My initial plan was to send the cylinders and head to Hondaman over this past winter for top end work but there were too many other projects in the garage for me to get around to it, so I decided to ride the bike with the motor as is for this season, then get the top end work done next winter. Let's get her into riding condition and put some miles on her before that project begins.
Still there is lots to do to the 550. Parts began to arrive:
The parts to the right are for a buddy's 1986 Honda Fourtrax 250, most of the other bits are for the 550. New cables, stainless steel brake lines, new caliper piston and seal, master cylinder rebuild, clutch, fuel line, valve tappet covers (some of the old ones were cracked), rear shocks/springs as well as fork springs.
I noticed some clutch slippage at high throttle as well as some slow clutch engagement at times when upshifting, so new clutch and springs were ordered. I got the heavy duty spring set with 10% higher spring rate than OEM. That was a mistake, it's very hard to pull in the clutch now, so I have new OEM replacement springs on the way. Interestingly, there are 6 springs included in the EBC clutch spring set although the bike only requires 4 springs. I thought perhaps that I ordered the wrong set but after checking it is correct, in other bikes all 6 springs are used.
(note to self - next time be sure to put on the oil drain plug before filling the crankcase with oil)
I tackled the front brake work next, which went smoothly for the most part. It did take a very long time for all the little air bubbles to work themselves out of the system. After lots and lots of bleeding it is necessary to pump the brake handle over and over to force the last bits of air out of the system. I read lots of posts on SOHC/4 about the right way to do this and I think I tried them all. But in the end it just took an hour or so (at least it seemed that long) to coax the tiny air bubbles out of the system. On other bikes I've done this a big air bubble would be forced out after a few pumps. On this bike it was a seemingly endless stream of very tiny little bubbles. But in the end the brake lever firmed up and I've got front brakes. Not the greatest of brakes but I've read that Honda engineers of the day purposefully built that brake system to underperform because disc brakes were new to production motorcycles at the time and there was concern that too many folks unused to front disc brakes would grab too much brake up front and lose control. Maybe that's true, in any case I'm seriously considering adding a second disc up front. The right fork leg has the necessary mounting hardware and the rest of the brake hardware up front is designed so that it can be used on either side of the wheel. But that project is for the future.
Suspension - I knew at the very least she needed springs - the bike hardly leaned over on the sidestand and it was a herculean effort to pull her up onto the center stand. I didn't want to spend an arm and a leg though, so after some internet searching I settled on Progressive Suspension brand components:
Progressive Suspension 11-1106 fork springs ($60 - found a good ebay deal)
Progressive Suspension 12-1204B 12 Series 13in. Shocks ($167)
Progressive Suspension 03-1394C 12 Series Springs (70-120 psi) - Chrome ($82)
The fork springs were noticeably longer than the old springs, so much so that it was difficult to re-install the fork cap bolt.
The owners manual calls for 10-30, but I used Maxima 10W fork oil. Apparently there were no fork specific oils available back when these bikes were being build. The spec in the owners manual only gives an oil fill volume, no spec on oil height in the fork tube. Per the instructions that came with the fork springs, I filled the fork tubes to a height of 140mm with springs out and forks fully compressed after cycling the forks up and down a few times to remove trapped air. I had already replaced the fork seals with All Balls Racing Motorcycle Fork & Dust Seal Kit 56-137.
The spring rates on both front and back are slightly higher than OEM, hopefully appropriate for a fat old guy. The rear shocks fully extended length is 1/2" longer than stock. I was worried that might shift the fork geometry towards instability but so far that is not a problem. I haven't put enough miles on her to give a proper evaluation of the suspension mods, but I can tell you that now there is a good lean on the side stand and she rolls right up on the centerstand.
Next on the to do list are new Avon AM 26 Roadmasters to replace the ancient Dunlops!
