Sunday, February 12, 2017

14T vs. 13T countersprocket on WR250R (updated)

Stock gearing is 13/43 on the WR250R. I've been running 13/47 with good results, and thought that bumping to 14/48 would give better highway performance while leaving the easy option to swap to a 13/48 for dirt use without requiring much chain adjustment.

Unfortunately, a 14T with chain leaves uncomfortably low clearance on the bike if also running with a case saver like the one I made.

Here are pics of a new Dirt Tricks 14T compared to a worn 13T. I'll be sticking with 13T and have opted for a 45T sprocket on the wheel to test with some Mitas E-07 tires that I'll be testing this year.

Here's view of the 13T with 48T rear sprocket with new chain mounted to show clearances. It's a bit tighter on the rear than I'd prefer, and I expect the guide will show accelerated wear. May need to look for aftermarket sliders and guides made from harder material and with more clearance. 

Note: Yes, I had a brain fart and accidentally installed the quick link clip backwards (closed end should face chain direction). I fixed it after taking this pic.  

New carbon road wheels

As part of my Rugged Wheels packages I'm offering two carbon wheel sets.

The first is a 38mm rim with DT Swiss 350 disc brake hub (centre lock or ISIS), laced with DT Competition straight-pull spokes and ProLock nipples. This is aimed at cyclocross or gravel riding.

The second wheel set is a 60mm deep rim with a DT Swiss 240 hub (Shimano or SRAM), laced with bladed spokes and ProLock nipples. I'm still trying to work out a reliable supply of spokes but my goal is to offer DT Aero Comp in straight-pull. This is a rim-brake wheel aimed at TT or regular road use. The braking surface is basalt and the wheel includes special pads for either Shimano or Campagnolo brakes.

Both wheel sets are built tubeless-ready.

Optional end caps are available to convert between thru-axle and QR, and DT Swiss skewers are available as well.

For more information and pricing, contact your local bike shop or Rebec & Kroes or Almonte Bicycle Works.

29+ wheels for your fat bike

Bike shops I've spoken with report that if someone's planning on having just one mountain bike, increasingly it's a fat bike. In Eastern Ontario where I live, this is definitely a trend because it lets you squeeze more fun out of winters that are becoming more unpredictable for freeze/thaw and snow.

Fat tires are great in snow and other soft conditions, but are overkill for summer riding. One solution is to get a second set of wheels with a narrow rim that let you run 3" tires. This combo can shave a few pounds off your wheels compared to a standard fat setup. More importantly, reducing the rotating weight improves handling and acceleration, making a ponderous fat bike feel almost sprightly on summer trails.

This is a wheel set I'm offering as a solution. Hubs are the excellent DT Swiss Big Ride, running 150mm x 15mm thru-axle in front and 190mm x 12mm thru-axle in the rear. The rear hub is easily converted to 197 mm wide by swapping optional end caps, and both Shimano and SRAM XD freehubs are available. Note that in the picture the front wheel shows a centre-lock disc brake mount and the rear an ISIS (6-bolt) mount. ISIS mount will be standard on both.

Rims are DT Swiss XM481, which is a robust yet lightweight option for all-mountain use. Spokes are DT Competition butted with ProLock aluminum nipples. Wheels are tubeless-ready.

For more information and pricing, contact your local bike shop, e.g. Rebec & Kroes or Almonte Bicycle Works.

Custom bicycle spokes

One of the latest additions to my shop is a gorgeous Morizumi spoke machine. This elegantly designed and made tool allows me to cut and thread custom spoke lengths, an important capability when building wheels as so many different lengths are needed. As part of this toolset I also acquired a Mitutoyo digital tensiometer which has demonstrated excellent measurement consistency in wheel building.

Cut and thread quality with the Morizumi is actually superior to that on OEM spokes I've inspected, although there's a bit of an art to set up and use the tool. 

Here's a sample of spokes threaded while experimenting with different techniques. The curvature is optical distortion from the jeweler's loupe positioned in front of my cell phone lens--not an actual bend in the spoke. 

Here's an almost perfect thread in a 2.0 mm straight-gauge, stainless steel DT Swiss spoke. The Morizumi applies about 9-10 mm of thread. 

And here's a sample board I made up while trying different threading techniques and set-ups. Once it's dialed, each spoke comes out perfect.

As part of my Rugged Wheels business I offer custom spoke cutting services. Unless they are obviously damaged, most spokes can be safely re-used as-is, or cut down and threaded for a different application. This is certainly cheaper (and faster) than ordering new spokes only to find they may be the wrong size!

Unfortunately there isn't a comparable machine for motorcycle spokes. However, I do have access to the full catalogue of Bulldog Spokes from Central Wheel Components in the UK. These are among the best in the industry and what I use to build moto wheels.

WR250R fuel pump replacement and new IMS tank

The WR250R is known to have a flaky fuel pump in some 2008 and earlier models. Mine's a 2009, and while I haven't had a problem with my fuel pump, I wanted to understand the issue better and do some preventative maintenance at the same time as upgrading my fuel tank.

