The Clutch FAQ
compiled & edited by Kristian #562
Please read the Disclaimer before attempting any work in this FAQ.
If you are looking for information about installation of Stiffer Clutch Springs see the Stiffer Clutch Springs FAQ
If you are looking for information about Clutch Rack & Pinion problems, see the Clutch Misc Probs FAQ
If you are looking for information about Clutch Adjustment see the Clutch Adjustment FAQ
If you are looking for information about Clutch Slippage see the Oil FAQ before considering Changing your Clutch!
New Clutch Plates and Springs Installation FAQ
by Kristian #562
This FAQ is about the installation of New Clutch Plates and Springs.
How do you know when they’re worn? What are the Symptoms.?
The Clutch slips (or rather the Plates slip), particularly when you drive up a steel hill in low gear.
BE AWARE however, that it’s a Wet-Clutch i.e. bathed in the same Engine Oil that lubricates the rest of your bike.
"One of the most probable reasons for a slipping clutch (assuming everything is adjusted OK) is the use of EC (Energy Conserving) rated oils. (Has an EC in the API - American Petroleum Institute) star logo. Not sure if you have them in HK or Yurp, or how they are marked (probably NOT with an API symbol!) but they are very common in the US, especially with the synthetic oils. The EC additives are VERY BAD for use with wet clutches, cause excessive slippage, and are difficult to "wash" out if used - might take several oil changes. In other BMW's with a dry clutch, using EC oils is common, so it's probably a common mistake in the service shop also."
When I took mine out at about 25,000 miles to replace the Springs, the old plates JUST looked like the new ones. So my guess is a LONG time.
I can’t tell you how many miles they’ll last there is no “Magic Number”, because it depends on your driving style, whether you do a lot of highway, or lots of clutch-work (i.e. slipping) in and around town, your engine oil type, how far you drove with low engine oil or perhaps how far you drove with emulsified engine oil when your water pump fails.
So before you go wasting some money and time on New Clutch plates, try fully synthetic oil (not just the Semi-Synthetic Stuff). Ramey of Ron Woods racing has previously observed that with e.g. Redline FULLY Synthetic Oil people with Clutch Shifting Problems went away happy. I can’t say THIS will fix your problem, but try it first. You should be using Fully Synthetic after 6000 miles anyway, to protect your engine after the break-in period.
What Tools will you need ?
- Will you need any Special Tools.? No, actually most of the tools for removing the Tank and the LHS Engine Cover are in the little tool-kit under your seat.
- You will need a Torque wrench to Torque the Clutch Spring Bolts and Engine Cover back up though, with the appropriate sockets. See The Torque Table for a list of Torque values.
- You will need a little patience.
21 21 2 343 464 - Set of Springs and Clutch Plates. Your NORMALLY only Need the FIBRE Discs, Not the steel ones!
NOTE: Check these numbers (Which MAY depend on the YEAR of your BIKE with your Dealer as the Clutch WAS modified earlier on. You should replace the springs with the disks!
11 14 2 343 240 - O-Ring for Coolant Draining Screw.
11 14 2 343 038 - Gear Shifter Seal, Recommended. (Can be bought in any Seal & Bearing Shop).
?? - The LHS Cover Gasket. In case you do damage it removing the cover, bit if you are careful and lucky...you won't need one.
And if you WANT to (Preventative Maintenance):
If you want to do preventative maintenance change the Ball Bearing in the Middle of the clutch pressure plate. Easy & Cheap. The Bearing # is 15x32x9 (Any Bearing Shop will have one!. BMW part # 21 21 2 343 173. The Bearing Number is 6002. (Part 13 in the diagram). If you do replace this bearing, which should NEVER wear unless it is misaligned because it really doesn't get much load, be careful you properly heat the clutch basket plate it fits into AND you freeze the bearing or you will break the cast clutch basket plate, which looks like both a quite fragile and expensive item. My bearing just dropped in. Do NOT hammer this plate.
- The Part # of the longer 6" vertical shaft, that rotates, with the cable end lever spline on one end sticking out of the engine cover, and the gear (rack) teeth on the other end, is 21 21 2 343 177. See the Clutch Misc Probs FAQ for reasons why.
