I’ve owned my Honda VTR 1000 SP2 for about 11 years now, since 2008. Back in 2010, after a bumpy and extended trip in the Swiss Alps and Italian Dolomites, one of my front forks started leaking a bit. I took out the forks, a race shop serviced them, and that was that: brilliant ride quality. 2 years later though, the left leg started slightly leaking again. Not a lot, but you could see a slight oily film on the inner leg. I brought it away for another service, they checked it and replaced the seals again. Fast forward another 3 years and.. yep.
At that point, I was slightly fed up with spending €150 for a seal service every 2-3 years. And more importantly, taking the forks out of the bike every 2-3 years. I looked up how difficult it was to do a Honda VTR 1000 SP2 front fork service myself. Turns out, there’s a bunch of things you can do wrong and wreck, but it’s not rocket science! Queue a DIY front fork service!
Disclaimer & Tools
So first of all, a disclaimer. A front fork is a vital component in a motorcycle. The Honda VTR 1000 SP2 front fork is rare, as it’s out of production for quite some time and people tend to ride the remaining bikes into objects. There’s a lot of delicate components in a fork that you can break if you apply the wrong force to it. Replacing them with new parts will be very expensive or even impossible. So be careful; for both your wallet and your own safety. The instructions here serve as a rough guide. If you break something, or if the front fork disassembles itself while you’re riding your bike, don’t blame me.
With that out of the way, you will need some tools to successfully service your Honda VTR 1000 SP2 front fork, or any fork for that matter. One of them is a seal driver. I bought the Sealey MS016 Front Seal Driver. It can be adjusted for any fork between 35 and 47mm, so is a good investment when you expect to service other forks in the future. The Honda VTR 1000 SP2 front fork is a 43mm USD (upside-down) fork. You could also improvise a seal driver out of two halves of plastic pipe, just be careful that you don’t damage the new seal.
Next, you will need a torque wrench. Avoid over-tightening parts, since they are typically made out of light materials that easily break. You will also need a standard set of wrenches, ratchets, screwdrivers, a oil drain pan, etc.
For consumables, you need seals and fork oil. You’ll also need a couple of rags to wipe things down.
Disassembling the Honda VTR 1000 SP2 front fork
First of all, take the front fork legs out of the bike (don’t lose the stopper ring). Note how many rings/grooves are visible above the top fork bridge; this tells you how low the fork is in the bike, and the pitch that the bike is at. It influences the driving stability and steering responsiveness: more rings visible means the front of the bike is lower, and the front forks are closer to vertical. This translates to a bike that is more responsive, but also more nervous. The opposite makes the bike more stable, but also requires more effort to turn it into a corner.
Here’s a piece on motorcycle geometry. Mine is leveled out at the (standard) top ring; see the little groove in the photo on the right. Which is probably a smart thing, since I ride regular roads and don’t want my bike to throw me off when hitting a bump.
Apart from the workshop manual, I’ve used the video below to help me through a few of the general steps. Have a look at it; he explains it really well.
Once you get the forks out of the bike (I recommend working on one fork at a time), you need to disassemble it. Unscrew the top, taking off the black preload adjuster. Next, unscrew the blue fork cap from the outer tube. Don’t be afraid, there won’t be any springs popping out since it’s an USD fork. With this action, you’ll simply lower the outer tube, allowing you to drain the oil. Tip it upside down, drain the oil into a suitable container. Dispose of this old oil properly by bringing it to a waste recycling center of some sort. Please don’t tip it in the drain; it’s toxic and you don’t want it in your drinking or swimming water.
Next, we need to remove the top assembly of your fork. In the Youtube video that’s done at around 10 minutes into the video. This is the only hard part to be honest, as that locking nut is obscured in a VTR 1000 SP2 front fork by a white, plastic spring collar. There are two holes in that spring collar, so you can (with some modifications) hook a ratchet band into it and slowly lower it. This is also the reason why I don’t have any pictures of this process, as I needed both hands and a foot to do this. Or you could ask a mate to help you.
Whatever you do, be very careful; you do not want to break the spring collar, or more importantly, damage the damper rod that’s behind it. The spring collar needs to be lowered quite a bit, until you see a locking nut. Put a wrench on it, and you should finally be able to unscrew the blue fork cap. You should now be able to take the spring out and, with the fork upside down, pump the damper rod a few times until all the residual oil has drained.
