Weekend of 11/5/2022

The clutch on my 2012 Honda ST1300 had given up the ghost in September, cutting short a rainy journey out to Pennsylvania for a riding vacation with friends. After weeks of waiting for new clutch discs, plates, and springs to arrive, I set aside an available weekend to dive into the rather intimidating maintenance task of rebuilding the clutch. There were good articles available on the process on the trusty st-owners.com forum, which I’d reviewed several times. As a matter of fact, using the information I found there for this task finally prompted me to send in a donation in support of that site, which has helped me incalculably throughout my ST ownership.

The replacement of the actual clutch parts themselves didn’t really seem all that hard. But rather, the fact that I was cracking open the lower engine case of the bike for the first time had me as jittery as a junior-high schooler getting to third base. Like every other repair or maintenance I’ve tackled on this bike for the first time, I just needed to gather up the right tools and parts, then give myself plenty of time to tackle the job.

I had already removed the front and main side plastic cowling pieces from the bike. I drained the oil, and proceeded to remove the radiator and front wheel to gain access to the front of the engine block where the clutch cover is located. Then ensued several rounds of cleaning/rinsing everything with Simple Green to remove all the accumulated dirt and baked-on road grime from the front of the engine.

After removing the water pump cover, even more road grit was revealed and needed to be carefully removed.

At last, time for the big reveal!

The careful removal of the clutch over from the engine block required use of a specialized tool (a metal ruler) to try to keep a small chain cog from pulling off its shaft when pulling off the cover. All the online sources said “DON’T let that cog come out!” but didn’t really go into much detail as to why or how. Of course, it fell right off when I finally removed the clutch cover and the short chain running between it and a hidden sprocket behind the clutch assembly fell out of position, down into the engine well. Doh!

With the cover finally off, it was now time for the worst part of this entire job – removing the remnants of the old cover gasket.  Based on what I’d read, this would take more time than the rest of the steps put together, and that wasn’t wrong! I’d researched and talked to friends for recommendations on removing old gasket material from aluminum. The main concern is cleaning up the edges of the clutch cover and engine mating surfaces, without damaging the soft aluminum, to ensure a good seal with the new gasket after reassembly.

Solutions run the gamut from chemicals, to power tool attachments, to plastic scrapers, and I was prepared to try all of them. I picked up gasket remover, some plastic razor blade-like scrapers, and even a rotary air tool with attachments based on a YouTube video I’d seen.

I finally decided against using a power tool, based on recommendations from trusted sources about damaging the aluminum. The chemicals helped a bit after leaving them to soak overnight, but weren’t thorough enough to remove the really baked-on stuff. The plastic blades were pretty much a joke and more effort than they were worth. I finally resorted to the tried, true, and rather risky method of using a regular steel box-cutter blade at a very shallow angle to get most of the really tough stuff.

It took a few hours of painstaking work, but I’d mentally prepared for it, cranked up the tunes, and was determined to do it right to ensure I wouldn’t get any leaks through the new gasket after reassembly. I covered up the internals of the engine and the floor with rags to catch all the debris. There was actually something oddly satisfying after scraping off long chunks of gasket with a gently held blade and seeing clean undamaged aluminum in its wake. 😬

Once I was satisfied that I’d gotten everything I could get, I quickly got to work on changing out the clutch discs, plates, and springs. Pretty straightforward work and the old clutch plates looked as terrible as they’d felt while limping towards home on the bike.

Once the bolts were properly torqued, it was time to fish out that fallen chain and get it properly positioned on its hidden sprocket. With judicious use of a small dental mirror and a magnet, I was successful in realigning the chain and getting it back onto its intended path, from behind the clutch basket to the small removeable sprocket. I applied some Honda Bond gasket material in the recommended corners of the cover’s edge, laid on the new gasket, and then spent the next 1-2 hours cursing and sobbing while trying to get the damn cover to Just Get On There! With the various angles, corners and guide bushings, plus the water pump sprocket, it was a test of patience and my mental state after almost two full days working on this project.

Finally at almost 19:00 on the second day, after a slight tap in the secret spot, the cover simply decided to pop right back into place. Of course by now, some of the engine oil pooling in the bottom of the engine had dribbled over the gasket, so I had to take the cover OFF again to wipe all that up and soak up the excess for the next attempt, which was still a pain, but went much quicker.

My hands were cramped and tired from all the maneuvering, prodding, and pushing so I called it a night after bolting the cover on and carefully cleaning up around the edges to check for leaks on the morrow. The next morning, I saw no evidence of leakage from the gasket and began considering the arduous process of putting things back together.

First, while I had everything disassembled so far, I wanted to take stock of the coolant system components. This job gave me some opportunity and plenty of angles to inspect the coolant hoses where they meet up under the airbox. There was definitely evidence of long-term seepage, so I figured it was time to replace whatever hoses I could manage without ripping out the entire air filter box and throttle bodies from the top. Also, having gone through a few marginally successful attempts in the past to clean the packed in bugs and gunk out of the bike’s original radiator, I decided it was time to install the brand spanky new one that I’ve had sitting in a  box since 2019, along with extra hoses and clamps.

The hose replacement was tough to get through with my tired-out hands. I finally managed to get things seated securely, replacing the ones that had been seeping, as well as the main inflow and outflow hoses. The new radiator looked night and day better than the original, though I decided to keep the old one as a spare since I’ve had no actual problems with it yet.

Besides the valve check and shimming, this maintenance work had been the deepest I’d delved into the ST’s engine. It had been a bit nerve-wracking, especially in the days after while I anxiously checked the garage floor for any signs of leaks through the new gasket (there were none). On Monday, I filled the oil and coolant and got the bike started as soon as possible  to check for any leaks under pressure/heat. No issues spotted over the next 24h, so for Wednesday I proceeded with reinstalling the front wheel and took a short test drive around the block to ensure the clutch was now working before buttoning all the plastic back up again. It lives! It shifts! I was ecstatic that the bike didn’t just rattle to an explosive stop underneath me!. On Thursday, I got out for my standard little one hour local loop after work – all systems were go – time to ride this weekend!