- Also for preventative maintenance you MAY want to change the Release Bearingin the Middle of the Clutch Basket. The Part# of the fat 3" Horizontal Rack (release bearing), pulled by the above (177) part, inside the engine at the end of the clutch basket, that actually pulls/loosens the clutch late pack, is 21 21 2 343 175. See the Clutch Misc Probs FAQ for reasons why. Clutch Release Bearing: Part 14 in the diagram. Essentially the RACK discussed above.
- ONLY if you have to do the Clutch Releaser Arm Shaft Bearings (Major PITA) also check the Part Numbers FAQ.
- You MAY want to consider replacing the six screws at the springs. There is ONE case of the head of a screw being sheared off, although this is NOT common. The Torque is only 10Nm, so it should NOT happen. (See Should I replace the 6 Screws below).
I’m very much of preventative maintenance person and seals are cheap. I would highly recommend, while you’re in there, to replace the Gear Shifter Seal and the Clutch Shaft Seal (Photo shows location only). The seal sizes are Gear Shifter Seal 12x28x7mm, Clutch (Actuator) Pinion 12x18x4.5mm. They didn't have a 12x8x4.5mm for the Clutch Shaft Seal so they gave me a 12x18x5mm (But half a millimetre thicker works just fine). If it was one of the diameters it would be a problem.
So what’s the Procedure?
You may wish to consider doing this concurrently with an oil change,
i.) Drain your Engine Oil.
1. See here for the Oil Change FAQ. You should do this first and leave it awhile to cool, because you will want to do this with the engine HOT to Drain the Oil properly, however you don’t want to be taking the Engine Cover off while Hot. Btw, just do the first part of an oil change, i.e. only DRAIN the OIL, do not refill it until after the Clutch Plate Replacement.
2. Flash #412 notes. "I didn't want to drain the whole mess, so I only pulled the bottom drain plug after letting the bike sit overnight. Not very much came out. I put a BUNCH of newspaper under the work area, but it didn't lose very much more oil while I was working on it. I drained the oil into a clean container and then poured it back in when I was finished. What I am saying is that if you are doing this PREVENTATIVELY, you do not need to drain out ALL of the oil, just the sump.". So if you just changed your oil, you can just drain the sump.
ii.) Remove the Fuel Tank.
1. You need to do this to get access to the radiator. See the Gas-Tank Removal + Replacement FAQ for details. One guy tried (and managed) to refill the Coolant without removing the Gas-Tank, but even he doesn’t recommend it. See the Coolant Change FAQ if you really want to know how he did it.
iii.) Drain the Coolant
1. Check the Radiator Cap for grunge and clean it.
2. Locate the water pump cover which is on the left side of the engine towards the front.
3. Remove the lower of the three Allen bolts and have a bucket ready. Put your bike on its side stand to empty some more coolant. Remove the remaining 2 bolts on the Water-pump cover. There is NO NEED to remove coolant hoses off the impeller housing to do a water pump seal replacement, just roll the housing, hoses still connected, up and out of your way, with string if necessary. If you do decide to replace the clamps, get some of these: New Clamps. Here's shot of the old and new clamps.
iv.) Remove the LHS Engine Cover
1. Remove the two bolts holding the starter to the LHS Engine Cover and let it hang. Marty #436 provided this great annotated Photo of the Cover.
2. Remove your Gear Shifter. All it takes is undoing the Allen Bolt and wiggling it off the spline. Note the position first and if you haven’t moved it down one notch, now’s a good time to consider it. See the Gear Shifting FAQ.
