Tusk D-Sport Tires

My recently purchased (used) 2012 Suzuki DR650 came with a set of Shinko 804/805 Big Block Tires (40% on road/60% off road). The 804 (front) was near new, the rear was a thousand miles away from replacement. 

I'm very familiar with the Shinkos. I had a set on a past KLR650 and the Shinkos were the tires that I purchased to replace the Original Equipment Tires on my former 2016 Suzuki DR650 that I purchased new. My problem with the Shinkos is, bottom line, I never liked them; not so much the 805 (rear) as the 804. Likely a great tire for more intermediate terrains, such as gravels and hardpans, the 804 isn't suitable for the soft sand, loam, mud that we have in Florida. Here are the Shinkos on my 2016 DR tearing up a muddy trail out on Devils Creek (Brooksville, Florida).

Notwithstanding my feelings for the Shinko, I gave them, as installed on my recently purchased DR, a shot on the 500 mile Trans Florida Rally in mid-November, first rally on the 2012 DR. Only to confirm what I used to think of them as stated above

So, between the Trans Florida Rally and upcoming Polar Bear Rally, I've slipped on a fresh set of tires more suitable for my needs. Those are the Tusk D-Sports (Front: 90/90-21 $54 @ RMATV, Rear: 130/90-17 $64 @ RMATV). Since RMATV released the D-Sport under it's Tusk Brand, I've had two sets of the D-Sports, these will be my third.

 

The D-Sports are generally believed to fall into the 30% on road/70% off road category of dual sport tires, which seems right based on my experience with them. The tread pattern provides thick knobs that hookup and wide/deep grooves that channel the soft materials out the sides, thus maintaining traction on the sandy and muddy Florida trails and forest roads. 

Online reviews and comments can be found that suggest the D-Sport front isn't effective on soft surfaces, basically capable of washing. Well, all tires wash in sand and mud, but as a generality, those comments are simply not true. All you need to do is look at the tread pattern to see that those comments are wildly exaggerated. I believe the reason behind disparaging comments about this tire (and certain others) are that the comments are coming from riders that don't have experience riding in sand and mud as do I. That stuff is difficult for everyone.

The D-Sport tire compound seems very similar to the D-606 and has a consistent wear life to the Dunlops. The D-Sport carcass is relatively stiff compared to other aggressive DOT knobby tires such as the Kenda K760 TrakMasters, but I find it's stiffness to be similar to the D-606. 

Online reviews and comments that indicate stiffness to the point of difficulty in spooning or limited air-down levels are wildly exaggerated. I've spooned three sets with my basic hand spooning tools outlined for you below, no problemo.

As for on-road, the D-Sports, like the D-606 and K760s, are a long way from a smooth ride on the pavement. Rough and noisy. Similarly, like all other DOT knobby tread designs, caution should be exercised on wet pavement. Other than that, the the D-Sports hold-the-road pretty good. Here are the D-Sports (mounted on my classic 1985 KLR600) sticking to the off-camber hairpin turns of the Tail of the Dragon. 

Onward...

Off with the Shinkos and on with the D-Sports. 

The front, having only recently been installed came off easy; the fresh D-Sport spoon on just as easy. The rear, on the other hand, was a miserable job getting off the bead. Such is the case when they've been sitting a long time and compound wears off on the metal. I would not have been able to break the bead on the trail. It's a good thing I did the change.

Cleaning a rim in this condition this requires a combination of wire wheel and solvent. 

I use the same tire tools in my garage as I use on the trails. Specifically, those are the Stockton 3-Piece Tire Iron Kit ($30 at Revzilla and Cycle Gear) and the very popular Motion Pro Bead Buddy ($17 at many stores). 

Removing the tire carcass requires all three of the tools in the Stockton Kit (see below). The longer bar has a bend on one side for breaking a bead; a normal bead, not like the one I needed my 6" clamp to break. Spooning the tire on the rim requires only the longer bar and the Bead Buddy as shown in the photo above. The Bead Buddy holds the bead in place at one point, then the long bar is used to spoon it on. The long bar in the Stockton Kit is the key to successful spooning. It has a bead breaker bend on one side and a special lip on the other that avoids needing to push the bar under the bead too much and possibly pinch the tube. I never pinch a tube sticking to these two tools. 

