Thursday, Jul 16 2020 [5,307 miles]
I thought I’d buy a complete oil filter set, one that includes the drain plugs with screen. The goal is to have some on hand. Murphy says that the likelyhood of needing a replacement drain plug w/screen is much higher you don’t have a replacement ready. In the future I hope I’ll only need to buy the oil filter.
As long as I was buying I added a replacement front sprocket to my order. This one has 15 teeth. Stock is 16 teeth. It will change my sprocket ratio from 2.8125 to 3.0, a 6.6% increase. I can live with that on the top end to get a little more at the bottom end. If I don’t like it I can always put the stock sprocket back on the bike. Tomorrow I’ll install the sprocket and see how I like it.
Friday, Jul 17 2020 [5,314 miles]
The bike lives on the lift. I used the rear stand to lift the tire off of the lift and jacked the lift up to a comfortable working height. With that done I removed the shift linkage bell crank to get at all the screws holding the sprocket cover. That was followed by a few minutes of scraping crap out of the inside of the cover.
There is a safety washer bent up to hold the sprocket nut in place. With the safety washer bent more or less flat I broke out the impact wrench to break the nut free. There isn’t enough slack in the chain to remove the sprocket after removing the nut and washer. I loosened the rear axle and moved the chain adjusters forward on both sides of the bike. That gave me enough room to remove the sprocket.
Before installing the new sprocket I spent a few minutes cleaning some of the grunge off of the engine case. I put the chain around the new sprocket and pulled it tight to give me enough room to slide the sprocket over the splined output shaft. With the sprocket in position I tightened the adjusters to take some of the slack out of the chain. I wanted to rotate the rear wheel and make sure everthing tracked well.
I torqued the sprocket nut to 100 Nm, but did not use Loctite on the nut. I didn’t see a need for using Loctite AND a bent safety washer. The safety washer goes over the slined output shaft. I didn’t guess right so a new portion of the washer was bent to match the flat in the nut. It probably doesn’t make any difference.
I did use Loctite on the three screws that hold the sprocket cover to the engine case. Ditto for the screw holding the bell crank to its shaft. There was a mark on the bell crank that I aligned with the notch on the shaft for proper positioning.
The last step was to adjust chain slack and torque the rear axle to 90 Nm. With that done I put tools away, put on some riding gear, and took the bike on a short test ride.
Excellent! On the freeway I’m crusing around 5300 – 5600 RPM. Not that much different from the 5000 – 5300 range with the stock sprocket. The big difference is when coming to a stop. I typically downshift as I slow down until I hit 2nd gear. As I approach the stop I pull in the clutch, shift to first, and use my brakes to come to a full stop all at the same time. With the stock sprocket I often found myself going too slow for second gear, causing the engine to buck a little bit before I was ready to shift to first. No longer. I’ve got just enough extra low end to keep the bike in 2nd until I’m ready to stop.