www.DRRiders.com

A Dedicated Suzuki DR650 forum for DR650 riders to share their knowledge, experience and adventures!
It is currently Wed Sep 20, 2017 2:10 pm

DRRIDERS.COM Search - powered by Google

DRRIDERS Member Location Map

Place yourself on the map here!

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 81 posts ]  Go to page 1, 2, 3, 4, 5 ... 9  Next
Author Message
PostPosted: Sun Jul 07, 2013 5:11 pm 
Offline
Adventure Rider
Adventure Rider
User avatar

Joined: Fri Mar 29, 2013 10:23 am
Posts: 1095
Location: Thessaly, Greece
Well, after the chicken menace wiped any post of mine a few months ago, I reposted any things that might be of some value except the juicy original post at http://drriders.com/topic6143.html . Since I consider this a simple money saving tip that can be applicable to many guys trying to figure out their slipping clutch troubles, I repost it here afresh as good as I remember the data as I cannot remember exactly what my original post was.
=====


Short Version:

So your clutch is slipping more and more at ever less engine load as mileage accumulates while commuting in hot Summer days?
Or you got caught up at some nasty low speed trail and you had to slip you clutch overtime and now it slips big time, all the time?
First things to check are the obvious ones: Clutch cable slack and free moving as a tight spot could be the reason for intermittent slippage - what? You already checked this and all good?

Before you reach for your wallet and order a new clutch set, measure your clutch pressure springs located on the clutch pressure plate.
Suzuki claims their working length is good down to 33mm (1.3inch) free length. Well ... nope!
:nea:

What I found hands on in two occasions is that slippage starts before this limit even while the clutch plates themselves are well within service thickness and have not been burned up. I had quite a lot of slippage close to WOT at 33.3mm and big time slippage (unable to go over 70km/h) at 32.9mm free spring length.

Image

So check them along your existing clutch plates before buying a new clutch set. Friction plates may have long life still in them so no need to get new ones, just new (and better) clutch springs! (...or as Plonker has suggested, some shims could do the trick if you cannot get clutch springs but I have not tested this).

====

Long Version:

I got the bike with about 100 000 Kms. The donating friend and previous owner was using it as an everyday city commuter and general on-off traveler riding most of the time 2-up with his wife. At 70 000 km or so, he had replaced the worn out original clutch set with a pretty much unused second hand clutch set and this is what I got the bike with. Right from day one at my hands it was just slipping at WOT on high speed tarmac stretches. During the next 24 or so months I used the bike for about 12 000 more city kms and the slippage progressively worsened during hot congested city heavy hand :spiteful: use of mine. Not to the point that the bike was unrideable and I took this CVT alike behavior to good use against stronger bikes in between traffic lights drag races downtown tight Athens city boulevards. I tried to fight the problem with top of the self Motul and other full synth oils to clear possible friction plate smudge but no change - had no time to properly repair this as it was my main vehicle and could not afford any possible screwup of mine and no proper expert service.

However things worsened to the point it needed fixing but at the same time I left the big city life behind for the rural mountains I now live and the bike stood still for months expecting my wallet health to improve since I was sure it would require new clutch plates. I discovered a nearby breaker who had a similar XF650 Freewind engine and he was willing to sell me the looking good clutch set and springs for cheap. So I dismantled my DR's clutch only to find out that the XF's looking good plates were in about the same condition to my existing clutch plates - only the clutch pressure springs were found longer at 34.2mm vs mine in-service-limit 33.3mm.

Image

So I put in there the XF's good set (police bike rear ended), the XF's springs, the cheapest 10W-40 oil in the market and go for a spin on a 30C day. The clutch feels and behaves perfectly so I go try an unknown uphill trail. The trail gets tighter and tighter and my dead stock engine stalls easily so a lot of clutch use is in order to avoid this. Things get hot quite fast and I start to feel the clutch slipping again worse and worse in a few hundred meters. I barely make my way back to the tarmac and the clutch feels completely toast: Just holding 20-30 kph on the tarmac uphill and 70-80kph on the straights slipping like crazy on the tinniest throttle opening. All this in less than 16kms, yeap 10 miles after this long awaited repair :s_cry It certainly got hot as I had plastic parts of my boots melting on the clutch cover :OMG: so I was sure the clutch was toast for good.