Spooning the D-Sport onto the nicely cleaned rim, with a fresh strip and tube, was a cake walk. As I previously mentioned, online reviews and comments that indicate that the sidewalls and carcass are so stiff as to interfere with spooning are wildly exaggerated. .

I'm looking forward to reacclimating myself with the Tusk D-Sports in early January 2022 at the Polar Bear Dual Sport and Adventure Rally. 

Final thoughts on Dual Sport Tire Pricing:

Continental Twinduro TKC80:

When I first got into dual sport in a very serious way, there was only one tire that I consistently used: Continental Twinduro TKC80. I consider the 40/60 class Twinduro to be the gold standard in dual sport tires from a pure performance perspective. Unfortunately, as time passed, Continental took advantage of the tire's popularity and following and all but priced the tire out of the market. While I just paid $118 for the set of D-Sports, a set of Conti's would have run me $250. That wouldn't necessarily be the end of the world; However, the one issue that the Conti's have is a poor wear life relative to other options. In a pure 50-50 road vs trail riding environment, the lifespan of the Conti is no more than 2,500 miles. I will get twice the miles under the same conditions with the D-Sports. 

Look at it like this, if the $132 price delta between the D-Sport and the Conti were projected to an average 10,000 mile year, tire costs would be $264 for the D-Sports (two sets) and $1,000 for the Continentals (four sets). I'll leave out tubes and strips that need to be replaced with every tire change.

Dunlop D-606:

Another tire worthy of mention is the 10/90 Class Dunlop D-606. An excellent dual sport tire, although a more gnarly tread pattern for serious off road work. The D-606s represent another example of popular tires who's price went off the scale in response to a broadening dual sport following. In fact, I was running the D-606 on my 2016 Suzuki DR650 when I sold it in 2016. Like the Conti's, I actually can't remember what I paid for them; however, today the set is $235. I will mention that the D606s actually had an excellent wear life for a 10/90, perhaps the best I've had in that category. 

One interesting observation that I had while reviewing some old photos of my 2016 Suzuki DR650 was how close the 10/90 Dunlop D-606 (right) and 30/70D-Sport (left) Tread Patterns are. From my first hand experience, I think its safe to say that the compound (stiffness) is equally similar.

Shinko 804/805 Big Blocks:

Since this post started with a discussion of the Shinkos, I will add that the Shinkos are another tire where popularity and following resulted in a massive price increase. A set of Shinkos for the DR, although not under consideration for the reasons mentioned, would have run $236. For the record, their wear lives exceed all other tires mentioned in this post.

Rejetting my (Second) DR650

I've just completed tuning (aka jetting) the stock Mikuni BST40 Constant Velocity ("CV") type carburetor on my recently purchased 2012 Suzuki DR650 (15,000 miles) using the James Dean JDJetting Kit No. JDS013. I have experience tuning my first DR650s, although the first involved a new, fresh off the showroom floor, 2016 model. I used the JD Kit on that one as well, based on information and reviews that I considered on the DR650 Forum.

I actually have quite a little experience tuning and jetting CV-type carburetors, having owned the two DRs, two KLRs and two Super Sherpas. When it comes to tuning normally aspirated fueling systems, I believe jetting kits are the way to go. Of course, there are several brands of kits other than the JD on the market for our consideration. In general, though, with jetting kits you typically get the following:

• A selection of Jets: A number of different jets sizes for different applications. The JD Kit came with Mikuni #140, #145, #150, #155 Main Jets and a replacement #42.5 Pilot Jet. With all those jets, the Kit supports future mods.

• Needles: Often kits include a motorcycle specific, or selection, of needles with different lengths and tappers. The JD Kit came with two height-adjustable needles with tappers to fit differing climates and altitudes.

• Guidance on tuning parts selection. 

