Monday, January 22, 2018

WR250R winter rebuilds

With the weather oscillating between -40 and +12C, and an ill-timed crash while fat-biking that led to a sore knee, it was finally time to inspect and repair my bike for the upcoming season. This year I'm planning an epic romp that starts in Ottawa, follows the Appalachians down to the Trans-American Trail, sneaks up the crest of the Rockies to Wyoming, and beelines back home via the South Dakota Badlands and part of the TCAT north of Sault Ste Marie. Both bike and rider both need to be in good shape for this journey. If you're interested in joining, drop me a line and check out the ADVRider thread.

The WRR has now accumulated about 27,000km of 50/50 dual sport riding. Last winter I tackled several minor mods to the bike, so I was curious to see how these "improvements" stood up after a relatively short but chronically wet and punishing season of 6,000 km of trail riding.


Removing the skid plate revealed some shortcomings with my latest anti-vibration strategy. It consisted of an adhesive asphalt matting to replace prior failed attempts to use a glued rubber sheet. The asphalt material had softened and flowed with engine heat, and allowed significant accumulations of rocks and other debris to become embedded and rub against the frame, especially in the contact area under the cradle.


Since the matting itself seemed to work well at preventing reflected noise, I decided to just carve out the worst areas of grit (and all in the contact areas), and cover the remaining material with thin adhesive aluminum foil.


This should prevent more crap from becoming embedded where it can touch the frame. In addition, I laid a thin bead of silicone weatherstripping along the areas contacting the engine cradle. This shouldn't collect grit and should provide a secure base to tighten the skid plate bolts. With the asphalt material, I discovered that the bolts loosened and eventually fell out as the material softened, despite using blue Loctite.

All that grit sandwiched between the skid plate and cradle caused some abrasion and superficial rust on the steel. Light sanding followed by 6 coats of primer and paint, combined with the above skid plate mods, should resist further corrosion.


Replacing the OEM gas tank with the larger IMS last year proved to be well worth the money. Being concerned about exposed plastic soaking up engine heat and potentially deforming or degrading, I decided to apply a foil-faced foam insulation as thermal protection. This resulted in a slightly tighter fit than ideal, and some spots where clearances were especially tight (like over the radiator main outlet, shown on the left of the photo below), rubbed and wore through the insulation. This type of friction isn't good, so I peeled off all the foam and replaced some areas with just foil tape. The tank now mounts a little more easily although the hideous gaps remain on the sides (a design flaw).


While the paint was drying I also decided to repair a cracked corner on my home-brew signal light bracket, which was needed to incorporate the tail-tidy kit I had installed. The first version was fabricated from three section cut and filed from 1/8" 6061 aluminum plate, the side pieces riveted on to the centerpiece using extruded aluminum angle brackets. One corner bracket got bent in a tip-over, also cracking the turn signal housing. While hot glue fixed the housing, the bracket needed to be replaced.



Rather than fabricate an entirely new set of parts, it was easier to drill out and replace the corner brackets with new parts made from stainless steel salvaged from the decorative front panel of an old dishwasher. (The dishwasher that has kept on giving and giving!) It's a springier assembly to allow more give. These were riveted to the centerpiece using beefier stainless rivets, and the side pieces were attached using stainless screws and nuts to facilitate removal if necessary. Otherwise, removing the taillights means disassembling the whole back end, which is a nuisance in a warm shop and not recommended at all on a trail.




With the swingarm off I also inspected and cleaned the pivot bearings and chain slider. The pivot bearings may need replacing before my TAT adventure. The slider showed even wear--indicating no chain tensioning issues--but I really don't like how it sits over the pivot bearing cover (the brass-colored part) and digs into the swingarm. The material is too flexible and allows grit to become trapped underneath, which then acts to grind down the swingarm. You should be aware of this issue so you can inspect the swingarm before it leads to failure.


As a temporary fix, I reapplied some JB Weld to fill the worn areas. A better solution would be to fill the worn area with metal, but that's not a feasible option for me. 




A proper fix would eliminate the rubbing caused by the slider design. A search of eBay indicated that TN Designworks finally offered an aftermarket, improved slider made from oil-impregnated hard plastic for the WRR, so I ordered one only to find that although I'd requested the right part, the vendor shipped me something that obviously wouldn't fit.

 
Searching the TN Designworks site led to more disappointment: they still don't--and are unlikely to--offer a slider for the WRR. So if anyone has a recommendation over the OEM Yamaha slider, please let me know.

A clutch inspection (very helpful using my own guide at this link!) showed virtually no wear since the last time I checked two seasons ago. At this rate I should get another 20,000km out of it before the friction plates need to be replaced.

Likewise for the front rotor: it has worn to only about 3.45mm thickness versus 3.5 mm stock and wear limit of 3.0 mm. No need to replace. However, the rear rotor wears faster in typical trail riding, so I replaced it last season.

New farkles arriving soon include Fastway Adventure footpegs from Gnarlyparts, and a Shorai LFX lithium-iron battery from Fortnine to replace the lead lump while benefiting from considerable weight loss and capacity gain. Also on the shopping list is (finally!) a new, lighter jacket (probably the Klim Carlsbad, to replace my heavy and leaky Olympia MotoQuest) and new armour (leaning towards a TekVest RallyMax tp replace my deteriorating Fox pressure suit).

2 comments:

  1. Hey, I enjoy your empirical and analytical approach to your bike and mods. In fact, I adopted your front/rear sprocket ratio. Keep it up.

    ReplyDelete