Clutch slip

[Bikebear]

Went for a ride up thr Gillies this morning and noticed when I pulled out of a corner in 2nd gear the clutch started to slip. Revs were around 4500 and as I accelerated fairly hard the engine would rev but the bike wasn't pulling. I changed the oil a few weeks ago and took it for a ride and didn't notice any issues then. Could it be time to get a set of clutch plates for the bike? I'm running a Penrite semi synthetic that I've used before so I don't believe it's the oil. It only happens when the bike is in a low gear and I give it a handful. Any thoughts.

[Brock]

How many Ks on the bike...

Check the oil to make sure it doesnt have friction modifiers..

I use the Penrite 15/40 Diesel oil, no problems with that, I'm at 140000KJs.

[Bikebear]

The oil I've used is Peneite HPR Diesel 10 10W40 semi-synthetic, this is suitable for wet clutch bikes and it is JASO MA rated.

The bike has nearly 88000 kms so I'm surprised by it doing this. I'm wondering if the clutch wasn't releasing properly so I'm going to get a kit to overhaul the master and slave cylinders and put new clutch fluid in. If it still plays up I guess I'll have to do some surgery and check the plates and springs.

It only slipped under heavy load (2nd gear with a handful of revs) so maybe it needs a set of springs, these are pretty cheap on ebay (EBC heavy duty) so I might get some anyhow.

[Scarlett Thunderbolt]

Sorry to read about your clutch problems. Hope you can get it sorted soon, but if the Golden Brown is still a nogo by the Cairns RTE, we hope that we will still be able to meet up with you for a curry.

All the best. John & Kate.

[Bikebear]

Ordered slave and master cylinder kits for it today they should be in by the weekend. I think this will solve my problem. The bike WILL be running for the RTE weekend.

[saaz]

Strange that it is slipping at such a low mileage. Mine has 216,000kms on it and still original clutch as far as I know. Some junk in the clutch hydraulic system could be the problem. Ex police bikes used for escort duty are a bit more know for this problem as lots of revs and clutch slipping.

[Scarlett Thunderbolt]

 

[Pezzz]

I did my clutch at 52000km as it would slip when overtaking in high gear or sometimes when accelerating hard off the lights.

[Bikebear]

Got the master cylinder kit and the complete slave cylinder (Honda don't sell a rebuild kit) today, I'll get these in this weekeend and see how it goes.

[Bikebear]

Well, I've removed the old slave cylinder and found that it was bypassing the seal and also appeared to be sticking so I've replaced it completely.I put a kit through the master cylinder, it was pretty grungy inside so it has been fully cleaned. Everything together then time to bleed it... except bleeding it just isn't happening. I've pulled the master cylinder apart twice to ensure I've put it together properly, disconnected the lines and blown through them to ensure they aren't clogged and still no joy. Has anyone had any experience with getting the system working after pulling it all apart.

I'm pretty pissed off right now.....     

[saaz]

It can be a pain. A vacuum bleeder can do it, but at a pinch attaching a hose to the opened bleeder on the slave and sucking on it while pumping should get the master cylinder to pump, then bleed as normal.

[Bikebear]

I'm gonna see if the mechanics at work have a vacuum bleeder tomorrow, just pissed off at what a pain it is.

[HunterTodd]

Hi,


I had the same problem with my st1300.  Problem turned out to be corrosion in the bleed back port.  I put a fine wire through it thinking that was sufficient.  It made the slipping worse.  It is critical that you bring the hole back to bare metal ir replace the cylinder itself.  If you dont pieces of corrosion continually dislodge blocking the bleed back port and causing ckutch slip..  I used oxy tip cleaners.  The smallest was too small the second was about right but I put the third smalesst in and it did trick  haven't had a slip since.  Cheers

[Bikebear]

I ended up buying a hand vacuum bleeder for $55 from the local tool store and tonight the young fella and I got to work, after finding one banjo connection was a little loose and sucking air we got the clutch bled and it feels very good. Now to get it out on the road and test it out.

I'm getting a collection of specialised tools now, I've decided to buy the tools I need so when I get around to working on my project bike I'll be able to do all those little things that cost a load of money for someone else to do.

[Bikebear]

Took the bike out today and had a spirited ride up the Gillies and no clutch slip    .. however I do seem to have a vibration through the bike, I did have a new tyre fitted but it isn't related as I can pull the clutch in and coast and it's fine, it seems to be related to the motor. I did change the oil recently and I noticed today the oil level is above the top mark, I've seen somewhere that a higher oil level can lead to vibration in the motor,..

Any ideas from the brains trust??

[Brock]

If the oil is to high, it may contact the crank and cause a vibration, may an idea to drain a little out.

[Bikebear]

Will give that a go..

[saaz]

Some STs seem to prefer the oil level to be half way, mine did not care

[Bikebear]

Took GB out for a run today after dropping the oil level to a point between the marks and it was sweet, no vibration. Looking forward to the ride this weekend even though it has been shortened.