3. Remove the Clutch Cable off the Fork Lever on top of the LHS Engine Cover. This entails loosening the clutch cable at your Clutch Lever on the handlebars, so there is enough play to get the cable off the Fork Lever. Flash #412 notes "You don't NEED to slack the cable adjustment at the grip. What I do is pull in the clutch lever with my left hand and grab the cable sheath down at the bottom with my right hand. As I let off the lever with my left, I pull the sheath with my right, getting enough slack down there to slip the cable out of the slot. (Putting it back together generally requires slack, however.)". NOTE! "How do you get the actuator arm off of the splines without hurting anything. The Clymer just says remove the bolt and remove the arm. I'd hate to apply to much force and damage something." Basically it's a B**** to get off if the bolt has been tightened even close to the right torque, or over it. I ended up spreading the thing with a screwdriver in the slot and a bit of LIGHT GENTLE twist. Heed the advice about NOT overtightening when it goes back on.
Tap a small (pocket-sized) screwdriver into the expansion slot (but NOT into the casing) enough to open it up. Just a little bit will be enough to get it off. Too much will break the lever (you have been warned).
4. Get a Pencil or Magic Marker to mark the position of the Clutch Fork with respect to the Engine Cover, for when you re-install it.
5. Remove the engine cover (Allen) bolts and note the location of each bolt. (some are different lengths, but most are the same length).
6. Gently coax the engine cover off and watch out you do not damage the Shift Lever Seal on the spline, if you are not going to replace it. Watch how much the Clutch Fork Rotates until the Cover is free, because this will help you set it to the right position when you replace it. You need to keep the whole deal straight and gently wiggle the casing. The aluminium clutch lever arm rotates clockwise, which should roll the shaft teeth off the Clutch Release Bearing Rack. Be gentle and take your time, keep the casing straight or the casing locating pins, the release bearing and the impeller Drive Gear all conspire to jam you in. For details of what I am referring to when I talk of the Clutch Release Bearing see the Clutch Cover Removal FAQ.
7. In addition, the paper gasket on the casing is very fragile and rips easily. So, avoid curling your fingers around the inside. If you rip the gasket, you will have to buy or make a new one out of gasket paper.
8. Now you’ll see the innards.
v.) Remove the Clutch Springs & Plates
1. Now you have to remove the 6 bolts (with the spring behind them) from the clutch pressure plate and ease the pressure plate off. Don’t lose the washers and don’t get the New and Old Springs mixed up. The BMW Manual recommends replacement of the Fibre Plates and the Springs simultaneously.
2. Ease out the Clutch Stack (Fibre Discs and Smooth Metal Discs are interleaved) AS A WHOLE UNIT. You can take them out individually if you wish, but remember the order and the orientation. A magic marker across the tabs helps with the orientation to each other. "
3. Don’t forget to remember the order in which the clutch discs and the metal discs are in.! . Before disassembling the clutch (just 4 or 5 screws with springs behind them) take a look at the discs in order to see the sequence and the surface the discs are inserted. (You can insert them "the wrong way", so take a close look)."
4. Keeping the Smooth Discs in the same order they came out, and keeping the tabs lined up in the order they came out, check them for wear and for true.
5. Soak your fibre discs in oil prior to installation so the don’t rip to shreds when you first use the clutch.
6. If the Smooth Metal Discs are OK, interleave the new Fibre Discs between the old smooth discs and replace them into the Clutch Basket. Make sure the last fibre disk is set into the slots in the "basket", offset from the rest of the discs. Note that this is dependent on the YEAR of your Classic however as the Clutch was changed in about '95 or '96.
7. Now is a good time to check the condition of your clutch release bearing (The RACK in the middle of the pressure plate) and of its mate, the Clutch Spindle, because if they are failing they will could soon look like this. (refer the Stiffer Clutch Springs FAQ for more information).
8. Before you replace the pressure plate, check the bearing on the inside for wear. i.e. feel if the bearings are crunchy or the bearings wobbly.
9. Replace the Pressure Plate, then install springs, washers and bolts in that order, doing each up as far possible by hand first. Torque them up the working with pairs of bolts across the diagonals. The specified Torque is 10Nm.
vi.) Replace the Gear Shift Seal (and Clutch Spindle Seal if so required)
1. Gear Shift Seal: Just pull out the old one with a screwdriver or better a stiff plastic rod, taking care NOT to scratch the metal surface, grease the new seal and push it into place. The writing on the seal faces outwards, in case you forget.
