Fork springs

First topic message reminder :

Hi,
This is my first post.
I'm from Montreal, Canada. I just bought a used 600 Honda Silverwing FSC600A with one thousand and fifty kilometers.

I just had my 2006-Silverwing's forks rebuilt with Honda parts, new oilseals and dust seals, c clips, washers under the seals and Amsoil fork oil. The thicker oil they sell as opposed to their lighter weight. The shop said for safety that I should change the fork springs after they did the job. The scooter only has 1,050k. One thousand and fifty kilometers. Does anyone think there not familiar with the way the forks are with this bike? Or are they trying to make me spend money unnecessarly? They said I would have to spend all the money over again to rebuild the front shocks. If I did do it couldn't the springs be put in from the top with out taking them off the bike? What fork springs would be a good choice? Thanks members for you help.

I fitted the RT 0.85kg/mm fork springs and 10W oil at 130mm depth. The RT instructions suggest 15mm preload, and the RT springs are much longer than stock, and needed only an additional 5mm of spacer beyond what you get from the washer and the fork cap. I used 3 large washers and got the right preload. I was able to screw the caps on by hand as little extra pressure is needed to overcome the preload.

The spring rate and ride height are really good, not much fork dive under brakes, and no evidence of bottoming. With the added spring rate, the rebound is too light with 10W and I will probably move on to 15W.

I'm still not happy with my forks, they are better with the new springs but I get a shudder through the front end on bumps which I don't understand, feels sort of like the forks binding yet they move very freely when the bike is at a standstill. I think I will be disassembling the steering head for an examination.

Loosen the pinch bolts and bounce it then retorque bolts. Honda service manual says to tighten one cap then tighten other after fork compression. Don't remember left or right but I never did this left both loose after torqueing axle bolt then bounce and tighten caps.

Jack front up and see if there is any steering bearing play or binding. Stock bearings a ball type but tapered ones are out there. All Balls makes them.

I looked at parts of fork little spring in bottom " oil lock and piece oil lock " misunderstood what spring you were showing. Not sure what it does either.

Fork oil can be mixed as long as same brand to change weight. 10w-15w 50-50 12.5.

I had the bike right apart today, pulled the steering head apart and checked the bearings, cleaned and re-greased and then carefully tensioned the bearing. Might have been a tiny touch loose before. Nothing obviously amiss here, a little corrosion in the top ball bearing and it moves smoothly, but nice to check it out myself. I changed the fork oil up to 15W and also replaced a fork seal, the forks are nice and smooth but the top bushings could be replaced as there is a little scoring.

When I was putting the forks back together I checked the balance of my front wheel; this was just mounted loosely in the forks (not a proper balance stand) but showed a definite heavy spot so I added 15g weight to fix that. A bit disappointed  as I had taken the wheel back to the dealer as the tire supplied had a "hop" that I wasn't happy with, and they replaced it and "balanced" the wheel last week.

Thanks for the suggestions on aligning the forks, I learned all about that in 1980-something from a Motorcyclist article called "Let's Get Something Straight". The idea is to let the right fork clamp (which can slide side to side on the axle) find the position that gives the free-est fork movement, so the sequence should be axle, left clamp and then right clamp.

And so to the test ride...MUCH, MUCH better; the wheel balance made a big difference and the ride was much more controlled and in no way harsh. The bike is also steering better than it ever has and the bars have nearly no shimmy at any speed, where they were a bit wiggly at low speed and the bike was pulling a bit to the right before. Feels like a light steering motorcycle now. Pretty happy now.

That's great! So I guess you left out the Honda spacer. Did you use the Racetec washers it comes with?

Yes I did, I also had some other washers from previous purchases, the source doesn't matter, anything from a hardware store that is the right diameter would be OK. You could also cut a thin spacer off the PVC tube supplied, but a stack of washers seemed easiest to me.

Mech 1 twa wrote:

I looked at parts of fork little spring in bottom " oil lock and piece oil lock "  misunderstood what spring you were showing. Not sure what it does either.