ProCycle offers a bunch of nice kits, including one of their own design.

Essentially, tuning/jetting a carburetor encompasses configuring the fueling flow level (i.e. amount of gas) and the fueling ratio (i.e. the mix of fuel to air, usually around 1 part fuel to 15 part air) to a motorcycle in either it's stock form or modified form. Tuning/jetting involves selecting a combination of jets, needle, needle height, and fueling mixture. In some instances, it may also other involve physical modifications to the carburetor (e.g. the ProCycle Kit recommends drilling a small hole in the slide to adjust the CV vacuum level).  

Why jet/tune the DR (and many other brands/models)? The general answer is that carburetors do not provide constant and correct air-fuel mixtures to the engines they serve ... period!

• No-Modifications: It is widely believed (including by me) that the stock configuration of naturally aspirated motorcycles is designed too heavily in response to governmental fuel and emission standards resulting an excessively lean fueling mixtures. Tuning a richer mix (more fuel + less air) improves engine performance, but at the cost of fuel efficiency. I jetted my new, fresh off the showroom floor 2016 DR650 for this reason. 

• Modifications: Jetting is considered appropriate and may, in fact, be necessary when modifications are made to the motorcycle design. The BST40 is configured (fitted, so to speak) to work with the stock motorcycle and all it's parts. However, there are changes to the motorcycle that can interrupt that stock configuration (e.g. exhaust, air box, motor cams). The most common modifications are (i) air box modifications and (ii) installing performance enhancing exhaust systems. Modifications have the affect of changing the engine's needs in terms of the amount of fuel, the mix of fuel/air or both. Tuning and jetting adjusts the carburetor to accommodate a better running powertrain.

• Horsepower: NO! As some may suggest, jetting does not increase horsepower. Perhaps whatever modification giving rise to the jetting increases horses. But the jetting itself only reconfigures the carburetor to allow those performance enhancing modifications to work on the motorcycle.

In this most recent exercise, one issue on my recently purchased 2012 DR650 was Airbox Modifications. Generally, airbox modifications involve one or more of (i) removing the snorkel, (ii) cutting a hole in the air box, (iii) removing the airbox door, altogether and/or (iv) adding a hi-flow air filter. These modifications naturally increase airflow into the carburetor. Since the motorcycle engine ignites a specific mix (or ratio) of fuel and air (usually around 1 part air to 15 parts fuel), an increase in airflow will result in leaning the mix. Generally, we don't want to lean the mix, as the factory settings seem to result in too lean a mixture in stock configuration. 

The leaner mix arising from the air box modification requires adjustment to the mixture to "enrichen" by individually or a combination of (i) a larger main jet, (ii) raising the needle height, (iii) reducing the needles taper, and/or (iii) opening the fuel screw (aka mixture screw).

As it relates to my 2012 DR650, both the snorkel and airbox cover had been removed. Carburetor tuning changes by prior owners that I encountered, presumably to adjust the mix for the air box mods, included (i) increasing the main jet from a stock #140 to a #160 (increasing jet aperture and, therefore, fuel amount) and (ii) increasing the fuel to air mix to "richer" by turning the fuel mix screw out from 1 1/2 turns (stock configuration) to 2 1/4 turns. Both of these tuning actions pointed to enriching the fueling mix to compensation for the additional airflow from the modified airbox. 

I decided to replace the airbox cover with a new cover due to the dusty/sandy conditions that I encounter on the trails, but left the snorkel off. In addition, the motorcycle had a stutter/sputter in the upper end of the powertrain that was clearly a fueling mixture problem that needed correction. The condition is a symptom of an overly rich mixture. For these combined conditions, I set out to jet and tune the BST40.

As previously mentioned, I used the James Dean JDJetting Kit #JDS013 on both my 2016 and 2012 Suzuki DR650s; around $85 and available at ProCycle.

