Replacement Forks/ Rear Shocks?

[adarngoodjoe]

I've got a relatively stock 88 454 LTD with no mods. I'm not interested in really deviating from the factory look. I'm not trying to mod the bike to anything other that what it was originally designed. All I'm really looking for is a serviceable bike to ride.

Having said all that, I've had to replace the fork seals twice in less than 1k miles. The inner fork rods were rusted and pitted from neglect and sitting outside. I wire brushed them and tried to clean off any burrs so that the seals wouldn't be torn again. Each time, the forks would last for a spell before a drop of fork oil would appear on the dust seal. After more riding, the drop would turn into full blown leaks that run down the outer fork legs when I let the bike sit overnight. Needless to say, I'm over it and went to looking for replacement forks.

I searched the forums and came across several threads that suggested the Vulcan 750 forks and earlier model Vulcan 500 forks were compatible with our 454s and should bolt right into our triple trees. Went to eBay and found a super clean set of Vulcan 750 forks from a 2000 Vulcan 750 with low miles and promptly made the purchase. When they arrived, I noticed right away that they were slightly thicker in diameter than my stock forks. I don't have metric calipers but my stock forks measured somewhere around 35-36 mm. The forks I purchased measured 1.5" or basically 37-38 mm.

Am I missing something or am I misinformed? I wasn't looking to change out the triple tree in order to make these work.

I checked parts schematic for the Vulcan 750 and it appears to have the same part number for the fork assemblies going all the way back to the 1980s.

I tried spreading the fork clamps out a bit to accommodate the larger fork tubes but I don't see how I can get that much spread from the cast metal before stressing the part and weakening it. Even if I could spread it open enough, It looks like I'd have to pound it into the triple tree to which also doesn't seem right.

[eaglerider]

454 forks are 37MM.

[adarngoodjoe]

I'll have to take your word for it. I don't have metric calipers. The remainder of this post will be what I've managed to learn and unable to find in other threads for anyone else who might stumble upon this.



The Vulcan 750 forks I purchased are larger in diameter. I ended up purchasing the triple tree (or steering yoke) from a Vulcan 750 and swapped out my triple tree. I didn't want to go that route originally but I'm glad I did. I didn't realize my steering yoke (triple tree) was loose. It looked as though it was never disassembled or serviced. My steering is night and day different (buttery smooth). A lot of my windshield buzzing and handlebar vibration (that I assumed was normal) went away.



The Vulcan 750 and 454 steering yokes share the same bearings/races but there's geometry differences on the bottom of the yokes. The Vulcan 750 yoke turns way farther on my 454 frame than my factory 454 yoke due to the differences in the cast "bump stops". It now contacts some of the plastics covering the radiator, radiator filler neck and radiator overflow tank. I don't think it'll really be an issue, but it could be I suppose if I were to harshly crank the handlebars to full extension on either side. All the steering yoke bolts and instrument cluster are interchangeable.



After replacing the fork seals and fork oil (Bel Ray 15w), I have to say. The Vulcan 750 forks ride way better than my 454 forks. I’m currently without a front brake though so I haven’t really had the opportunity to go on a ride yet other than slowly around the yard.



Probably one of the best parts about swapping yokes and forks is that I now (as of this posting) have access to current production parts that are still new and in circulation.



Now on to my rear shock absorbers. They are shot. I’m thinking of going with Progressive Suspensions 412 series shocks and sticking with the factory length shock. It’s a progressive shock and reviews seem to be favorable over most OEM shocks from various manufacturers. They are cheaper than new OEM replacements but not exactly inexpensive. I read a lot of post about the Suzuki Savage/ Boulevard/S40/LS650 shocks being a direct bolt on. I’m just not currently wanting to lower or change the handling characteristics regarding rake, both fore and aft.

[eaglerider]

Apparently, you have late model Vulcan 750 parts.

[adarngoodjoe]

Mar 23, 2020 19:19:35 GMT -6 adarngoodjoe said:

Now on to my rear shock absorbers. They are shot. I’m thinking of going with Progressive Suspensions 412 series shocks and sticking with the factory length shock. It’s a progressive shock and reviews seem to be favorable over most OEM shocks from various manufacturers. They are cheaper than new OEM replacements but not exactly inexpensive. I read a lot of post about the Suzuki Savage/ Boulevard/S40/LS650 shocks being a direct bolt on. I’m just not currently wanting to lower or change the handling characteristics regarding rake, both fore and aft.

