Clutch drag

[sanemancured]

Hello all

My clutch is dragging. I’ve suspected it for a while and yesterday I tried turning the rear wheel by hand in 1st gear with the clutch disengaged. It’s much harder than in should be. 

I usually back my bike out of the garage in gear with the clutch in and it’s been hard work. 

I’m wondering if anyone has had similar issues?

I’m going to remove the starter motor and bleed/flush the hydraulics, hopefully today if I can find some suitable mineral oil. 

Peter

[Grumpy Goat]

My clutch is dragging. I’ve suspected it for a while and yesterday I tried turning the rear wheel by hand in 1st gear with the clutch disengaged. It’s much harder than in should be. 
...
I’m going to remove the starter motor and bleed/flush the hydraulics, hopefully today if I can find some suitable mineral oil.

Peter,

This is the first I've heard of this being reported, and am interested to know what you find. I think that your approach makes sense since it could be that somehow you have air in the system. With air in the system the hydraulic pressure would be less, leading to less effective disengagement. Question then is ..0 did air get in the system in the first place. Maybe some seals are going ...?

Looks like this is the fluid you need.

   

[sanemancured]

Thank you Wayne

I managed to find some fluid. No change I'm afraid. I'm about to take the bike for a ride and see if the clutch is slipping. It may need replacing.

The lever feels good. I've also checked the adjustment of the lever plunger and dropped the oil level in the sump a little.

Peter

[Oldrider51]

For a fluid you can also use Magura Blue Blood mineral. I have used this without any problems, It can be had from Amazon in various sizes, https://www.amazon.com/Magura-0721630-AC...117&sr=8-1

[sanemancured]

Thank you.

[sanemancured]

I think I’ve got to the bottom of the problem. When I operate the clutch with the reservoir cap removed I can see a fine emulsion being drawn into the reservoir when releasing the lever. I think the master cylinder needs replacing.

Peter

[Grumpy Goat]

I think I’ve got to the bottom of the problem. When I operate the clutch with the reservoir cap removed I can see a fine emulsion being drawn into the reservoir when releasing the lever. I think the master cylinder needs replacing.

Are you thinking the fine emulsion could be suspended bubbles? How did you conclude that it was the master cylinder that needs to be replaced? Just asking since I never serviced a hydraulic clutch before.

[sanemancured]

Yes Wayne.

After a few moments the lighter coloured circle of fluid disperses. The clutch sees a lot more use than the brake cylinder and through a greater travel (I rarely use gear shift assist). I suspect that the seals are worn and air is getting drawn in. The slave cylinder has a weep hole and that’s dry so it’s not leaking fluid past the seals. If it were drawing in air I don’t think it would display in the same way as it does at the master.
Just as well I have a 2nd RS in the house ?

I have just bought a used one, 15,000 miles from a 2020 1250RS.

I’ll update. If it doesn’t work I’ll have another think.

Peter

[Grumpy Goat]

Thanks for the clarification, Peter. Looking forward to hearing of the resolution.

[sanemancured]

A guy on UKGSer suggested that his clutch started to drag before slipping at 42,000 miles (strange). I've more miles than that so I took the bike out and tried to get the clutch to slip. Full throttle in 2nd does lift the front wheel! No slippage apparent.

Bleeding/flushing the clutch requires removal of the starter motor. I found that removing the exhaust system and having a short 30 Torx L tool made that job easier.

I flushed through with new fluid. I didn't have a hose of a small enough diameter (it's a tiny bleed nipple- Magura cycle sized) to look for air coming out and I just bled it into a bowl. The clutch was better. Not perfect but I could now turn the rear wheel by hand in 1st much easier than before. I was struggling to push the bike out of the garage in gear previously.

When cycling the clutch with the reservoir open I could see an emulsion of micro bubbles entering the reservoir when I released the lever. A symptom of failing master cylinder seals.

I rarely use gear shift assist and on the roads I ride I'm up and down the box all the time. So the master cylinder has seen a huge amount of use.

The master cylinder isn't a serviceable item. I bought a low mileage one from a R1250RS from eBay.

Having acquired the correct size bleed hose I went back to removing the exhaust system and starter motor etc.... I pulled the slave cylinder out to check it wasn't leaking and had a shock when oil dripped all over the floor, thankfully it was engine oil, red not blue. So the slave is good. I couldn't get the pushrod to separate from it though.

I fitted the replacement master cylinder and bled though with new fluid. I even back flushed by pushing the slave cylinder in several times, no air!, no micro bubbles.

New seals on the hose, new exhaust gaskets and the bike is all good. In 1st the rear wheel turns quite freely with the clutch held in.

Sorted. Updated in case anyone has the same issues.

Peter

[Grumpy Goat]

Excellent write up - thanks Peter. Glad you have it sorted.

[sanemancured]

I was out for my first ride since changing the clutch master cylinder yesterday. I good 150 mile route through a variety of Cumbrian roads and weather. It was down to 9 Celsius coming over Shap summit!

Not only has the clutch dragging problem gone, I'm left wondering if a problem I've had with the bike from new is also resolved.

Gear changing is now much cleaner, less 'notchy'. These issues often deteriorate slowly and it become apparent how much so when the fix is both complete and instant.

I rarely use Gear Shift Assist, in part because it is mechanically better the conventional way. I was playing around in town using it from third down to first a few times and it was perfect! I was particularly impressed with 2nd to 1st. Going up 1st to 2nd in low load situations was the usual lurch.

From new I've had an issue with the gearbox that I've learnt to live with. 2nd to 3rd, clutched change, it baulks in 2nd and needs some extra force to move the lever. Others have had this issue and it usually happens about every 10th change as a guess. Yesterday, 150 miles and it didn't occur once.

So I'm very pleased. Bike is going well and I also had a new Metzeler Roadtec 02 on the front (Roadtec 01SE on the rear). It was excellent as I've come to expect from Metzelers in mixed conditions.

Peter

[Grumpy Goat]

Great to hear Peter. Thanks for the update.

Can't say that I have had a similar shifting experience with my RS, but then I have all but given up hope that the gearbox on it is anything but "almost agricultural", especially compared to the Triumph. That said, the RS's gearbox gives me a sense of robustness which, so far, has lived up to the billing.