UK Monster Owners Club Forum » .: Technical :. » Engines, Clutch, Gears » Clutch Spongy

Reply
 
Thread Tools Display Modes
Old 06-06-2019, 09:58 PM   #1
CarloL
Registered User
 
Join Date: Apr 2017
Location: Dublin Ireland
Bike: M900
Posts: 298
Clutch Spongy

Monster 1997 900
Mileage 8K

clutch fluid near 12 months old
changed the clutch slave for a new oe about 18 months ago (no signs of leaking)
Clutch discs still Original

Clutch feels spongy , lever will still spring back but goes all the way to the bar; pressure plate does not appear to have alot of movement , about 1cm

Bike drives fine, but very short bite point ; not alot of threshold in the lever for slipping the clutch

On aside note , I have slip on Termi's on , do you guys run a colder plug? Need to do anything to accommodate the exhaust ?
CarloL is offline   Reply With Quote
Old 06-06-2019, 10:26 PM   #2
Albie
Fanactical volunteer
 
Albie's Avatar
 
Join Date: Oct 2003
Location: Kent
Bike: M900
Posts: 9,028
Air in system is my bet. Cable tie lever in overnight after trying pumping it a dozen times prior. If its ok in morning then air is your problem. You could also remove your cover and rubber and carefully pump in and out then hold in. Often or not you will see small bubbles rise to surface.
Albie is offline   Reply With Quote
Old 06-06-2019, 10:29 PM   #3
CarloL
Registered User
 
Join Date: Apr 2017
Location: Dublin Ireland
Bike: M900
Posts: 298
Was thinking of air , but how would air enter the system after all this time ?

Will change the Fluid the weekend
CarloL is offline   Reply With Quote
Old 06-06-2019, 11:44 PM   #4
Nickj
Too much time on my hands member
 
Nickj's Avatar
 
Join Date: Jun 2007
Location: Forest Of Dean
Bike: S2r
Posts: 3,187
It's amazing how much does sneak in .. My back brake stopped working and as well as a very rusty retainer pin literally half of the system was filled with air.
I've had similar experiences with a clutch on a 750, I think it was a tiny bit of wear on the slave piston and seal.
__________________
"The final measure of any rider's skill is the inverse ratio of his preferred Traveling Speed to the number of bad scars on his body." Song of the sausage creature
Nickj is offline   Reply With Quote
Old 07-06-2019, 01:02 AM   #5
vince53
Registered User
 
vince53's Avatar
 
Join Date: Sep 2018
Location: taunton
Bike: M1100s
Posts: 41
yep I'd say its air if there's no leaks ? , and I'm with Albie cable tie trick works wonders but like he said leave it over night for it to work ...oh just make sure the clutch res is on top mark when bike is upright and bars are strait … * )
vince53 is offline   Reply With Quote
Old 07-06-2019, 03:18 AM   #6
slob
.
 
slob's Avatar
 
Join Date: Jul 2003
Location: East London
Bike: Multiple Monsters
Posts: 9,702
Clutch life depends on riding style/enviroment:
If you go for gentle Sunday rides in the country they might last 35k miles or more,
If you commute in a city, traffic lights might reduce this to 15k miles,
If your name is Carl Fogarty they last about 90 minutes.

Fluid should be changed at least every 2 Years.
How long had bottle been opened 1year ago?
Potential for air in system
Disc pack height the important measurement here, some kind anorak ;-) will give us a number shortly, haven’t checked one lately so would need to look up.

Sounds like you’re describing air in system.
Slip? you mean smooth release?
1cm is a lot, do you mean 1mm?

Brake fluid v.hygroscopic (absorbs moisture from atmosphere)
Hence 2 year service schedule. Water boils at 100c (@1bar), steam
is gas (not air) same effect.

Don’t keep opened bottles of DOT4. Buy smallest bottle you can.
Take all bottles open more than 1 month to local recycling.
Write date on bottle when you open.
Vapour lock in brakes much scarier!

My bet is bleeding will fix, Albie’s method may or may not work... explanation complex.

