Clutch pulled and problem discovered

I borrowed a clutch spring compression tool from a local indie and opened up the clutch. I found a disintegrated spring plate in the middle of the clutch pack and broken rivets all over the place. Also, the neighboring friction plates were eaten away by the broken rivets. Also, a groove has been worn in the clutch basket by the springs leaves from the spring plate that were no longer held in place by rivets. Argh! Terrible design. Terrible failure mode. Fortunately, I did not ride the bike too much after the failure occurred. The groove is not bad and and the burrs on splines where  the groove is can be filed down, I hope. I have decided to eliminate the spring plate from my clutch by replacing it with a St-F-St combination (St=steel plate, F=friction plate). I measured the thickness of the spring plate and St-F-St stack and they are within 0.005" of each other, so I think I am good to go. I ordered parts from LSHD1.com (Lake Shore HD) and am waiting now. Also ordered a Helicoil kit to repair the thread on the primary cover where the clutch cable screws in. That's been on my list for a while, but I did not want to pull the primary cover. Now I had to pull it, so...

Pictures:

Clutch spring compression tool doing its job by compressing my clutch spring

Disintegrated spring plate

Friction plate damaged by failed rivets

Primary cover off and clutch out

Another view of failed spring plate

Clutch out of the basket

Groove worn by failed spring plate

Another shot of the groove and burrs on the splines

Clutch problems

Went for a ride the other day and realized that my clutch is feeling funny. It seems to drag. When in gear and clutch lever pulled in all the way the bike tries to move a little (no full clutch disengagement), neutral is very hard to find, shifting is very difficult. After some miles on the road the problem sometimes goes away completely and clutch behaves normally again. Easy shifts, neutral is right there where it should be and easy to get to. I tried adjusting the clutch (under the derby cover) to no avail. I thought I had my primary case over-filled, so I drained a bit of fluid. No joy. So I did some research and realized that it's a common problem and lots of Sportster clutches go after 30K miles or even way before that. My bike now has around 43K miles. Apparently, the Sportster clutch consists of 8 friction plates, 6 steel plates and one plate that is called a "spring plate", which is two plates riveted together with brass rivets that have spring leaves pushing outwards. This plate is not the main clutch spring, but is there right in the center of the clutch stack to take up some slack between the plates when the clutch is disengaged. Apparently, the brass rivets eventually fail and the two spring plates come apart and jam the clutch making it difficult to disengage. Also, they can do some damage tot he clutch shell and neighboring friction disks. The configuration, according to my shop manual is this:

F-St-F-St-F-St-F-SP-F-St-F-St-F-St-F

where

F=friction plate
St=steel plate
SP=spring plate

I stopped riding the bike now until I've sorted it out. I need to pull the clutch pack to have a look. For this I need a clutch spring compression tool. Argh! If the spring plate is in deed the problem, the solution seems to be to either replace it with a new part ($40) or eliminate it from the clutch pack by replacing it with two steel plates and a friction plate, which according to the people who've done it, makes up the same stack height (very important for proper clutch operation). So the new configuration will look like this:

F-St-F-St-F-St-F- St-F-St -F-St-F-St-F-St-F

This increases friction surface area making the clutch grabbier (good? bad? doesn't matter? takes getting used) and apparently no other ill effect is caused by this modification. I can also get a whole new aftermarket clutch pack with spring plate elimination already implemented. This is around $150 or so. I will consider my options once I know exactly what the problem is.

My rear brake is like new again! Here's how I did it.

As my previous post says, I rebuilt the rear master cylinder a few weeks ago. The rebuild went fine, but the pedal feel was still soft and the pedal travel was long. The brake felt strong enough to be serviceable, but definitely not fully there. On advice of a fellow Sportster owner I tried the following. I gently pushed the caliper piston all the way back by using a large screw driver between the pad and the rotor. It is not hard to do if the caliper is in good shape. Does not take much force. I then jammed the pad with the screw driver so that the piston would stay pushed in when I apply brake pressure. I then proceeded to bleed the brake the old fashioned way:

1. Open the bleeder
2. Gently push the brake pedal
3. Close the bleeder
4. Release the brake pedal

I repeated the above steps three times, then added some brake fluid to the reservoir and pumped the pedal with the bleeder closed a few times. The pedal travel became mush shorter and the feel became much firmer. I then removed the screw driver from between the brake pad and the rotor and gently pumped the pedal until the piston came out to meet the rotor. The pedal feel and travel remained good. Went for a ride and was amazed at how much better the brake felt. I would say it's 100% back to normal now.