I ordered and installed Progressive Suspensions 412 series shocks on my bike. The specific model or SKU I purchased was 412-4210C. It's a 13" shock so it mirrors the factory shock length. It's what Progressive Suspension recommends as a factory replacement for our bikes anyway. When I sit on the bike, it compresses to the 11.75" as recommended by Progressive Suspension. I weigh 205lbs currently for perspective. It's supposed to be a progressive spring setup.

The shocks came with all the hardware necessary to mount. I had concerns about the bushings provided initially, but they ended up fitting just fine. I had to remove both factory shocks at the same time in order to install the new ones. I had to readjust my final drive belt as well. I guess the new ones are a half inch or inch longer (assuming my stock shocks aren't shorter just because of spring set). The bike does sit a little bit taller than my old shocks. I assume there will be a little spring setting after I've had a chance to really put some miles on the new ones. The chrome on black looks good for those of you with a stock bike setup. The bottom spring seats on the Progressive Suspension shocks aren't tapered like our factory shocks.  The reason I mention it is because there is a little contact with the muffler when the shock is at full extension. That's not the case when I sit on the bike though. I didn't have to remove my mufflers during install but it did take a little wiggling to make it work. I used a ratchet strap over a ceiling rafter in my shop to hold up the rear of my bike so it didn't collapse on the rear swing arm during install.

Progressive Suspension sells shocks for all kinds of bikes so I assume you could buy a shorter shock and lower your bike if so desired (Think their Suzuki S40/LS650 shocks).

As for the ride quality, I can only compare it to my blown factory shocks. With that in mind, they are a fantastic upgrade for the $270 I paid for them on eBay. Between the Vulcan 750 forks and the Progressive Suspension shocks, my bike rides super smooth down the road now. It really does make for a much better ride on my old foam seat. I did not realize how little dampening my old suspension was doing or how much vibration and bumps were being transferred into my back and bottom from the bike. I would say the bike feels very planted, appropriately dampened and not floaty at all. I used the Bel Ray 15w in my front forks. I've used Maxima in the past in the same weight. I would say  the Bel Ray fork oil is a better product and worth the cost over Maxima.

I went ahead and added the Vulcan 750 dual rotor setup to my bike as well. Again, I now have common parts in circulation if I need to replace anything like my master cylinder. Braking is much improved. I managed to find a black front rim in a local junk yard for $20. A little "bar keepers friend" cleanser and oil cleaned off a lot of the corrosion and made it shine up nice. I recommend anyone spray a light lubricant like G96 or CLP on their black painted parts (engine, wheels...not tires) in order to add new life to the faded black paint before you go spraying new paint on. Anybody wanting to swap to the dual rotor setup will need to pickup the Vulcan 750 horn bracket as well if you plan on leaving your horn and fuse block in the same spot on the forks. The 454 bracket is shaped differently and doesn't sit correctly when mounted over the brake line splitter that is mounted underneath it. The screws attaching the brake line splitter are also slightly longer too.

Another thing worth mentioning with regard to the Vulcan 750 front fork setup. If you do plan on switching out to a Vulcan 750 front fork setup, you will need to buy a Vulcan 750 brake rotor if you plan to keep using your 454 front wheel single rotor setup. I learned the hard way that the single 454 rotor is slightly bigger in diameter than the Vulcan 750 rotors. Both bikes use the same caliper but i think there is a slight geometry change in how the caliper mounts to the fork which requires a smaller diameter rotor on the Vulcan 750. I assume your braking power would be less with smaller single rotor setup so I don't know that I would recommend it. It could be done in a pinch though.

In summation, in order to convert your entire front end to a Vulcan 750 in entirety, you'll need to get the Vulcan 750 steering yoke (triple tree), Vulcan 750 front forks, Vulcan 750 front brake setup (master cylinder down to the calipers), front wheel from Vulcan 750 (older ones from early 90s are painted black like 454) with the Vulcan 750 rotors, Vulcan 750 horn bracket with longer bolts and the Vulcan 750 front brake line holder brackets. Everything else should bolt on fine. I found most of my parts on eBay for fairly reasonable prices. Most of my front end is now from a 2003 Vulcan 750.

[steamy]

Nice write up