Here is a link to the Instructions from the JDS013 Kit. Kit components are:

• Main Jets (Mikuni Brand): 140 (Stock), 145, 150,155
• Pilot Jet (Mikuni Brand): 42.5
• Needles: Blue Coded (Rich), Red Coded (Lean)
• Needle Clip
• 4 Replacement Cap Screws
• Drill Bit for Slide Modification

My final configuration was: 

• 145 Main Jet
• 42.5 Pilot Jet
• Red Coded Needle @ #3 Groove
• 1.5 Turns on the Fueling Screw (note 1.5 is stock)

I followed the guidance in the JDJetting instructions (see link above) related to modification-types, climate and elevation. Jet selection and Fueling Screw adjustments, on the other hand, is and was a matter of trial and error irrespective of their instructions. The following procedural points and considerations may help through the trials:

1. Test Your Mods: Determine the affects of the modifications and performance parts along the entire powerband before jumping into jetting. Don't assume that a new pipe or a air box mod will require re-jetting; they may not. Understand what the affects are with some long test rides. A sluggish/sputtering throttle is the result of an overly rich mixture. Bogging is the result of an overly lean mixture. Jetting is dealing with the amount and mix of air and fuel so defining the issue before fixing it (or not) sort of goes without saying.

2. Clean It: Don't tune/jet a dirty carburetor. Make sure the carburetor on a used motorcycle is properly cleaned before jetting and tuning. Consider the guidance in The BST40 Bible on Adventure Rider. The author of that post did a better job on the disassembly and cleaning that I could do here.

3. Warm it Up: The ultimate tuning decisions and fine tuning adjustments need to be done when the motorcycle is in the state that it normally operates. That is, hot.

4. Ride It: You can not jet or tune your carburetor without taking it out on the road and testing it along the entire powerband. It may run fine at idle or twisting the throttle sitting on the stand. It would be different out on the road and, for that matter, pure luck to get the tuning zeroed in the first time. Consider this, when I used to work at the powersport dealerships our service personnel would advise service customers that the carb may have to be removed up to three times (and re-jetted) following road testing to get zeroed in on the proper tuning.

5. Needle Selection: In my opinion, needle adjustment and selection is low-hanging fruit in the tuning process. The needle, being right in the middle of things going on the carburetor, controls the majority of all throttle settings up and down the powerband. Needle height and taper affect mixture. Lowering the needs or expanding the taper make the mix leaner. Raising the needle or thinning the taper makes the mix richer. The needle taper is not adjustable; rather, some kits (including the JD) offer different needles with different tapers. All needles (for the BST40) have grooves to allow for lowering and raising using a simple C-clip. Start the trek on tuning the BST40 with the C-clip in the middle groove. 

6. Jet Selection: Jet selection governs the amount of fuel based on the size of its aperture (i.e. the hole going through the middle). Generally, the goal of jet selection is ultimately to select the smallest Main Jet (smallest aperture) that supports fueling adjustments necessary for the modifications or objectives. There may, in fact be a range of main jet sizes that seem to work, but fine tuning is going to result in better performance if the smallest in that range can be selected. The fueling screw, as discussed in the next point, can help identify the best jet for the job.

6. Fueling Screw: The fueling screw governs the air/fuel mixture (turn out = more fuel = richer; turn in = more air = leaner). Fueling mix is the "finest" of fine tuning the carburetor. It should be noted that, irrespective of the modifications, the fueling screw should generally be kept at or near the stock setting. In the case of the Suzuki DR650, that setting is 1 1/2 turns out (also the recommended initial setting in the JDJetting Kit). If the tuning requires turning the screw too far out or in from that setting (say 1/2 turn either way), the jet selection is probably incorrect. For example, if I needed to turn the fueling screw out 2 1/2 turns to zero in on a #145 Main Jet, I would bump the jet to a #150 (more fuel flow) and put the turns back to 1 1/2.

This photo ^ shared from The BST40 Bible.

Overall, tuning the BST40 is a process of understanding the affects that modifications have on the motorcycles performance along the entire powerband and then tuning them in. It's important to understand how the individual tuning elements interact in achieving the proper amount of fuel and the proper mixture of air and fuel ... and not going too far.