Rebuilding the Rear Master Cylinder

I have received the rebuild kit for the rear master cylinder (HD P/N 42810-04B) a few days ago. The kit contained the following items:

• new primary seal (cup)
• new piston
• new piston (secondary) seal
• new piston return spring
• new C-clip for the pushrod retaining washer
• new pushrod rubber boot
• new spring pin
• a pouch of grease
• a pouch of brake assembly oil
• a set of instructions on how to use the kit

Upon examination of old vs. new parts I immediately saw a defect in the old piston return spring that would explain the primary cup failure. If you look at the pictures, the new spring is on the left and the old is on the right. The new spring has a very flat surface at the top end. This is the end that is in direct contact with the primary cup. The little nub on the cup fits into the hole in the spring and the piston pushes the whole thing from the other side of the cup inside the bore. Look at the old spring's mating surface. It has high points that will create uneven pressure on the rubber cup and eventually wear cracks in the rubber, which is exactly the mode of failure here.

I am not sure if something happened to the spring to create this uneven surface or it was like that from the factory, but I can definitely see how this will cause problems with longevity of these cups. Every rear MC failure (talking rubber-mount here) I have seen out int he Sportster community had this cup tearing in a very similar way. It may be that excessive pumping during the initial bleed of the system compresses the spring to the solid state (coils binding) and then the pressure from the piston collapses the thin sheet metal of the flat mating surface around the spring wire underneath. I am just guessing here. The only way to know is to take my MC apart in a few thousand miles and see what the insides look like. I may do this in the future, but for now I am just trying to get my bike back on the road.

Rear Master Cylinder Failed!

Well, it happened. The rear master cylinder on  my Sportster failed at 41,600 miles. It really wasn't all right since the rear pad change at 30,000 miles. The rear brake has been weak and required a bit pf pumping once a day to get the pedal to not sink too far down. Once pumped up it would stay up for a relatively long time (days). The rear brake was not totally mushy, but it was not all that strong. I could still lock up the wheel, but with more effort than I thought was necessary. Anyway, since the brake was sort of serviceable, I left it alone until an opportune moment to deal with it. Well, that moment arrived a few days ago when I removed the rear wheel for a tire change. I get my tires online at Motorcycle Superstore which has the best prices on tires for my bike, BTW. I then remove the wheel assembly and take it to a good shop to mount the new tire. So, while the wheel was off the bike I decided to bleed the rear brake and get rid of that funkiness.I hooked up my MityVac and proceeded to vacuum bleed the brake via the bleeding screw on the caliper, which I removed from the swing arm and hung up such that the bleeder screw was the highest point in the system. This causes air bubbles to collect at the bleeder and not in that arch the brake line makes when the caliper is on the swing arm. If you own a rubber mounted Sportster you know what I mean. Anyway, after bleeding I had NO REAR BRAKE AT ALL! WTF?! Well, I read up on various forums, but mostly here that this is a rather common issue. After changing the pads and pushing the rear caliper cylinder back to accommodate the new pads many, many, MANY people observe the failure I had. Even the pictures look the same as what I found when I disassembled my rear master cylinder. I have ordered a rebuild kit and will rebuild this thing and see how things go.

Cold ride yesterday

I went for a ride yesterday and damn near froze my butt off! It was way colder than I expected. I cut the ride short and made myself a hot beverage when I got home. Brrrr! Where is that spring?

Great ride today

As I planned yesterday, I did go on a ride today. I started by giving the bike its Spring Bath (it usually gets very few baths, so this is special :) ). I then rode over to North Star where my older son Jonah does most of his home schooling. The staff there was interviewing parents of teens who go there for a video clip to put on their web site. I did my interview and just as I finished the interview my riding buddy Bill pulled up to the building (as per prior arrangement). We left Hadley around 1 pm and headed over the Rt. 9 bridge to Northampton and from there north towards Deerfield on Rt. 5 and 10. From Deerfield we took 116 north to Ashfield, which is the best piece of motorcycling road around here and is probably a mini Dragon. From Ashfield we took 112 north to Vermont border and in Vermont we took Rt. 100 north to Rt. 9 east, which is another amazing road with a great overlook of the valley to the south and east. Rt. 9 east leads straight to Brattleboro, which was our tentative coffee break stop. We had our respective beverages in a great little coffee shop (I had tea, Bill had coffee) and headed out of town on Rt. 5 over the Connecticut River to New Hampshire, where the same road becomes Rt. 119. We followed this rode along the river to Hinsdale, NH where it meets Rt. 63. We took Rt. 63 south (again along Connecticut River) all the way to Massachusetts. By the time I got home around 6 pm I had 140 miles on my trip odometer covering 3 New England states. That's one of my favorite loops around here. But not the only one.