Topic: Pros/Cons 550F Fork Rebuild/Replace Advice?

[RodPlunger]

Hi all,
So, my front forks on my '77 CB550F are leaking and are in need of some repair. And at this point, I am considering all my options for making the bike handle as best as I can. It seems to me I have about 3 options:

1: Replace seals on OEM forks, change the oil and put it back together as factory....
2: Install emulators, change to constant rate springs and put it back together...
or 3: Find a modern front end that I can replace the entire fork setup with.

Now, a couple of things. Should I plan/want to change out the head bearings with AllBalls tapered while I have the whole thing apart if I am sticking with stock forks? I plan on using clip ons to replace the handlebars on the top of the tree. And, what do most people do about the top plate of the tree to eliminate the mounts for the handlebars?

I understand from reading through the forum, that tuning the front forks with emulators is a bit of an art form. Also, that it involves welding. Of which I don't have the gear, and haven't welded in years... Is this a good route? It seems financially moderate and looks to provide great results. I just don't want to spend the next month trying to get the front end operating properly, and don't need to do something that only provides nominal improvement...

Now, for changing out the front end entirely. Is there a "standard" fork I should be looking for? I have seen people use GSXR fronts but what years? Also, It seems like the steering stem in modern units is straight, while our late 70's models are tapered. Is this something difficult to overcome? AllBalls bearings again? And lastly, is it worth the conversion? Having the opportunity for dual brakes up front sounds great, but if I have to custom fab just about everything to get there, maybe its return is not worth the investment.

Thanks for any and all feedback/advice. Feel free to explain it to me like I am a 12 year old. I sometimes find in all forums like ours here, that things can get missed in both the misunderstood shorthand parlance and general virtuosity of knowledge from some of the more experienced members in translation to the fairly green wrenchers such as myself...   In other words, don't feel bad about explaining it to me like I am an idiot. Thanks again...

[brooze72]

Well I can only offer an opinion so here goes;

If the fork tubes are in good shape, it is worth a rebuild....but it would depend on what kind of rider you are, so if you need additional performance from your bike and are not dedicated to keeping it original, then persue the other options, you will be able to find help on tuning emulators or fork swap or installing a second front disk with someone here...in that I'm not your guy.

Also ask yourself how soon you want to ride again, do you have the patience to go through with the learning experience of a fork swap or tuning emulators?

As far as the headstock bearings go, how long ago were they replaced?  If you don't know, it's time.
Good luck with what ever you choose.

[RodPlunger]

The bike is new to me... So I am guessing they are stock.

I'm not in a huge rush to get on the road as it is sub freezing here right now. I would just rather do a rebuild/ swap now, then have to do it twice.

Also, if I swap forks for a modern pair, what all is involved with making a wheel fit? I would like to use the OEM's after I relace them, but have seen some issues with getting the right spacers and axle.

[Bankerdanny]

So I get the goal of wanting to make it handle, the question is, are you a good enough rider to feel and/or take advantage of the difference.

if realistically your time is spent on mostly straight roads with an occasional curve thrown in then fresh seals and fork oil will give you a ride you will be quite happy with.

Something like the GSXR front swap looks cool, but is quite a bit of work not to mention cash. It will definitely enhance handling, but most of that benefit would be felt on the track.

[calj737]

Drain the fork oil, replace the seals and stem bearings with tapered. If you want improved performance, upgrade the fork springs with Progressive rates and make certain your fork oil is filled properly, with quality fork oil. 

As for a GSXR front end swap, it boils down to 1 of 2 choices;
1. GSXR front end and custom hub, replace rims and spokes/tires (keeping rear stock). This gets you dual discs up front, drum in the back. Cheaper solution and sticking with spoked wheels.

2. Upgrade front end with GSXR and use mag wheels. Easy bolt on up front, but now you have to contend with swing arm changes in the rear, plus modifications to support rear disc brakes. More expensive, more complicated solution.

Personally, I'm just about underway on a 500 with a GSXR front end swap and I've done a fair bit of effort on finding and sourcing my parts. But this option is being done mostly to support a design direction and improve performance. Street bike riding only, so the stock (properly maintenanced) would also have been fine.

The only "opinion" I'd register with you is this: these bikes have reasonably limited HP and if in good maintenance, and being run on the street, the stock brakes and shocks are very well-suited for normal/average riding. If you want upgrades, undertake them sensibly and determine in stages the effort versus the gain and expenses.

Whichever way you go, there's tons of very experienced folks on here to lead the way and answer your questions.

[RodPlunger]

So I get the goal of wanting to make it handle, the question is, are you a good enough rider to feel and/or take advantage of the difference.

if realistically your time is spent on mostly straight roads with an occasional curve thrown in then fresh seals and fork oil will give you a ride you will be quite happy with.

Something like the GSXR front swap looks cool, but is quite a bit of work not to mention cash. It will definitely enhance handling, but most of that benefit would be felt on the track.

I have put roughly 1ook on BMW bikes riding all across the country... Will I be riding this one to California and back? No, but I do love me some sport riding, so an improvement in handling would be fine, but not at the cost of $1000+ in parts and headache.

Also having to deal with the entire wheel swap either front or back, is probably more than I really want to undertake as well. So, I will be rebuilding the stock forks.

 

Drain the fork oil, replace the seals and stem bearings with tapered. If you want improved performance, upgrade the fork springs with Progressive rates and make certain your fork oil is filled properly, with quality fork oil. 

As for a GSXR front end swap, it boils down to 1 of 2 choices;
1. GSXR front end and custom hub, replace rims and spokes/tires (keeping rear stock). This gets you dual discs up front, drum in the back. Cheaper solution and sticking with spoked wheels.

2. Upgrade front end with GSXR and use mag wheels. Easy bolt on up front, but now you have to contend with swing arm changes in the rear, plus modifications to support rear disc brakes. More expensive, more complicated solution.

What springs should I be looking for? Also, I agree with your assessment as to the ultimate reality of the machines we are dealing with here. 50 BHP isn't really set up for pulling the bark off trees.

[calj737]

I used Progressive Springs and am very happy with them coupled with new Progressive HD shocks. Suits the bike really well.

+1 on the high mileage on BMWs. Put over 420k on two different bikes together traveling across this wonderful country.

[RodPlunger]

I used Progressive Springs and am very happy with them coupled with new Progressive HD shocks. Suits the bike really well.

+1 on the high mileage on BMWs. Put over 420k on two different bikes together traveling across this wonderful country.

Wow, that is a lot of f'in miles... 

Do you have a link for the spings and shocks you used? Thanks!

[flybox1]

http://www.progressivesuspension.com/productsearch.aspx

I got my progressive springs through amazon for about $70
steering bearing kit $35 on amazon as well.
Hagon rear shocks were $200 through davequinnmotorcycles.com
all of these were a huge improvement over stock, and can be done in one day I might add.

[RodPlunger]

http://www.progressivesuspension.com/productsearch.aspx

I got my progressive springs through amazon for about $70
steering bearing kit $35 on amazon as well.
Hagon rear shocks were $200 through davequinnmotorcycles.com
all of these were a huge improvement over stock, and can be done in one day I might add.

It seems they have standard and HD (heavy duty) versions. Which did you go with? Thanks...

[flybox1]

I went with the standard ones, and am very satisfied

[calj737]

I used HD shocks for the rear to accommodate more weight and provide a bit firmer feel. All my BMW miles were on K bikes so I'd like to approximate that ride as much as possible. If your weight is less than 180lbs, standard should be fine. If you're a full grow'd man, then I'd recommend HD rear shocks.

I bought all mine thru Dime City (forks and shocks)