Next, you start to remove the seals and bushes. Start with the dust cap and the stopper ring and pry them loose. Once those are off, take the bottom of the fork/slide pipe and the outer tube and pull it apart with a couple of quick successive motions. Don’t go all HULK SMASH! on it; you want enough force to pop the seal out, but not so much that parts fly everywhere. Once that’s done, remove the slider bushing with a screwdriver, remove the guide bushing, back-up ring and oil seal. Finally, remove the stopper ring and dust seal that you loosened before. You should end up with a nice collection of parts:
Clean, inspect and replace/repair where necessary
Next, wipe down and clean your fork parts, and inspect them. Check for cracks, burrs, dents. My dust seal still looked good, so I reused it. Same for the bushings: there shouldn’t be excessive scratches or scoring on it. Officially, if the teflon is worn so that you can see copper on more than 3/4th of the surface, you need to replace them. Mine looked good/new:
What was a problem in both my forks (but primarily the left one, which was leaking first), was a couple of pits and sharp pointy flakes in the chrome of the slide pipe. I had to inspect the slide pipe 2 or 3 times, both visually and by touch, before I spotted them. You can imagine what happens when sharp parts of the slide pipe move through the oil seals of the fork; it perfectly explains why it started leaking again so soon after the previous service.
To repair it, I’ve sanded the affected area down ever so slightly with some 200-250 grit paper. You can see a similar process in the video at around 17 minutes. It took away the sharp, raised edges of the holes, but obviously doesn’t repair the chrome in that little hole. Sand it down just enough so you don’t feel any raised edges anymore, but leave as much of the chrome in place. You definitely shouldn’t feel any grooves from the grinding afterwards. Wipe everything down again, give it one last inspection top to bottom, and once your satisfied we can reassemble the fork again!
Reassembly of the Honda VTR 1000 SP2 front fork
I bought some new Ari fork oil seals from a local shop, and 1L of Motul 10W Fork Oil. The oil meets the OEM specs. I’m pretty light myself at ~64kg without gear, and this setup is still relatively stiff for the road riding I do. I am tempted to add some 7.5W oil into the mix during the next service (equal parts 10W and 7.5W), but we’ll see.
Before we begin, wrap some sturdy yet thin plastic around the bushing groove on the slide pipe to protect the new oil seal, and lubricate it with the supplied rubber lube or some new fork oil. If you drag the new seals over the grooves, you will damage them. The video again shows you this at around 23 minutes. Next, slide on the dust seal, the stopper ring, and finally the new oil seal. Coat the inside of the oil seal with rubber lube (usually supplied with the new seals). It should go on the slide pipe with the chamfered (or angled) side oriented to the bottom of the fork. Next, remove the plastic and install the metal backup ring, the guide bushing and the slider bushing. If there are any burrs on the bushings, remove them but be careful that you don’t damage the teflon coating.
Install the slide pipe into the outer pipe, and use the fork seal driver to install the guide bushing, back-up ring and oil seal. The video shows it well at 26 minutes. You should see, hear and feel the oil seal reach its final position, and you should also be able to see the groove where the stopper ring pops into. Install the stopper ring with a small screw driver, and pop in the dust seal as well. All done on the assembly part!
Fork oil and bleeding air
Rotate the fork right-side up, and wrap an old t-shirt around the slide pipe. This prevents it from bottoming out in the next steps, and damaging the seals if your slide pipe is pitted. Compress the fork almost completely. Take the fork fluid and pour it in until you have approximately an air gap of 135mm from oil to top of the outer pipe. The manual states you need approximately 498ml (or 16.8 US oz/17.6 Imp oz) for an Honda VTR 1000 SP2 front fork. But that’s without ANY oil in the fork; and we still have residual oil left in the damper. So add less (maybe 450ml), and top up later.
Next, extend the fork (no more than 305mm, or it will spill), cover the top of the outer tube with your hand, and slowly compress the fork. Remove your hand, extend the fork, cover it again, compress. Repeat this for a few times: the manual states 2-3 times, but go nuts and do it 5-10 times if you like.
Once done, pump the damper rod in the outer tube slowly for 8-10 times to bleed the air from it. Compress the fork and damper again, and leave it standing for 5 minutes to ensure all the bubbles rise to the surface. Measure the air gap from the top of the fork to the oil level again, and adjust it until you have 135mm / 5.3 inches. You can play with the air gap if you like; increase it or decrease it, but it will affect the final ride characteristics.
Once happy, pop in the fork (make sure it’s clean!) with the tapered side up. Slide on the white spring collar, ratchet it down, extend the damper and screw the fork cap to it, in reverse order of disassembly. Tighten the locking nut on the damper and the fork cap together with 34Nm of force. And finally, hand-tighten the fork cap into the outer tube and install the pre-load adjuster and ring. Why hand-tighten? You have no surface to grip on the outer pipe, so it’s difficult to tighten it to the correct torque by hand. We’ll tighten it up fully once the fork is back into the bike.
Install the fork (don’t forget the stopper ring!) back into the bike, lining up the groove with the top handlebar. Tighten the bottom bridge pinch bolts with 26Nm. With the fork now partially tightened in the bike, it’s easier to tighten up the fork cap to the correct torque, which is 34Nm. Do so, and finally tighten the top bridge pinch bolts with 26Nm. Now repeat these instructions on the other fork leg, reinstall the wheel and brakes, and take her out for a spin!