Image
ImageNicely baked color, isn't it?!
Image

A few days pass and I discover that the previous owner between various other stuff had also supplied brand new looking OEM clutch springs that measured at least 35mm long (maybe 35.5?).
So I decide to look into my clutch again and to my surprise I see the XF's friction/metal plates in pretty much the same condition I put them there - only the oil got cooked and smudged. Since they were 0.1mm thinner than the DR's plates I took out, I put a mix of the 2 sets based on scientific criteria (which plates shined best on the sun) and the brand new springs I discovered. Do a couple of cheapo oil flushes and went for a ride with the same cheapo oil.
And ... all good! I still have this setup for the last 1500 or so kms and it behaves flawlessly! Mixing two slipping clutch sets should be a recipe for a slipping clutch again, shouldn't it? Well, not! Just have pressure springs long enough! How long? Hmm, let me guess here since other factors as the big concave washer spring must be taken into account as well (I changed it and not measured any possible deformation) and how polished the discs are due to wear. I suppose that 34mm should be considered a safe service limit for OEM springs - adding numbers from whatever memory is a bit fuzzy and I cannot give a solid number for sure surfacing from my experience.

What I was astonished to find out was that a nice 2nd hand 34.2mm OEM spring shrunk to just 32.9 mm over less than 500 meters of heavy continuous slipping to get through a very tight trail in a Summer day. Was totally sure I fried the clutch plates but nope: Cheapo spring material a.k.a. Suzuki cheapo. Talk about cutting corners from the production process! Damn bean counters! :shoot:

_________________
10 ADAPT
20 MOVE ON
30 GOTO 10


Top
 Profile  
 
PostPosted: Sun Jul 07, 2013 6:30 pm 
Offline
Member Servant
Member Servant
User avatar

Joined: Fri Sep 10, 2010 10:22 am
Posts: 9819
Location: Mackinaw City, MI, USA
Nice wriet up Mi_ka! :clapping: Stickie!

_________________
- mxrob -


Top
 Profile  
 
PostPosted: Sun Jul 07, 2013 7:12 pm 
Offline
Adventure Rider
Adventure Rider
User avatar

Joined: Wed Aug 15, 2012 3:40 pm
Posts: 1442
Location: Atlanta, GA
Location:
Are there better quality aftermarket springs out there?
..a

_________________
Image


Top
 Profile  
 
PostPosted: Sun Jul 07, 2013 8:11 pm 
Offline
Member Servant
Member Servant
User avatar

Joined: Fri Sep 10, 2010 10:22 am
Posts: 9819
Location: Mackinaw City, MI, USA
eflyguy wrote:
Are there better quality aftermarket springs out there?
..a


Yes.

http://www.barnettclutches.com/936/suzu ... 650se.html

_________________
- mxrob -


Top
 Profile  
 
PostPosted: Mon Jul 08, 2013 11:09 am 
Offline
Adventure Rider
Adventure Rider
User avatar

Joined: Fri Mar 29, 2013 10:23 am
Posts: 1095
Location: Thessaly, Greece
I just had a better look at thickness numbers trying to figure out safe OEM clutch spring length.
It seems Suzuki has not provided worst case data on the DR & XF service manuals so clutch slipping can start much sooner than even 34mm long springs.

Image

Both service manuals report standard friction plate thickness 2.9-3.1 mm & minimum 2.6mm for all 8 fiber plates (nr.10&12) and minimum spring free length at 33.0 mm. No note on metal plates (nr.8&11) thickness (only permitted distortion) or concave washer spring (nr.7) height or clutch pressure plate (nr.4) thickness or the sleeve hub (nr.5) mounts height as all these play some role on total pressure spring preload which dictates how strong the clutch plates are pressed together when the clutch lever is released by the rider.

When I first replaced my so-so slipping clutch, I remember that I measured the same thickness for all metal discs of the XF & DR's sets and changed only the fiber discs as well as the springs leaving everything else as it was and went from a slipping clutch to a non slipping one.
This means, I took out 33.3mm springs and eight 3.0mm friction plates.
I replaced them with 34.2mm springs and eight 2.9mm friction plates.
This means I had 8x0.1mm less thickness preload on the springs so their preloaded length was effectively 34.2-0.8=33.4mm.
So the only real difference has been just 0.1mm of spring preload and a bit less polished fiber discs - this was enough on my stock engine power to stop any clutch slippage!

So if we say 33.4mm is the minimum spring length then all good? Nope once more! :nea:
Suzuki states minimum fiber thickness down to 2.6mm which is 0.4mm less than the original slipping clutch I got. So if all fiber discs are worn to their specified minimum we get 8x0.4=2.4mm less total thickness which should be added to the aformentioned ok length so 33.4+2.4=35.8mm spring length to not have slippage if the fiber discs are worn down to their minimum - that is a whole 2.4mm longer than the specified 33.0mm minimum spring length !!
And this without taking account any wear on metal discs, pressure plate,concave spring which would add even more needed spring length.
By the way, I went through the DR parts carton and measured my DR & XF metal discs (nr.11) at 1.55mm and the concaved washer spring (nr.7) at 2.7mm high. The thicker metal plate (nr.8) is 2.0mm and it contains a groove were the concaved washer spring touches which must be 0.1-0.2 mm deep but it is not easy for me to measure this - just report on finger nail assessment.