2. Clutch Shifting Shaft Seal: Either you can either try to prise the old one out with the Clutch Shifting Shaft in place and fit the new one over the top, or you will need to remove the E-Clip inside the casing, just under the seal, pull the Clutch Actuator Arm out, replace the Seal (which is easier to get out this way) and then replace the Clutch Actuator Arm and E-Clip. Have a look at the Clutch Cover Removal FAQ for more details.
vii.) Replace the LHS Engine Cover
Note: The Clymer Manual says something about Bleeding the Oil System.
1. Putting the casing back on is a harmonic convergence of drive gear, shift lever and clutch arm and bolt alignment. If you noted how much the Clutch Arm turned when you took the cover off, you will have a good idea of its starting position when you replace the cover. It should start from about 3-4pm (facing the LHS of the bike) and turn anticlockwise back to its original position as you push the cover on.
2. The Clutch release bearing (Flat Rack with Teeth, Bottom of Picture) that sticks out of the centre of the clutch pack always wants to rotate with the Flat Side UP, (Note Clutch springs are off in this Photo, but will be in place if you just do the water pump) because of the weight distribution. It keeps rotating until the Teeth face about 5 o'clock, making it impossible to get the cover back on. To get it into the Clutch Cover the Rack must be horizontal, with the Teeth facing towards the rear of the bike so that it will properly mate with the clutch shaft. You can get around this by taking a pea-sized dollop of generic grease (not hi-temp) and putting it between the rack and clutch pack to keep the rack from rotating. THEN the cover should go right on.
3. Eyeball your shift gear on the plate and the internal gear and push lightly. You may need to gently rotate the impeller to allow the drive gear to mate with what drive sit. YOU WILL KNOW if its set in right because the plate moves in quite a bit when correct. Otherwise, you're just jamming. Again, watch your paper gasket. You will tend to gravitate towards grabbing it with your fingers and ripping it. BE PATIENT when putting the engine cover back on and watch out for proper alignment of the Shift Lever Shaft and the Clutch Release Shaft.
4. Do up your Case-Bolts to Torque Specs.
5. Do up your Starter Motor to Case Bolts to Torque Specs.
6. Replace the Gear Shifter Lever on the Spline. Make sure it line up with your earlier marks. You might like to consider moving it down a notch at this stage. See the Gear Shifting FAQ for details.
7. Replace the Clutch Cable in the Aluminium Fork (Note mine is cracked in this photo) and re-attach the cable at your handlebars. Adjust to the recommended Free-Play at the Clutch Lever on the handlebars. Do NOT overtighten!
8. Check the Large O-Ring behind the Water Pump Impeller Cover and if required replace it, first cleaning the groove it was in. If required, replace it with a new O-Ring, return it to it’s location against the LHS Engine Cover and replace the 3 Allen key Bolts, torquing to spec. Note the crush washer on the lower (drain) bolt should be changed, but you can re-use it once at a pinch. The bolt also requires Loctite.
viii.) Replace Fluids
1. For Coolant replacement refer to the Coolant Change FAQ.
2. For Oil replacement refer to the Oil Change FAQ. It might be a good time to change your Oil & Oil Filter too, depending on the state of your Oil since you noticed the Water Pump had failed.
ix.) Replace the Tank
1. For Tank Replacement refer to the Gas-Tank Removal + Replacement FAQ.
That’s it. Go out for a ride.! Hombre sin Nombre
Cheers & Rgds, Kristian
by Kristian #562. Refer the Stiffer Clutch Springs FAQ & Clutch Cover Removal FAQfor details of my Clutch Problems.
The first set that failed. The second set that failed.
F650 1998 with slipping clutch. Two different dealers said, that clutch is NOT slipping and everything is normal. So I made no changes. F650 GS 2000 with a lot of slipping. So I changed to stiffer springs from Team-Pami. Then the clutch cable broke twice and lately some parts of the clutch (The Rack & Pinion (ed.)) broke the same way as Kristian described it. Now I have the OEM parts again and there is slight slipping. Maybe I will use a different oil. We will see. by Robert #1071.