Receiver Rack Lights

Earlier this year in January, I purchased a Black Widow Receiver Rack (Model AMC-400) to haul my Kawasaki Super Sherpa and am also using it to haul my recently purchased Suzuki DR650.

It was my plan to install auxiliary taillights since the motorcycle interfered with the permanent taillights and just got around to it this weekend. I'd previously used portable (trailer type) auxiliary lighting, but decided to go with something more permanent with this rack.

I selected a waterproof set of Partsam Lights on Amazon for under $20 and wired them up to my trailer light harness that has a basic four pin quick disconnect. 

I didn't want to weaken the rack by drilling holes, but I ended up using four small self tapping bolts to secure the lighting to the rack. I thought of, but then discounted, glue options. I didn't think zip ties or similar would be the answer as loading and unloading the motorcycles may damage the straps. So far, the self tapping bolts look like they're going to do the job.

I believe that augmenting the existing lighting when using these receiver is a much safer arrangement for transport.

Valve Stem Tool

Today's Happy Ending:

You're in your garage spooning tires and can't find a valve stem tool ... of which you probably have ten, but can't find one of  'em. Ya know, kind of like your 10mm socket. 

Glad that I purchased the Kenda Tuff Tubes for this change. They have a valve tool embedded valve embedded right in the valve cap.

Thank you, Kenda!

Onward...

Trans Florida Adventure Rally Part 2

 The first serious work for my DR650 Part 2 (this is my second DR650) was the November version of the 2021 Semi-Annual Trans Florida Adventure Rally, i.e. Part 2. 

The Rally launched out of Palatka, Florida (east cost) on Day 1 and terminated 250 miles later in Monticello, Florida. Day 2 was a different 230 mile track back to Palatka. I've ridden the TF for several years and, while the starting/finish has always been Palatka, the organizers place the mid-point in a different city; normally one of the cities along the Gulf, this track had us all the way up near Tallahassee!

Overall, I estimate a better than 50-50 dirt to pavement ratio, but that still equates to being in the gravel, dirt, sand and dust much longer. I've ridden the Trans Florida for several years and, quite frankly, this event was the best of the tracks they've prepared for us. 

While I stayed in a hotel in Monticello the first night, I had camp set up at Rodman Campground throughout the weekend. A little fishing on Friday and Monday in the Rodman Reserve and Rallying over the weekend.

Light and nimble being the best way to handle these types of events, I stripped the DR650 down to bare bones. No need for boxes and center stands and whatever else. Generally, all I need is one change of cloths and tube replacement tools for the Trans Florida.

I have some video of the starting line in Palatka.

The next event we're registered for is the Polar Bear Adventure Rally out of Keystone Heights, Florida on January 6-9.

Stay tuned.

Bush Pig

This post is copied from the Devils Creek DR Blog.

The Suzuki DR650 has been in production since 1990 with minimal change. At some point along the way, it became known as the Bush Pig.

It's been a little over three years since selling my first Bush Pig, a 2016 Suzuki DR650 (the Devils Creek DR) in June 2018. Yesterday, after deciding to move back into the larger bore thumper, I purchased another DR650. This one is a 2012 model year with 16,000 miles that I purchased in a private sale in Bartow, Florida. 

The seller listed the motorcycle for $5,500 on Facebook Market Place. We agreed on $4,500 for the motorcycle that was loaded with adventure accessories, as follows (some of which the seller was not aware of):

• Acerbis 5.3 Gallon Tank (Seller listed the tank as the Acerbis 6.6 Gallon Tank.)
• Sargent Comfort Seat
• Tusk Panniers
• DirtRacks Sidecase Brackets and Tail Rack
• Pelican Top Case
• RallyWorx Screen
• Barkbuster Handguards
• JNS Bash Plate
• Warp 9 Racing Wide Foot Pegs
• Unknown Brand Accessory Fog Lights
• Sealight LED Headlight Bulb
• SW Motech Center Stand
• Magnetic Oil Drain Bolt
• Many recent maintenance and servicing items including the countershaft oil seal cover, but excluding the neutral sending unit modification, were also included. New battery, chain. The seller advised that it's using a 13t front and standard rear sprocket. The actual countershaft sprocket turned out to be 14 tooth. The deal included a new SunStar 14 tooth sprocket in its retail package. Not sure where the confusion is coming from. Seems like a fairly simple area.

