I have a 2007 S2R 800 with a little over 15,000 miles on it.
Approximately a month ago, I checked the valves (very close to spec, so I left them alone), changed oil/filter and flushed the brake and clutch fluids (used DOT 4, can't remember the brand).
Left the bike in the garage until yesterday and battery died. Replaced battery and found that clutch fluid was gone, empty reservoir -- no apparent leaks.
Refilled clutch reservoir, bled the system and got firm lever (as normal).
Also removed/cleaned the slave cylinder and push rod.
When I was testing the clutch on the rear stand, I could not get the rear wheel to move with bike in gear and clutch engaged.
However, works just fine when riding.
Very confusing.
Questions:
1) Have others had the clutch DOT 4 fluid disappear? Are there common air bubbles that form with flushing the fluid that resolve over time or some such? Common slow leaks that are not apparent?
2) Why does the rear wheel not move when clutch engaged on rear stand with engine off? Does clutch action on the s2r depend on engine running? I am missing something...
Tried searching this forum and did not find anything.
Thanks in advance!
Slow leaks from slave cylinder seals or cracked bleed nipples can occur. The fluid may be hidden around the front sprocket area or leaked into the clutch push rod cavity up to the o ring seals. Have a look under the sprocket cover for moisture added to the normal gunk.
With the clutch working well it could take some hand force to turn the wheel in the way you describe. All works fine under load. Big resistance shows a dragging clutch.
Bleed and flush it again and spray foot powder around the areas that could leak. Thats an old trick I first heard of on this forum [thumbsup].
The leak will stain the powder.
Sometimes with leaky brake fluid you don't even need the powder...if the contact time was long enough just look for the blistered engine paint!
BK
For the fluid gone that is odd. Check the areas koko talked about. You must have a leak somewhere.
I know my S2R800 had a sticky clutch plate situation if I used certain oils. Example: I start the bike let it warm up and with the first clutch pull in you would either hear the plates get unstuck. If it didn't do that the first time I throw it into gear it would jolt forward a little and get them unstuck. Nothing wrong at all just something I had to remember before taking off so I wouldn't stall it cause they were sticking. Changing to a different oil ended up greatly lessening the issue.
My dealer had put a synth blend in and it made it stick every time. When I switched to Amsoil it went away almost completely. Mobile 1 4T still had it a little bit but not as bad as that damn synth blend.
Here is my link for some manuals. The S2R800 workshop manual is at the bottom if you don't have it already.
http://www.mikemo.org/bikes/manuals/ (http://www.mikemo.org/bikes/manuals/)
The only reason clutch fluid needs to be added between services is a leak. Most likely the slave.
Thank you! Very helpful.
Yesterday, I noticed a few drops of oily fluid under the bike after it has been parked for a few days (2-3) on the side stand.
Appears to be coming from the clutch slave -- as some have predicted.
I took off the clutch slave and the fluid seems to be coming from a small hole machined into the inner surface of the slave cylinder.
I did not see anything in the service manual about clutch rebuild or what that hole is supposed to do...
Circled below:
(http://i1250.photobucket.com/albums/hh524/evbernstam/S2R%20clutch%20slave_zpsgt5uejoh.jpg?t=1473442598)
Before replacing the slave, I wanted to make sure that it is indeed malfunctioning.
Is this due to a worn seal or o-ring? Is it an "overflow" mechanism and some leakage is normal after bleeding?
If it is due to a worn seal there a rebuild kit? My dealer did not seem to be able to answer that question.
Is it better to just replace the slave?
Do you recommend a used OEM? Aftermarket? If so, Oberon for $150?
Thanks!
I don't know if it has to be replaced, but if it does, I believe OEM is less expensive than aftermarket (for a change).
The APTC clutch is, IME, sensitive for clutch rod travel - it needs the full travel of a 26mm (OEM) to cover the distance from fully engaged to fully disengaged. 28mm is ok, but 29 and up ~not suitable. The tiny drag you get with larger slaves is probably not critical, but something to consider.
That slave is not rebuildable.
Replaced the slave with a used OEM. So far so good.
What lube do you recommend?
I put a bit of silicone lubricant (https://www.amazon.com/3M-08946-Clear-Silicone-Paste/dp/B005RNEH5O (https://www.amazon.com/3M-08946-Clear-Silicone-Paste/dp/B005RNEH5O)) on end of the push rod and external o-ring.
That paste will likely work fine.
I'd use any synthetic grease I had around.