This is a photo of the bottom of the damper rod as it would sit into the oil lock piece, with the spring trapped between them. The oil lock looks like it could move slightly up and down (5mm?) on the damper rod, so I now think the spring's function is to hold the oil lock down down and also to allow a little wiggle room for alignment with the end of the stanchion when it is at full compression. But that's just guesswork on my part.

Cosmic_Jumper wrote:

With all the talk about RaceTech springs... Hyperpro springs have been the go-to front suspension upgrade for years. Is there a reason why you all are focused on RaceTech rather than Hyperpro springs?

Nevertheless, I sure like to hear about those damper rod Emulators as well, whether they’ll be an improvement and whether they’ll fit with HyperPro or OEM springs.

Keep the info flowing, please.

To answer the spring brand question Tim, I've had a fair amount of personal experience with Race Tech straight rate springs in my other bikes so they are a known commodity; they are also (for me at least) a lot cheaper than Hyperpro; for the latter I've only found kits that also include oil which makes the international shipping more expensive too.

Regarding the Emulators, one thing that occurred to me with my new spings is they are MUCH longer than stock and so need only 5mm of preload spacer, where the stock springs had something like 70mm. Emulators sit between the top of the damper rod and the bottom of the spring so add some length overall, and I think even with no other peload spacers in the stack, there will be too much preload with the Emulators installed. I've sent an email to Race Tech to query this one.

Thanks Terry. I suppose that the Emulators wouldn’t work with HyperPros then. Hyperpros extend ~3 inches above the fork tube. It can be a bit of a struggle to get the fork caps back on.

With the RaceTech straight rate springs, I can easily install the fork caps with only hand pressure and no tools. That's a difference between a straight rate and progressively wound spring too.

That's something to consider Preload with different springs. I do remember having a good time screwing fork caps back on with Hyperpro springs but only needed a socket in hand to start the threads. Very easy to damage the aluminum cap -- steel tube and a very fine thread . I don't remember how far springs needed to be compressed before cap was close to tube. AHHHH!

Race Tech provided a response to my query:
"You are not missing anything. Scooters can be a challenge due to forks being shorter than motorcycles. The FEGV S3801 Emulators are 15-20mm tall, as such preload would be increased. This may or may not prove an issue? You may wish to try it out & see? Other options are custom made spring set or having your current springs shortened, however this must be don by a professional will make the springs a bit firmer.
Matthew Wiley
Race Tech Vintage Specialist"

Terry Smith wrote:

Race Tech provided a response to my query:
"You are not missing anything. Scooters can be a challenge due to forks being shorter than motorcycles. The FEGV S3801 Emulators are 15-20mm tall, as such preload would be increased. This may or may not prove an issue? You may wish to try it out & see? Other options are custom made spring set or having your current springs shortened, however this must be don by a professional will make the springs a bit firmer.
Matthew Wiley
Race Tech Vintage Specialist"

So basically what they are saying is ............ we have not got a clue, please keep buying our products bud & send us feedback accordingly so that we can profit from your expense while saving money by doing our own research.

That ^^^^ .....

Or you could just accept that Honda have already spent a large amount of money to find the best comptomise, agree with their findings & get on with the bigger issues in life

I'm saying it again AHHHH! 15-20MM is a lot of preload on a Hyperpro already long spring. Terry you had to add 5MM to RaceTech spring maybe a softer spring with more preload would be a good option with Emulators. Spring length won't change but it's compressed a little more. I doubt it will ever bottom and setting sag it important. The springs you got were a different rate that's odd a compromise to get the desired rate.

OE springs and proper spacer cutting would be an option with Emulators. BUT a longer spring progressive or not gives longer fork travel before coils bind. I've felt fork bottom once in bumpy turn it's not a good feeling once front starts to slide.

In terms of suspension set-up, my understanding is that you are always best to get the spring rate right first, and then adjust the damping to suit. A softer spring with more preload can actually feel harsher than a harder spring with less preload, so that is always the direction I'd prefer to go.