The KBB and NADA pricing put this model year at around $3,500--$3,800 in a retail setting, but the additional accessories, most of which I intend to keep, move the value into the price I paid. So, I'm fairly satisfied with the price. 

Additional photos:

The seller said that the DR was running 13/42 final drive (stock is 15/42) and included a new SunStar 14 tooth sprocket in the deal. I pulled the sprocket cover when I got home and it was actually a 14 tooth countershaft sprocket. The rear was 42 tooth. 

The bike has a fresh Shinko E-804 front and 75% worn E-805 on the rear. Generally, a used motorcycle with fresh tires is a good indicator in a private sale (i.e. seller wouldn't go to the expense and effort of tire swap if the bike has problems). 

The seller said he was not the first owner, but he did state that he rode the motorcycle to California. When I initially looked at the title, I looked only for the indications of it not being a clean title. However, I subsequently noted that the title date was 12/3/2020 and the mileage was 15,472 on the transfer date. That indicates that the seller added only 894 miles to the odometer; not exactly enough miles for a trip to California.

Well, all that aside...

The first serious ride will be the two-day Fall TransFlorida Adventure Rally that kicks off in Palatka, Florida on November 18. That'll be the real test for this old Bush Pig.

Updates:

This is a good example of why you should go over your pre-owned motorcycle with a fine toothed comb. All the maintenance that the seller said had been done, but someone missed the badly deteriorated air filter. This filter was devoid of oil, rotted and brittle.

Also, the airbox cover is missing. Given that the four screws that hold it in place are still in place, I'm going to assume that leaving the cover off was an (unnecessary) attempt to increase air flow into the airbox. That is a bad mod for Florida where are air quality is so bad and full of particulate. I once had a warranty claim on a Yamaha TW200 rejected because of particulate matter in the oil ... or maybe they were just being pricks.

Tracer 900 Throttle Bodies and Spark Plugs

2019 Yamaha Tracer 900 (Base Model) 

I just completed the second check of my throttle bodies sync, using my Digi Sync Vacuum Manometer (See July 2020 Original Post), and spark plug replacement. I'm performing this maintenance at 6,000 miles, which is 2,000 miles short of the intervals, because I'm launching on a trip that will extend well beyond the interval threshold. 

I have some video on this maintenance that Tracer owners may find useful.

Not to spoil it, but the throttle bodies were in reasonable sync at this 6,000 milestone as was the case during the first synch check.

Super Sherpa Fork Spring Rates

Details and dimensions on the front suspension components on my North American Model Year 2002 Kawasaki KL250 (Super Sherpa).

Fork Details and Dimensions:

• Front Travel - 9.1" (230 mm)
• Fork Type - Dampening Rod
• Inner Fork Tube Diameter - 1.42" (36 mm)
• Fork Air Pressure - Atmospheric +/- 0 psi
• Fork Oil - 10w, 10.14 oz each per change, 11.93 oz each per disassembly
• Fork Preload Adjustment - None
• Fork Compression Dampening - None
• Fork Rebound Dampening - None
• Spring Length - 573 mm (Service Limit 566 mm)
• Spring Length, My 2002 Model Year, 7,000 miles - 22.5" (571 mm)
• Spring Outer Diameter - 28 mm
• Spring Inner Diameter - 24 mm
• Spring Thickness/Gauge - 4 mm
• Spring Number of Coils- 43
• Spring Rate - Unknown

I am currently running 1 inch spacers on the front forks to compensate for the lack of preload adjustment. 

I recently replaced the seals and wipers with an All Balls Kit P/N No. 56-120. At that time, and after several hundred miles, I replaced the fork oil with Maxima 20w Fork Oil. I had been running a 10w mineral oil. 