There are many good posts online about how to remove the tank and fuel pump assembly. Rather than repeat that information, I'll just add some tips and clarify some points that I would've found helpful along the way.

Removing the old fuel pump
The top and bottom parts of the fuel pump assembly are snapped together with three moulded tabs. It is entirely possible to pry apart the assembly and ease out the old pump in a few minutes without damaging anything if you follow these tips:
  • When disconnecting the fuel line from the tank, slide the orange plastic cover out from the connector to reveal the blue "buttons" on both sides of the connector. Squeeze both buttons while sliding off the connector. It helps to push the connector all the way on first, squeeze, then pull straight off. If you squeeze while the connector is near the end of the spigot, the locking mechanism can get caught and not release. 
  • Disconnect the wires and fuel level gauge to give yourself more freedom to work. Note there are tiny spring clips holding the spade connectors in place--don't try to yank off the connectors without pushing on the spring! You need to remove the top heat-shrink from the blue wire to access the spring and disconnect the fuel pump.
  • Use a sharp knife to shave off the high points of the tabs, so you don't need to pry as much to slide them under the retainers.
  • Pry each tab one at a time using picks, and insert a washer to keep it from snapping back together while you work on the other tabs.
  • Do not disconnect the black fuel hose. It's a stiff material, but you can gently bend it back enough to slide out the pump.
  • Do not try to detach the fuel filter. The pump will slide out fine with it attached.
Choosing a new fuel pump
Yamaha sells the fuel pump only as part of the complete assembly you unbolt from the bottom of the tank. It costs about US$350. However, unless you've somehow broken the plastic, there's no need to replace this whole assembly and instead, you can just replace the fuel pump mounted inside.

Some searching of forum discussions led me to this Kemso kit from eBay for about CAD$40.

The pump itself is made in Japan and appears to be well made and almost identical to the OEM pump. The kit includes three versions of the intake filter; one matches the WR250R original. 

Original fuel pump is on the left. The filter installs easily with a ring washer that I pressed on with a small socket.

There's a small o-ring inside the top plastic frame that I figured (after assembling and disassembling the plastic twice) is more easily installed by mounting it on the fuel pump first. 

Here's the new pump in place, ready to click the frame back together. Don't forget to install a new piece of heat-shrink tubing over the top connector on the blue wire. 

Sharp eyes will notice that the pump seal around the bottom is a thick o-ring, not the original rubber seal. This is what came with the IMS 3 gallon tank I ordered.

Installing the IMS tank

Having looked at different tank options, I concluded that the extra gallon of the IMS 3.0 over the stock Yamaha tank would eliminate my frequent need to refuel from my 1 gallon RotoPax. In theory the IMS should give me about 250km of range, which is plenty for my current needs. Plus I can still carry an extra gallon (3.8L) in the RotoPax, for almost 100km of safety margin. 

The "clear" tank was a little cheaper than black, and I might as well benefit from being able to see how much fuel is really left. Aesthetically though it's bag-on-head quality--as you'll see in a moment. Also, the cap vent line is just a hose so something like this would be nicer.

Here's the fuel pump assembly bolted on with the o-ring provided by IMS. The o-ring is a really stiff material that deformed the plastic unevenly when the pump base was tightened. I didn't like the reliability implications of this stress, so I decided to use the original seal which reduced distortion and hasn't leaked so far just sitting in my shop.  

With OEM tank seal:

And here's the assembly all tucked in and cozy in its little chamber of horrors, as seen through the filler hole:

The original tank (right) is covered with foam reflective insulation. I figured it would be a good idea to similarly protect the bottom of the plastic tank. The Yamaha insulation was remarkably similar to some inexpensive pipe wrap I bought at Home Depot for another project. It stuck to the IMS plastic no problem.

Installing the IMS tank revealed fit issues on the left side (the right side fit fine). No amount of persuasion and trickery could eliminate this unsightly gap between the panels. And it wasn't because of the insulation I had added; same problem without! 

In an age of 3D scanning and CAD, I think this fit issue is unacceptable and a major strike against the IMS 3.0 gallon tank. However, I need the additional tank volume so I decided to try to make the best of the situation. That entailed some ghetto masking with a rubberized tape to make the gaps less obvious. Really embarrassing workmanship here, but I couldn't see an alternate approach without heating, cutting, or bending plastic--which introduces a whole bunch more problems. I'm not the only one to complain about IMS fit; I just thought it would've been fixed by now. Caveat emptor!

Right side fits fine, although there's a noticeable gap along the seat bottom as well. IMS really needs to fix this, but probably won't because the market is diminishing.

Update September 21, 2017

Having ridden this upgrade hard for a season now, all seems to work fine. No hiccups with the pump performance, and no leaks on the tank using the original seal (not the IMS included seal). The unsightly gap between the tank and shrouds still bugs me, but the relief of having 250km range in the tank is well worth the tradeoff.