I was attending the European Riders Rally in Burkesville, KY riding on one of the guided tours (paved road, hills, curves). My wife was on the bike with me, luggage was removed. Very early on in the ride I noticed the clutch felt strange. At the first stop, I asked Merrill, my brother, to check it. He thought it was "about gone" and we adjusted the cable to take up the slack in order to nurse it back to the campsite and then home. When I got it home and removed the side cover I noticed the busted tooth on the rack and deduced that the pinion slipped over a tooth, causing the slack in the cable and, hence, the odd feel of the clutch lever. My guess (and Merrill's) is that that particular tooth gets more stress than the others. In other words, the spring tension is strongest when that tooth is being engaged by the pinion resulting in metal fatigue. I never found the tooth or enough pieces to make a tooth. I hope it fell out in that puddle of oil when I removed the side cover. Or perhaps it will eventually get stuck to the drain plug. Anyway there it is (picture attached). Bike is a '97 ST that seldom sees dirt except for campground roads and my driveway. Mostly ridden on two lanes at about 60 mph if I can. 28,000 miles, stock clutch springs. I estimate that, with the wife and luggage that weekend, we had almost 400 lbs on the bike, so we had it maxed out. Hope this helps someone. by Raleigh
Hi, I have a 1998 F650 Funduro and my clutch seems to have broke, at first I thought it was just the cable but the cable is still intact. Before it got broke, it started emitting some whistling and mechanical noises and soon after it lost it's tension and the lever went loose, I also noticed that the lever on the clutch compartment is stuck, or rather, there is no force pulling it back again like before. I am not familiar with clutches but I hunch it's some sort of spring or something like that. The engine still runs fine. It was the ball bearing! I managed to find what went wrong. Thanks for your precious help guys. I have drained the oil already as I don't mind an early oil change since I use it everyday. I noticed there were a lot of iron filings on the sump plug's magnet, almost full actually, much more than ever before. I don't think it's too bad since they're all very small fragments but it's a bit too much in my opinion. I wish you could post your views on this matter. I can't lift up the actuating arm, actually I can hardly push it back and forth, it seems to be jammed really, however, if this helps, I can still change gears and the engine runs perfectly as before, matter of fact, I managed to keep riding all the way to my garage when the clutch broke, as I initially thought it was just the cable and the gears still work on low revs. I have never experienced any slipping whatsoever, except on those few minutes before it went. when I actually manage to pull the clutch arm forth, I am able to reproduce the whistling noise I described before. Found it.! It was the ball bearing on the clutch sprocket that had worn out. This explains the excess iron filings on the sump plug as well as the 'whistling' noises which as I had hunched, was the sound of a loose ball bearing spinning around while the clutch was actuated. I shall be sending in the photos along with my membership to support this great site! Thanks again all of you for finding the time and good will to help me out. Later on today I shall pay a visit to the bloodsucking dealer over here in order to try and purchase a replacement part. This reminds me, is it right for them to charge me the equivalent of US $30 for a clutch cable which I used to get for just US $7 for my Yamaha? My clutch release bearing, (part number 14 in the diagram) has been literally crushed to pieces after just 2 years, I managed to get the replacement free of charge but I need to know how difficult it is to replace it and what special tools (if any) are required for the job and what to keep in mind and be ready for. MarconeNRK (Mark Bishop, Isle of Malta.)
