Session 54: Front wheel stumble
Midweek I stopped by the cave after work to complete the addition of new rubber on the RVF.
I double checked the wheel arrow was pointed in the direction of rotation then fitted the lightly greased longer spacer against the right wheel bearing and the shorter spacer on the left. For the most part they styed put when I slid the wheel between the forks. Maybe 1/2" of clearance. I then inserted the greased axle thru the left fork, wheel and out the farside right fork. A few hits gentle taps with a dead blow mallet until the axle slid to a stop. :thumbup
Next, hand tightened axle nut followed by a torque wrench fitted with a 7/8" socket (I’m finding my Kirkland socket is limited to the smaller metric sizes). Click went the wrench. Click again to double check. Wheel check - rotates easily and no lateral movement. Done. :thumbup:thumbup
Next tightened the 4 fork clamping bolts to spec. Four clicks and a recheck. Done. So far so good. :thumbup:thumbup:thumbup
Brake calipers are last. I split the left caliper pads over the brake disc and wedged it into position. With tapped caliper holes aligned to the fork thru holes the I hand tightened the two M8x25 flanged bolts. Repeated with the right caliper. :thumbup:thumbup:thumbup:thumbup
Torque wrench dialed to 31Nm (24 ft-lbs) and 12mm socket onto the bolts, I tightened the left caliper's bolts. First 2 clicks and done. Double checking I tightened them again. A tiny bit of additional movement but both clicked mostly right away. Moved to the right side caliper and repeated. The wrench clicked fine on first bolt. The second bolt didn't feel as solid and seemed to turn further than expected but finally clicked. Hmm. Going back to the 1st bolt I torqued and got maybe an 1/8th turn before I got the confirming click. Not the expected immediate click. Moving to double check the 2nd it turned, and turned and turned maybe 1/2 a revolution before it clicked again. Uh oh, were the caliper threads puling out? The tactile feedback was not reassuring. :thumbdown
In denial, I checked again - getting a further half turn. Something was not right. I undid both bolts and inspected. No thread chips or metal was visible. I pulled the caliper off and saw intact internal threads. What gives? :thumbdown:thumbdown
Looking more closely at the bolts I saw that the threads looked malformed. Yup, the bolts were clearly yielding and necked down. I tried to jigsaw the two bolts' threads against each other and they wouldn't puzzle together. They were toast - tightened beyond their elastic limits and permanently stretched. The culprit could be a non-calibrated torque wrench or perhaps the a previous mechanic’s doing. If I get motivated I will verify the torque wrench with weights and a bench vise. :rolleyes
Lucky to have found this out in the garage than on the road. Would a hired mechanic have caught this or clicked and moved on? The other silver lining is fasteners are a much easier fix than Helicoils. :thumbup
Bat cave secured, I scurried over to OSH, rummaged thru the fastener bins and found potential replacements: M8 (8mm diameter across the threads), 1.25mm pitch (distance from thread crest-to-crest. BTW considered "coarse" for an M8), and 25mm in length. The simpler designation is "M8 x 25mm, coarse". These were clear zinc plated like the OEM ones.
The next descriptor is grade. Bolts come in different tensile strengths for different applications. JIS Japanese Industry Standard has Grade 10.9 JIS. $1.56 each. I learned there is a higher 12.9 grade but OSH only had 10.9 so I bought them. Anyone know if grade 10.9 proper? :|
Last but not least, as far as parts go turn signals arrived from 4 week trip from China. $8 shipped. :thumbup I consolidated a Tyga order with Anthony to a get a light weight front fairing stay. Mine is a bit buggered.