St Johns River Loop

I started Florida Motorcycle Destinations, a motoblog of Florida-based motorcycle loops, last Summer when the pandemic had us all pretty well stuck-in-place. The idea for the motoblog arose from discussions on the Long Distance Riding Group and was ultimately designed as a resource of ride opportunities for moto-tourists vising our state for Bikeweek, BiketoberFest and all else that draws visitors to the Sunshine State.

Last week, I hit a milestone.

With the addition of the St. Johns River Loop, Florida Motorcycle Destinations surpassed 2,000 miles of riding opportunities, excluding Interstate Connectors. 

The St. Johns River Loop circumnavigates the St. Johns River between Palatka and Jacksonville. The loop is 131 miles; about 3 hours of saddle time.

I have a couple additional ride loops on the drawing board. Let's shoot for 2,500 miles!

Gone (Motorcycle) Fishing!

Eagle Claw 5' 6" PK555SP Telescopic Fishing Pole = $25

Shimano Sienna 4000FD Spinning Reel = $35

Plano Synergy Tackle Bag = $25

Waders = $10

Stumbling on a new fishing hole while out riding my motorcycle = PRICELESS!

Super Sherpa Fork Seals

The fork seals on my nearly 20 year old, 2002 Kawasaki KL-250 Super Sherpa began weeping fluid about 1,300 miles following it's purchase in January 2021; total miles are at 7,000. I suspect that the leak is the result from a combination of age and the additional compression strapping it on my Black Widow receiver carrier.

It's been a long time since I used a hitch carrier and seem to have forgotten that the rear should be the end with the strong torque.

Anyway, I came home following completion of the rough and rocky Smokey Mountain 500 and the equally rough and rocky Hooch Dual Sport Rally in GA, TN and NC last month with a long list of "things" that I wanted to do with the Sherpa; mods, some repair, some maintenance. The fork seals were already on the list.

I purchased the All Balls replacement seals and wipers from RMATV for under $25. The OEM replacement parts were over $60 and All Balls is a well respected aftermarket brand name. Given that I consider the Super Sherpa is "budget" equipment, I went with the low cost option.

Although I previously owned a 2009 model year Super Sherpa, I had no experience replacing it's fork seals from either model year. However, I do own a Service Manual that covers the process, which I followed subject to the following.

The Service Manual indicates needs for special tools. One to hold the inner cylinder in place for extraction of the lower retaining bolt and one for pressing the fork seal into place. I do not have those special tools, nor did I need them.

Lower Retaining Bolt

In general, the lower retaining bolt connects to the fork cylinder that is inside the inner fork tube and holds the inner fork tube securely inside the fork bucket (see diagram from Service Manual below). I was able to remove the lower retaining bolt with an 8mm allen bit adapted on my air impact driver at a low-torque setting while exerting outward pressure on the inner fork tube with one hand.

Once the retaining bolt was removed using the 8mm allen bit, there was a cir-clip that holds the fork seal and fork wiper in place that required removal with a flat screw driver. At that point, the inner fork tube (with the Fork Cylinder inside) could be pulled out of the Fork Bucket; a couple hard pulls are in order and the seal and wiper will come out along with the inner fork tube as shown in the photo below. The old seals and wipers were slid off the inner fork tube and the new seals and wipers were slid on, awaiting re-installation of the inner fork tube in the bucket and their proper setting.

Fork Seal Press

The inner fork tube with the new seal and wiper must be (1) reassembled with the bucket and (2) the fork seal and wiper must be pressed into the groove in the bucket head. Once in place, the aforementioned cir-clip can be reinstalled.

(1) The retaining bolt should not be replaced with the air impact hammer. Rather, it is extremely important to reinstall the retaining bolt at the proper torque setting, which is 20 ft/lb. Over torquing the bolt could result in problems including the inability to remove the retaining bolt next time the seals need replacement or other servicing of the fork is necessary. Use a torque wrench. I found that the cylinder didn't spin when torquing in the retainer bolt.