I was even thinking to send you a digital picture with my rack, that looks EXACTLY like Raleigh's one. I was luckier in finding the missing teeth still stuck in the pinion. I have seen a dozen of times the rusted, stripped rack, discussed in relation to the stiffer springs though. gim (orange '97ST)
Clutch wont fully engage: '99 f650 w/26K miles. Last night, all of a sudden, my clutch started behaving strangely. it won't engage completely and will slip at 50%+ throttle. it's as if something internal is keeping the release mechanism from "un-releasing" completely. so externally, the cable fork stops before it should. Now there is slack in the cable so the hand lever has about 3/4 inch free play. clutch operation is otherwise fine. it completely disengages, shifts well, and starts to engage fine. and riding gingerly, it got me the 20 miles home from work. but twist the throttle and it slips. As I said this didn't come on slowly. It's not like clutch wear. it was an instantaneous change in the way the clutch engaged that I could obviously feel at the lever since it was no longer getting pulled all the way back to normal position. Well, I found the problem. Same as a problem mentioned in the FAQs. A tooth on the release head broke and got wedged between the splines on the release shaft (bending one of them). so both have to be replaced. off to call the dealer. although I have a new gasket, I'm reusing the old one. it's in great shape and quite new since I replaced it when I replaced my water pump a few K miles ago (so I won't be replacing the pump now). by the way, I almost went crazy trying to get the clutch cover off. I KNEW I'd taken all the bolts out, but it wouldn't budge. I beat on it with a rubber mallet...nothing. turns out, the broken tooth on the release head (which was still attached by a metal hair) had wedged into the splines on the release shaft, and was keeping the thing from rotating and releasing the side cover. only when I turned the release shaft (clockwise) with some pliers did the cover come right off. Mark #403
Replace the BEARING in the Clutch Basket FRONT Plate, I have a post of one that went toasty, MarconeRK in Malta's whined itself to Death. Cheap (from any Bearing House, not BMW) and Cheerful and easy to get out with Gentle heat. WATCH it carefully, it is CAST, and if it cools too quick/you hit it or drop it it will BREAK. See mine (Unbroken in the FAQs). Replace the little seal around the Shaft, MUCH easier off than with it on, although possible ( I did it on my almost NEW GS with it on). Also Cheap. Get a new circlip for the Actuator Shaft maybe, and a new circlip and 2 new ones of those Springy Washers behind the Rack if they're weak. All cheap peace-of-mind parts. That's it. Oh and CHECK the two small bearings each end of that shaft, they are are REAL PITA to replace, but mine were toast because the little bits of rack/spline got in there and munched them up. You can only really check it with a NEW shaft. Check it goes round OK. Also check that the bits didn't munch the soft alu casting where the rack slides in/out in the Clutch Cover plate or it may Jam. And CLEAN all the places in the bearing well of all the little rack bits CAREFULLY. Kristian#562
Clutch Plate Problems/Replacement
The friction plates cost 17.50 each. There is no need to replace the metal plates unless they are damaged. There is a clutch kit that includes the 7 friction disks and 6 springs for 100.00 dollars. This is the way to go. You should replace the springs with the disks. My springs were at or 1mm below the minimum and 10k later I replaced the clutch again. The new springs were 1.5mm longer than the used ones. I guess this is enough to make a difference. At 73000 miles my bearings and cams are in perfect shape so I did not change them. I plan to replace them next winter at around 90000 miles. I don't have the part number handy for the kit but it was listed on BMWs parts fiche with the clutch stuff. Steve#417(in,us).
Q. The question is, how many miles before I should be going inside the left cover to measure the clutch stack? What mileage can I expect from the OE plates? Has any one gone inside, measured and decided not to change? If so was the wear rate linear?. If its going to last to 30000 miles, that's all next year, so sure it'll stay where it is. If its going to go at 20000 it wants replacing now while I have the time and cash and space to work. I'm just trying to avoid going to Morocco two days out of the work shop or worse still two days before needing to go into the shop!
I have got 30,000 miles on my bike and my original clutch is still clutching. Why go looking for trouble? My motto is if it is still working, don't check it, you will just see something that will worry you. (My R65LS had 62,000 miles on it when my dealer told me that the clutch was only 50% and I should install a new one. So I did - and ended up selling the bike 6 months later.) The only thing I check for wear are my brakes and tires. Not being able to go is one thing, not being able to stop is another. Like all things that wear, it really depends upon how you use the clutch. In my experience, wet clutches can last 100,000 miles if you don't slip them much when taking off from a stop or if you do a lot of long-distant traveling and rarely use the clutch except to shift. However, if you like to slip clutches for fun, are a motorcycle courier, motorcycle magazine tester or extreme-sports exhibitionist, a clutch might only last 10,000 miles. I guess you just have to flip a coin. However, I think if I was taking a long trip like you plan to do and intended to go to the effort of taking the clutch apart to measure the plates, I would just plan on buying new plates and replace them while under the clutch cover. If you really want to measure them, no doubt the maintenance manual has thickness wear limits, but I don't have a clue if the wear on a clutch is linear, so I don't know how much knowing the thickness of the plates is going to help you. Richard #230
I'm at 25K miles, and not a hint of trouble. Never measured. I'm sure others here have gone much farther. Raymo #1173, Chicago, 2001 F650GSA
I have 27K on the stock clutch so far. If you're really curious, take a look at 20K when you should preventatively check (replace?) the stock water pump seals/shaft. Marty #436-Chicago-97 F650F
Should I replace the 6 Screws?