I used the stock spring spacer plus around 5.5mm of other washers so I figure I can lose about 7mm of preload by leaving those out. If an Emulator was around 15mm, then that is just 8mm more preload and I figure I could live with that.

I'm planning on leaving the suspension alone for a bit and seeing how it works over a variety of roads. It did not feel harsh on a my relatively short test ride.

I took my bike out for a good test run last night, a mix of urban, motorway and bumpy country roads, over a couple of chilly and dark hours. The bike now feels great, so much safer than it used to and is no longer wandering or bouncing on undulations and bumps.

What I do think is that the front end is extremely sensitive to steering bearing setup. I was reasonably confident that it was suitably adjusted before (based on wriggling the forks and moving the steering side to side with the front end jacked up), but I did fully disassemble and clean the bearings and then re-tensioned the bearing very carefully, erring on the tight but not-too-tight feel. (I've overtightened a steering bearing on my RF900R and THAT was an interesting experience that I don't want to repeat).

I also re-balanced my front wheel, as I'm sure the supplying dealer messed that up badly. Gone is the headshake and unsteadiness that I felt at all speeds. In conjunction with the new springs and the 15W oil, the front end is now steady and trustworthy at all speeds (including go to jail speeds), and the front end is a good match for the Hagon shocks on the back.

Great to hear you're happy with SW.

I'm thinking not a bad idea to check steering bearings at 27K  miles now and it seems to shake more than it used to on deceleration even with a new tire.  Ball or tapered  bearings don't need a lot of preload just snug it a bit.


How are you checking tire balance? Just using axle bolt supported on something?  I've been using a Marc Parnnes  balancer for years on many bikes. Check it out.

SW uses some different adapters but works very well. A little time consuming but I've found it very accurate . Dealers S--K.  

Had a tire mounted at dealer this spring. Put it on backwards the first time and failed to balance it properly after I checked it.   Covid 19 BS or I would have done everything myself. Saved a lot of $$$$ doing it myself over the years.

Mech 1 twa wrote:

Great to hear you're happy with SW.

I'm thinking not a bad idea to check steering bearings at 27K  miles now and it seems to shake more than it used to on deceleration even with a new tire.  Ball or tapered  bearings don't need a lot of preload just snug it a bit.


How are you checking tire balance? Just using axle bolt supported on something?  I've been using a Marc Parnnes  balancer for years on many bikes. Check it out.

SW uses some different adapters but works very well. A little time consuming but I've found it very accurate . Dealers S--K.  

Had a tire mounted at dealer this spring. Put it on backwards the first time and failed to balance it properly after I checked it.   Covid 19 BS or I would have done everything myself. Saved a lot of $$$$ doing it myself over the years.

My dealer has a static balance stand with the necessary fittings, but made a mess of it (or forgot). I balanced my wheel with the axle loose in the forks, the bearings are nice and free and the dust seals on the spacers are worn enough not to drag. I know all of that is not ideal (and might have introduced some unwanted friction) but even so it was very obvious that the wheel was out of balance. I was fortunate to have a small selection of previously used stick-on weights that I could attach with masking tape to test, and then used some good double-sided tape to finally fix. My test ride last night confirmed that the front wheel may not be perfectly balanced now but it is night and day better than it was.

I actually did some online shopping for a balance stand and found a complete stand plus shipping for cheaper than just the shipping cost of the balancer that you linked to; I suspect the vendor may have messed his listing up. The Marc Parnes product looks really nice however.

Oh well shipping to Auckland could be quite expensive. It's a great tool balances to 2 grams if you have enough patience and cut stick on weights carefully.

Mech 1 twa wrote:

Oh well shipping to Auckland could be quite expensive.  It's a great tool balances to 2 grams if you have enough patience and cut stick on weights carefully.

I'll put that on my list of wish tools. I was also looking on Aliexpress, and you can buy a bare shaft plus cones, plus a pair of two-bearing supports for about $40, which looked like it would fit nicely onto a typical rear race-stand (which I already own). However the complete balancer that I ordered was only $25 delivered!!!

Remember, he who dies with the most tools (or toys) wins...