Exhausts & plugs... whole other thread.
slob is offline   Reply With Quote
Old 07-06-2019, 10:21 AM   #7
CarloL
Registered User
 
Join Date: Apr 2017
Location: Dublin Ireland
Bike: M900
Posts: 298
Thanks lads

I always use only unopened fluid, disgard the rest

Think I found the issue, small area of the clutch line, down by the slave was resting against the engine casing, causing the fluid to heat up

Was alot better driving in this morning, more consistent
lever,

Will do a full fluid refresh the weekend
CarloL is offline   Reply With Quote
Old 07-06-2019, 11:35 AM   #8
Albie
Fanactical volunteer
 
Albie's Avatar
 
Join Date: Oct 2003
Location: Kent
Bike: M900
Posts: 9,028
Quote:
Originally Posted by slob View Post

My bet is bleeding will fix, Albie’s method may or may not work... explanation complex.

Exhausts & plugs... whole other thread.
I say this only as trying to see whether or not air is still there rather than going through the whole process of refilling and bleeding at slave. Obviously if you happy to redo the whole lot is entirely everyone's choice and my test is not guaranteed but I have never had it fail and also worked on rear brake in a similar fashion.
Albie is offline   Reply With Quote
Old 07-06-2019, 12:15 PM   #9
CarloL
Registered User
 
Join Date: Apr 2017
Location: Dublin Ireland
Bike: M900
Posts: 298
I do the over night cable tie trick, did it last time I bled the brakes and clutch

Needs new fluid, will just do the whole lot again
CarloL is offline   Reply With Quote
Old 07-06-2019, 07:41 PM   #10
slob
.
 
slob's Avatar
 
Join Date: Jul 2003
Location: East London
Bike: Multiple Monsters
Posts: 9,702
i know albs, in theory it shouldn’t work but it often helps.

carlo, i tried to answer in strict order of your original post,
v difficult, as in hospital with only small smartphone.
slob is offline   Reply With Quote
Old 07-06-2019, 08:01 PM   #11
Darren69
Transmaniacon MOC
 
Darren69's Avatar
 
Join Date: Sep 2013
Location: Sutton In Ashfield
Bike: Multiple Monsters
Posts: 6,009
Another trick is to bleed the mc at the top banjo as air will collect there and not enough displacement of the fluid/piston to shift it. Have had to do that a few times and you can hear the air coming out. They fit bleed nipples on some of the later mcs too to make it easier to do the same.
__________________
Roast Beef Monster!

Termignoni and Bucci - Italian for pipe and slippers!

S4 Fogarty, S4R 07T, 748, Series 1 Mirage
Darren69 is offline   Reply With Quote
Old 07-06-2019, 08:07 PM   #12
CarloL
Registered User
 
Join Date: Apr 2017
Location: Dublin Ireland
Bike: M900
Posts: 298
Quote:
Originally Posted by slob View Post
i know albs, in theory it shouldn’t work but it often helps.

carlo, i tried to answer in strict order of your original post,
v difficult, as in hospital with only small smartphone.
Thanks Slob

Got it sorted , even though Brake and clutch fluid was changed late last summer ; was black and I am running SS lines

The clutch fluid was low and full of air ; surprised it evaporates relatively quickly based on 2 year schedule
CarloL is offline   Reply With Quote
Old 08-06-2019, 02:38 AM   #13
slob
.
 
slob's Avatar
 
Join Date: Jul 2003
Location: East London
Bike: Multiple Monsters
Posts: 9,702
Quote:
Originally Posted by CarloL View Post
Thanks Slob

Got it sorted , even though Brake and clutch fluid was changed late last summer ; was black and I am running SS lines

The clutch fluid was low and full of air ; surprised it evaporates relatively quickly based on 2 year schedule
It almost always turns black, not a problem
Sounds like you do have tiny weep... going onto chain or into engine oil, letting air in
It doesn’t evaporate, is not a ‘consumable’ like eg oil

Last edited by slob; 08-06-2019 at 02:40 AM..
slob is offline   Reply With Quote
Old 08-06-2019, 08:45 AM   #14
CarloL
Registered User
 
Join Date: Apr 2017
Location: Dublin Ireland
Bike: M900
Posts: 298
Will Keep an eye on the level
CarloL is offline   Reply With Quote
Old 08-06-2019, 10:37 AM   #15
CarloL
Registered User
 
Join Date: Apr 2017
Location: Dublin Ireland
Bike: M900
Posts: 298
What do you guys recommend for a slave , Oberon?
CarloL is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT. The time now is 02:52 PM.

vBulletin Skins by vBmode.com. Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.