Clutch not engaging after oil change

[WIX-ONE]

In todays episode of "what's he broke now?"

 

Changed the clutch oil, Drained old out and replaced with 260mm of new but now the clutch doesnt engage at all.

Thought it could need bleeding so i first filled from the bleed nipple, then as that didn't work bled all the fluid out and refilled again but still not working and i'm out of ideas?

Also what a stupid place to put that bleed nipple, every video I've watched has an easy access one not a stupid angled one....

Also i need to replace the drain plug as the allen thread has rounded, can i get a generic one from anywhere (UK) and what size is it as the parts list doesnt state the size?

 

Cheers

[trapezeartist]

When you say "clutch doesn't engage", I assume you mean it doesn't disengage. Assuming it worked before you changed the clutch fluid, the only possibility is air in the system. Although motorcycle hydraulics seem to be notoriously difficult to bleed, the clutch really shouldn't be too bad as there is a continuous gradient up from the slave cylinder to the master cylinder. Filling from the bleed nipple end should be the easiest as you will be pushing the air uphill. I've never done the clutch but when I did the front brake I finished with lots of tapping of the brake line near the master cylinder and watching for tiny bubbles coming out into the reservoir. With that and a bit of pumping I got there in the end. The only other possibility I see for your problem is that you have a big chunk of air trapped in the slave cylinder. Try lying the bike towards its left side.

 

[WIX-ONE]

Yeah that's the one haha. 

I'm thinking it is a bubble in the slave as I've bled it probably 6 times now and changed the master cylinder cover. I'm going to bleed again from the nipple now I've got more oil delivered but nice one, I'll try leaning it to work it out. 

Would disconnecting the hose and filling into the hole work?

 

[motovita]

On 6/17/2025 at 4:50 AM, trapezeartist said:

When you say "clutch doesn't engage", I assume you mean it doesn't disengage. Assuming it worked before you changed the clutch fluid, the only possibility is air in the system. Although motorcycle hydraulics seem to be notoriously difficult to bleed, the clutch really shouldn't be too bad as there is a continuous gradient up from the slave cylinder to the master cylinder. Filling from the bleed nipple end should be the easiest as you will be pushing the air uphill. I've never done the clutch but when I did the front brake I finished with lots of tapping of the brake line near the master cylinder and watching for tiny bubbles coming out into the reservoir. With that and a bit of pumping I got there in the end. The only other possibility I see for your problem is that you have a big chunk of air trapped in the slave cylinder. Try lying the bike towards its left side.

 

 

21 hours ago, WIX-ONE said:

Yeah that's the one haha. 

I'm thinking it is a bubble in the slave as I've bled it probably 6 times now and changed the master cylinder cover. I'm going to bleed again from the nipple now I've got more oil delivered but nice one, I'll try leaning it to work it out. 

Would disconnecting the hose and filling into the hole work?

 

 I think you guys are referring to hydraulic fluid that operates the clutch but the question is about the gearbox/clutch oil that the clutch operates in. I have no idea how that could interfere with clutch engagement. Maybe we'll get the rest of the story.

[WIX-ONE]

10 minutes ago, motovita said:

 

 I think you guys are referring to hydraulic fluid that operates the clutch but the question is about the gearbox/clutch oil that the clutch operates in. I have no idea how that could interfere with clutch engagement. Maybe we'll get the rest of the story.

Yeah it is a confusing one as it stopped working after i'd changed the clutch oil which really shouldnt have affected anything.

An update is that it now works.

I took it off the lift stand and lay it on its side, pumped the lever a few times and gave the area near the bleed nipple some taps and when i stood the bike back up it worked perfectly.

Now the weird bit, as soon as i put it back on the stand it wouldnt work, take it off the stand works fine???

So it could've actually been working all the time as i'd kept it on the stand since it stopped working while i had it in bits.

I'm going to take it out in the morning and give it a proper test and at least its got new mineral oil 🤣

[motovita]

5 minutes ago, WIX-ONE said:

Yeah it is a confusing one as it stopped working after i'd changed the clutch oil which really shouldnt have affected anything.

An update is that it now works.

I took it off the lift stand and lay it on its side, pumped the lever a few times and gave the area near the bleed nipple some taps and when i stood the bike back up it worked perfectly.

Now the weird bit, as soon as i put it back on the stand it wouldnt work, take it off the stand works fine???

So it could've actually been working all the time as i'd kept it on the stand since it stopped working while i had it in bits.

I'm going to take it out in the morning and give it a proper test and at least its got new mineral oil 🤣

 You mentioned an Allen head drain plug, maybe if you post a photo of that plug and it's location perhaps the mystery can be solved. Depending on the year and model of your bike you may not have a gearbox.

[WIX-ONE]

12 minutes ago, motovita said:

 You mentioned an Allen head drain plug, maybe if you post a photo of that plug and it's location perhaps the mystery can be solved. Depending on the year and model of your bike you may not have a gearbox.

It doesnt have a gearbox mate its an Epure Race 21 so its just the clutch

The drain plug is this one  I just want to know if i can get a generic one the same rather than having to get a specific one ordered in.

[konrad]

On 6/7/2025 at 9:36 AM, WIX-ONE said:

Also i need to replace the drain plug as the allen thread has rounded, can i get a generic one from anywhere (UK) and what size is it as the parts list doesnt state the size?

 

Fill and drain bolts are both M12 x 1.5