So guys, check all numbers in conjunction to each other and the final outcome would be judged on the road - if it slips, then just fix it and don't rely on stated service manual numbers, at least for this part of your engine...

Overall it continues to impress me, if I got the numbers right and if we set fiber polishing and other minor factors aside (the bottom line is my current ok clutch is a mix of parts of two slipping clutches so the only major difference is pressure springs length only):
33.4mm - no slippage
33.3mm - a lot of slippage on WOT
32.9mm - Bike almost unrideable, slippage on the lightest touch of load/throttle

Now I wonder if I had got fuel money, whether I would seat and write all these mind burbles here and whether anyone will find any use for them :wacko:

_________________
10 ADAPT
20 MOVE ON
30 GOTO 10


Top
 Profile  
 
PostPosted: Tue Jul 09, 2013 12:30 pm 
Offline
Single Tracker
Single Tracker
User avatar

Joined: Tue Feb 12, 2013 7:56 am
Posts: 223
Location: Timmins ON The Land Of 2 Seasons: Rainy & Snowy
Good information, thanks for the write up.

_________________
'03 DR-X650: Continental TKC80 Front, Shinko 244 rear; 14 tooth front sprocket; BarkBusters; Procycle case armor; Warp9 skid plate, shifter, and clutch lever; Sargent low seat with Sit & Fly cover; Acerbis tank; Renthal CR high bars; RMZ forks; Buell headlight mod, future KX450F rear shock.

'15 GSX-S750


Top
 Profile  
 
PostPosted: Tue Jul 09, 2013 12:41 pm 
Offline
Adventure Rider
Adventure Rider
User avatar

Joined: Wed Mar 30, 2011 2:01 pm
Posts: 2312
Location: Apex, NC
Great information to have...thanks for sharing.

I wonder if 4 washers could be used to temporarily lengthen the springs in a trail-side emergency? It should work if the washers were the correct diameter/thickness. It probably wouldn't last too long since the springs are already starting to creep but it might get you back to some asphault and would be easier to carry than replacement springs...

_________________
'08 Suzuki DR 650SE
'99 Suzuki DR 350SE
'07 Buell Ulysses XB12X
'65 Honda CB160
'06 Honda CRF50F


Top
 Profile  
 
PostPosted: Mon Jul 29, 2013 1:58 am 
Offline
MSF Student
MSF Student
User avatar

Joined: Tue Jun 05, 2012 5:01 pm
Posts: 68
Location: Varna, Bulgaria
Location:
My clutch starts slipping when I replace my carb with FCR and properly tuned it.
First I think rear tire might be slipping as its a sh*t(Maxxiss M6006) because its slipping at 1st and 2nd gear only but then I look at my tacho and realize the clutch is slipping under heavy throttle use.
This weekend bike will have hard live as we'll make 350 kms offroad trip and I dont want my clutch to fail somewhere in the middle of nowhere.
I found TRW Lucas springs in my town so I will try them, they claim 10% more strength and are really cheap at 10Euro($15) for the set.


Top
 Profile  
 
PostPosted: Mon Jul 29, 2013 5:24 am 
Offline
Adventure Rider
Adventure Rider
User avatar

Joined: Fri Mar 29, 2013 10:23 am
Posts: 1095
Location: Thessaly, Greece
Hey Ivan , if no bother please post if clutch plates were ok and the outgoing springs length.

_________________
10 ADAPT
20 MOVE ON
30 GOTO 10


Top
 Profile  
 
PostPosted: Mon Jul 29, 2013 1:29 pm 
Offline
MSF Student
MSF Student
User avatar

Joined: Tue Jun 05, 2012 5:01 pm
Posts: 68
Location: Varna, Bulgaria
Location:
Mi_ka wrote:
Hey Ivan , if no bother please post if clutch plates were ok and the outgoing springs length.

I measure plates before 8000km and they were just below 3mm so I'm pretty sure they are at same thickness now.
I bet on springs.
Tomorrow will go to shop to measure and buy new TRW if they are at least 35mm long.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 81 posts ]  Go to page 1, 2, 3, 4, 5 ... 9  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  



Forum hosting by ProphpBB | Software by phpBB | Report Abuse | Privacy