corners, I hop on the Ducati.

[alimey4u2]

Great thread with some superb input from all.....

Just as a continuance & as a "thank you" to all whom have subscribed to this tread. I'm going to share my latest invention ( ) an inexpensive, super accurate, one man to operate, wheel alignment tool for you all. Off to the shed tomorrow, have the components in hand, so watch this space.....

viewtopic.php?p=26485#26485

[alimey4u2]

Any tips/tools on getting the top nuts on a Prolink fork.... I am installing Hagon springs & it's a devil ( I'm being nice too) getting the nuts on with all that preload. Hagon say don't use the spacers... Thank the Lord I don't have to fit them too.... Been at it all morning & before I F*** the threads, thought I would ask...

[EMS]

Other than what you probably already do - extending the forks fully, best be done out of the bike - I have no advice. It can be tricky, depending on the springs you use

[alimey4u2]

Thanks Mike, That's what I thought.....

Looking at the diagram, dropping the bottom socket bolts achieves nothing.. Or am I wrong ?

[EMS]

The assembly procedure says to put the spring in BEFORE you thread in the socket bolt. Maybe it will give you a few more mm free space???

....then again, in the following steps it goes through filling the fork with oil and taking the caps off again. Maybe it doesn't matter.

[alimey4u2]

These Hagon springs have a bunch of preload, I'm talking about 2 inches of compression before I get near the thread area. I have a plan which doesn't entail disassembling the forks ( again.. ) & will make the job easier in the future. Off to the hardware store tomorrow...