Anyone recommend a specification and source for screws that are not made of sponge metal? I need the name of the metal or process or whatever, since I don't know the terminology and can't search without a such a spec. The screw says 8.8 on the head, and the manufacturer's initials are in Cyrillic, which probably explains the garbage metal. I want those black ones, like at the cam carrier, supposed to be stronger. I was putting my clutch plate back on after replacing the clutch rack thingy (which also seems to be rather weak metal), broken spline at 11000km), and I spun the head off one of the six spring screws, before 10NM, not enough torque to break a toothpick! I do recommend that anyone who goes in there replaces the screws at the same time. BTW, should I be okay to ride for a week or two with only five springs? Aleksander in Dubai 98ST
Normal Bolts come in two flavours, Grade 8.8 (450MPa) are High Tensile Bolts, Grade 4.6 (195MPa) according to my Steel Designer Manual are lower strength. (ah the Joys of being a Civil Engineer) These bolts only really need to be nipped up against the spring, not massively torqued, boy you must have got a REAL Dud if you managed to kill that one, or cross threaded it or something. I hope you haven't damaged the MUCH SOFTER Aluminium basket that it goes into, THAT would be a major $$ PITA. I shouldn't imagine 5 bolts will be too much of a problem for a week, but ANY decent hardware shop should have a bolt that will fit, today. Kristian#562 HK ex'96F, '00 GS
You MAY want to replace the six screws at the springs. You'll have to take them off to replace the bearing release thingy that you broke, and they are not re-useable or replaceable with ordinary screws (well, you can use ordinary screws, but you probably shouldn't), since they're stretch screws. I recently spun the head off one while reusing them, and faced a huge hassle getting the stud out, needing to completely disassembly the clutch. The procedure is easy and even fun, so go ahead as Kristian says and do it yourself. Only other consideration is that you might want to have a new LHS cover gasket on hand, in case you tear the old one. As part of my follow-up research on getting better screws for the clutch plate (the six that hold the springs; one of mine lost its head), I got the following reply from Motorworks:
...The problem is these are stretch bolts, designed to distort when correctly torqued ( 10NM ), and so resist working loose in operation.
But if re-used they will not work properly, and possibly shear. We do sell Allen socket driven, M6 black clutch bolts for the K's and 8valve R's, but these are again stretch bolts and not designed for reuse. CLA54417 55p each p57, but would recommend staying with original.
So, if you're going in there, get new screws first. You're right that the stretchy screws are not mentioned in Clymer (or the FAQ), but Clymer does say replace the springs if they're below wear limit (p177). But here's another Clymer typo: the service limit of the clutch plate stack cannot be 35.0mm. It's only that size if you insert the friction plates (p182). Aleksander in Dubai 98ST
Very interesting! Thanks for sharing those comments, especially in their original form. Both the Classic and GS Service manuals specify that new clutch springs are to be used every time the clutch is serviced, but make no mention of replacing the bolts. The Clymer mentions replacing neither springs or bolts. And as far as I can tell, there are no special footnotes on those parts in the parts information available to me. But Motorworks has great F650 experience and knows a lot about F650 parts that we have never heard before. Todd #389
I've had mine apart three times and never replaced the clutch screws. I never heard of bolts that stretch at 10 Nm torque. Flash 412 (CO)
No I also didn't replace the Clutch Screws, even though I had them on and off twice. Mine was '96, Flash's a '97 and Alexander's a '95 I think. I appreciate what Flash is saying and 10Nm is PEANUTS but still for the Money and from the info Alex got previously, I think you can probably replace them for peace of mind, with some decent bolts from your friendly hardware store.