(2) The service manual calls out use of a special too to press the seal in place. I did not have such tool.

The seal and wipers are soft rubber and can be ripped or otherwise damaged. The special tool is designed to avoid damage as it exerts a flat consistent pressure around the seal and then the wiper. Without the tool, the seal and wiper can be carefully pressed into place with other flat surfaced tools ... a screw driver or tool with sharp surfaces are not tools to be used. It's simply selecting the right tool and then exercising care and patience that will get the seal seated. 

Once the seal and wipers are seated, the cir-clip was pressed back into place in the rim of the fork bucket.

As a general observation, I would like to add that I have been changing fork seals for decades and the design of the Super Sherpa makes seal replacement the easiest coming out and the easiest going in, certainly that I've experienced.

Fork Oil

I suppose fork oil could be saved and reused if it remains in good condition. However, it's usually more appropriate to change the fork oil when the fork is disassembled. In my case, the fork oil looked really bad after it's replacement a mere 1,300 mile ago when I purchased the bike. It had actually acquired that gray that motor oil gets when it's been used too much. I suspect that the prior fresh oil change had a cleaning affect.

The specified fork oil for the Super Sherpa is a Kayaba 10w (a fork-specific OE product) or SAE 10w-20. I used SAE 10w-20 for the change upon purchase in January. With the experience of having just completed three dual sport rallies, I decided to move to a slightly thicker, "dedicated" fork oil; specifically Maxima 20. 

The thicker oil should increase the otherwise very minimal dampening affect of the Sherpa's forks, but I'll have to get some time on the trails to see if that's the right direction .... or far enough.

Fork Oil Volume:

The fork oil volume differs between regular changes and full disassembly.

• Regular fork oil changes, specified for every two years, 10.14 ounces/300 ml.
• Full disassembly, as was required for the seal replacements, 11.93 ounces/353 ml.

Fork Oil Level:

Generally, fork oil level check is a periodic maintenance item with a specified interval of 7,500 miles. While the service manual calls out a fork oil level check when the fork oil is changed, I don't necessarily see the need.

When having disassembled the fork, such as the seal change, all oil is removed. As noted above, the manufacturer specifies a volume of oil (11.93 ounces or 353 ml) to refill the fork.  Since 353 ml is the specified volume, I would expect that volume of oil to produce the specified level, which for the North American Sherpa is 147mm +/- 2mm. In other words, during disassembly, the specifications for fork oil volume and fork oil level are, in fact, measurements of the same thing.

Fork oil level check, in my view, is more akin to checking your motor oil; sometimes we may need to add some, most of the time we don't.

Irrespective, following is an excerpt from the Service Manual on the Fork Oil Level Check. Note that a special tool is suggested. Similar to the special tools suggested for fork disassembly and seal/wiper installation, there are work-arounds for the special oil level test tool, as well. 

The Special Tool for fork oil level test is actually a common and widely available tool. Cycle Gear has such a tool for $22. The OEM tool is $80. However, the Special Tool is the quintessential definition of a Rube Goldberg. 

A family member once gave me one as a gift; never used it. 

Essentially, the design of these tools is actually a syringe that will "extract fork" oil down to a specified measurement from the tube's rim; about 5.75 inches for the fully compressed fork for the Sherpa. It's just a check though! All we need is a simple measurement for the level check, a dipstick can be made for use out of any clean straight object that fits in the tube's inner diameter of 1.4" (36mm) and is longer than the specified level measure of 5.75 inches.

Just like the motor oil check, add fork oil as needed. Removal of oil during a check, which the special tool is designed for, is rare. Why?

Well, if the proper amounts of fork oil have been used for routine changes and disassemblies, where did the excess oil above specified levels/volumes come from? An overfill, both intentional and unintentional, is the only answer. And an intentional overfill is the basis upon which the special fork oil level tool works; in short, overfill the tube and extract the oil down to the proper level using the syringe.  

If I may make a suggestion, just use correct amount of oil during changes, disassemblies and checks, and you won't need the $20-$80 tool.