Sunday, April 22, 2012

WR250 rear shock rebuild

From the factory, the rear shock on the WR is similar to that found on the DR.  In other words, the valving sucks.  I thought  about removing the shock over the winter and sending it off to a professional suspension shop to have it rebuilt/revalved, but I just never got around to it.

Recently, I found someone selling a gently used shock from a 2010 WR250X which had 3 or 4 thousand miles on it. I bought it for $100 and the seller just happened to live in New Jersey, not far from a well known suspension shop called WER Suspension. A few people from the WR250 forum have had lots of good things to say about these guys and the great work they do rebuilding suspension for the WR.

So, the seller agreed to drop off the used shock at WER instead of shipping it to me. I called WER and spoke with Drew, explaining my plan for the used shock, and my request to have them ship it to me once they've rebuilt it. They called me a few days later to confirm the work was done, and to get my credit card number for the work. They billed me for $230 which included all the revalving work and the shipping charges.

Here is it, ready to be installed in the bike.  I may not get around to it for a couple of weeks, or maybe even a month or so, as I'll be away soon on a business trip.  I'll report back once I get it installed, and after I've had a chance to ride on it.

Only the shock's internals have been upgraded. Drew advised me to keep the OEM spring (rated for 7.7 Kg/mm) and try the upgraded shock with just the new valving work. He suggested that with the proper valving, the stock spring should be just fine for riders up to 200 lbs.  Since I'm right at the limit, I considered going up to an 8.3 Kg/mm spring, but he reminded me that I could always change the spring later if I didn't like it. 

Thursday, April 19, 2012

WR250X / WR250R oil and filter change

Shortly before I bought the WR, the previous owner said that the Amzoil sythetic oil and OEM filter had only been in the bike for a couple of rides, maybe a few hundred miles.  But since then, I've put about 2,000 Kms on the bike, so I figured it was time for fresh oil.

While I'm sure it's top quality stuff, I'm too cheap to shell out $30 or more dollars for 2 litres of Amzoil. Instead, I'm a Rotella man -- prefering to mix old fashioned dino oil with sytnthetic (my own synthetic blend, if you will).  At Wal-Mart, I recently picked up a large 9.5 L jug of 15W40 conventional oil for $32. I also picked up a 5 L jug of 5W40 synthetic for $37.  Between the DR and the WR, this should be enough for a few oil changes.

Also, a full oil change isn't complete without a new filter. Yamaha sells the OEM version for $15. What a rip off. Being a cheap bastard, I bought 10 (ten) aftermarket filters from RockyMountainATV when they were having a sale. $2.50 each ($25 for 10). 

First, park the bike on reasonably level ground. Place an oil drain pan under the engine. Use a 12mm socket to remove the drain bolt and let it drain. You can do it with the engine warm, as some might recommend because the oil will flow out better. But I prefer to do it when the engine is cold and has been sitting. This way, I am sure that all the oil is in the lowest part of the engine. Either way... it will still follow the laws of gravity.

While the oil is draining, use an 8mm socket to remove the 3 bolts that hold the oil filter cover in place. It will be a little messy here. It's a good idea to stuff an old rag between the engine case and the frame rail to prevent oil from running down the engine case and making a bigger mess than necessary. 

Check the condition of this O-ring

the old, dirty oil filter.

Check the condition of this small O-ring 
(located at 12 O'Clock, about 1/2 inch above the hole for the oil filter)
Pull the old filter and then use a clean rag to wipe the cover, the bolts, and the hole into which the filter sits. Be careful not to lose the large O-ring on the back side of the cover, nor the small O-ring that is found on the engine case. It's wise to inspect these while you're in there.

According to the service manual, you will need 1.3 Litres when performing an oil and filter change.

I poured in about 1.2 Litres and decided to check the window to see the oil level (it's easier to add 100 extra mL if you need to, than it is to drain 100 mL).

Then I replaced the filler cap, and started the engine for a minute. Even went for a quick ride to the end of the street and back. Then turn off the engine, let it sit for a minute, and check the oil level again. I ended up adding the remaining 100 mL of oil, so in the end, I used exactly as the book prescribed: 1.3 Litres (or 1,300 mL).

DO NOT OVERFILL. If you do, remove the drain plug for a second or two and let some drain out. Overfilling the crankcase can result in blowing the seal behind the gear shifter, if you're lucky. It could also be much worse.