Kristian, did you (or anyone else) replace the spring screws? I'm not planning to replace them. they came out easily, and I can't imagine that at 10nm, ANYTHING will happen to them. while I was in there, I measured my friction plates and springs and everything is JUST passable, according to the limits stated in the Clymer manual (haven't cross-checked the BMW manual). So, I figured I'd be replacing all the clutch plates and springs within the next 5-10K miles anyway. replacing those should be a snap. but I'm wondering if anything else should be replaced while I'm at it? like bearings....? that would make it a more complicated job, but hey, anything's possible...right? anything else that ought to be replaced? Mark #403
Many Thanks to HsN and Flash #412.
Removing the NUT holding the Clutch Basket on
by Flash#412, Kristian #562
The Problem: I finally got the parts, courage and weather to pull my motor (need to replace a shift fork). The clutch basket nut will not come off, by the way mine is a 27mm. I was going to take a propane torch to it but couldn't find it (the torch). I figure if I carefully heat the nut it will come loose. It is really on there I was standing on the rear brake and turning the socket wrench and I could hear and feel the wheel slip. I only weigh 260 pounds, maybe that is not enough pressure on the brake. I also took a hammer and drift and tapped the nut all the way around and the thing just won't let go. Will I do any damage if the trans rotates the wrong way while I try to loosen this thing? His Answer: I finally got back to my clutch nut. I bought an impact wrench and a Mapp gas torch. I also fabricated an iron ring with some angle iron to put pressure on the clutch basket while locking the TDC bolt in place. After heating it up it spun right off. Now its back to the transmission. XtreemLEE
Lots of Heat, A long BREAKER Bar, lot of brake resistance and a little help from the TDC Bolt (You did put it in right?) will go a long way. Don't try and undo it straight off the TDC bolt w/o heat and brakes, that little head isn't very big. Apparently Motion Pro make a Clutch Basket Holder, for just this sort of thing (mentioned in the Clymer manual).
Here's some Pic's of the Motion Pro Tool: available at www.denniskirk.com
Basically, USE the TDC bolt to help you. This excerpt is specifically for the Flywheel BUT it is a similar Problem, just on the other side of the Crankshaft. With regards to having the TDC bolt in place when you undo the Flywheel Nut, you have a gearing disadvantage on the bolt by whatever gear you have it in when you go to loosen the countershaft nut. You have a disadvantage of only the primary drive when you go to loosen the Clutch Basket Nut. The alternator nut is ON THE CRANK and you are reefing right on the bolt. But... what're you gonna do? You HAVE to hold the crank somehow. Putting the Clutch Back together is one option.
An impact wrench on the rotor nut against the TDC bolt is the only other one I can think of .
Take one pressure plate and one friction plate from the clutch pack. Drill several holes through both of them. Rivet them together with about six or ten steel rivets. By God THAT will lock the clutch so it won't spin. Then you can use the TDC bolt, the brakes, a long breaker bar, heat, cussing and everything else. The clutch is not disengaged if you have one friction plate and one pressure plate locked together.
Q. Putting it in gear didn't seem to help?
A. Not if you don't have the clutch pack in place.
Q. Will heat hurt anything other than that O-ring you say is in there?
A. Not if you don't go crazy. There are a couple of plastic gears on the oil pump drives behind the clutch basket though.
Q. The pressure plate locks on the shaft and the friction plate locks to the outside of the basket therefore it wouldn't move when trying to turn the nut other than tearing the rivets out? Sounds like a tool to be made?
A. You can also buy one at many motorcycle accessory stores. Take a pair of clutch plates with you to be sure to get the right one.
Q. Yeah steel rivets not pop rivets, hmmmmm how much is a friction and a pressure plate?
A. LOTS cheaper than letting the dealer do the job.
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