Clutch plate replacement for the CBX1000.

Clutch plate replacement for the CBX1000.

When I did a full-throttle run, I suddenly felt a strange sensation where the engine revved up unexpectedly. It felt as if I unintentionally used half-clutch. It seems like the clutch has started to slip. Although there are some missing parts for the clutch plate replacement, it shouldn’t be much of an issue. One of the clutch plates is larger than the others, and that specific Honda OEM part is out of stock. However, as of 2022, aftermarket options are available for purchase.

For the replacement, you will need a special tool for the bolt securing the clutch center shaft. It’s a special nut that is tightened very firmly, so either air tools or someone strong will be necessary. While you can perform the job without a service manual, if you don’t already own one, this might be a good opportunity to purchase it. You might also want to get a parts list as well.

Pre-check – Important Points

I will first list the important points.

This is based on measurements taken at a later date. The size of the collar for the earlier model is 45mm, while for the later model, it is 43.8mm. The shape of the springs differs between the early and late models. While it's possible to force the springs to fit, it is not recommended. The clutch outer differs in shape for the CB1, SC03, and SC06 models. The newer the model, the more improvements have been made. In Japan, it seems that specialized shops can rebuild or implement improvements for the CB1 and SC03.

The friction plates consist of seven disc A's and one disc B. Disc B is larger, and it's no longer available from the manufacturer. Depending on the wear, it may not be necessary to replace it. The discs with cork attached are the friction plates, while the plain discs are the pressure plates. According to the service manual, the slits on the friction plates should all face the same direction. I tried alternating the assembly, but I didn't encounter any issues during operation. As for the friction plates, aftermarket sets are available, so it's better to purchase one of those. Disc B is also included in these aftermarket sets.

Pre-check – Other Cautions/Notes

When disassembling, there may be instances where readjusting the ignition timing is necessary. You won’t be able to make adjustments without removing the cover on the right side of the crankcase. Be sure to mark everything clearly before proceeding with the work. Align the timing with the 'F' mark. If you work with the bike on the side stand, oil won’t spill. However, if you use a center stand or similar, you will need to drain the oil.

Wear of the clutch and springs

The service manual states that the springs are 33.6mm, the friction plates are 3.1mm, and the pressure plates have a warp of 0.2mm. While these measurements are well within tolerance, I will proceed with the replacement. Since the clutch is composed as a set rather than individual plates, there is no option but to replace them. I have taken some photos during the work, though they may be a bit rough, so feel free to take a look if you're interested.

Photo Gallery

I am measuring the thickness of the old parts compared to the new ones. The thicker one is the new part. Ideally, I wanted to install the later model SC06 clutch outer, but I have installed the earlier model instead. The reason is that there were some unknown points regarding the necessary parts and compatibility while I was working. Since I am working in a rental pit, there are time constraints. There’s no need to rush the process, so I will properly prepare for the next oil change and switch to the later model clutch then.

Clutch plate replacement for the CBX1000.【summary】

Here are my thoughts after the test ride following the replacement. It was definitely worth it! I realized that the motorcycle I had been riding was slightly out of sorts. I also felt that the overall power had dropped before it started to slip.

When I put the bike on the center stand, I shift into low gear and squeeze the clutch. At that moment, the tire starts to spin. That’s how the mechanism works. Presumably, that is the correct state.

When I first got the CBX1000 twenty years ago, I mistakenly thought that this behavior indicated that the clutch wasn’t properly adjusted. When I asked questions on social media, there were many knowledgeable and kind people who shared information with me. I also provide detailed answers if I receive questions via email or other means.

Well then! See you again!