Clutch adjustment (slipping and lost neural - Triumph Forum: Triumph Rat Motorcycle Forums
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post #1 of 23 (permalink) Old 06-22-2019, 07:41 AM Thread Starter
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Main Motorcycle: Triumph Bonneville T140E
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Clutch adjustment (slipping and lost neural

Hi all,

When my T140 Bonnie is warm, it is next to impossible to get neutral with the engine running but easy with the motor off. I have been researching and read that this might be a clutch adjustment. Also, under full throttle at higher speeds the clutch does slip a little but it is a relatively new and uprated clutch to suit the higher power or the bike.

So, it definitely needs some adjustment. Any words of advice and tips on the best way to do this please?

Cheers,
Ian
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post #2 of 23 (permalink) Old 06-22-2019, 10:10 AM
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You need to have clearance on the clutch pushrod. That is adjustable with the locknut and centre screw on the outside plate on your clutch basket. You need to back that inside screw a small amount so when you press your clutch lever there's a small amount of play before the basket gets expanded.
You also need to make sure the screws that hold the clutch together have enough pressure on them to prevent slippage. This adjustment has to be done first.
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post #3 of 23 (permalink) Old 06-22-2019, 11:13 AM
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It sounds like you need to true the pressure plate. This is done with the primary cover off. A wobbly pressure plate can cause both issues. Sight down on the pressure plate with the clutch lever pulled in will spinning over the clutch (kicker). Adjust the clutch springs until the gap between pressure plate and first clutch plate is uniform. The adjust the pushrod free-play.
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post #4 of 23 (permalink) Old 06-22-2019, 01:12 PM
wol
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have you got a workshop manual ? -- even a Haynes gives an easy to follow instruction on how to set up and adjust the clutch
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post #5 of 23 (permalink) Old 06-22-2019, 04:12 PM
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Hi Ian,
As this bike is new to you, you don’t yet know the condition of the components fitted. My advice is that you strip the clutch and inspect it rather than adjust it, if all is well inside, then the cost is only a primary case gasket—but at least you will know.
I would expect that you already have a 7 plate conversion fitted by the Previous Owner, he has made so many other sensible and expensive modifications, I expect he will have done this already, as it is probably the best 100 you can spend on a Triumph twin.

To strip inspect, reassemble and adjust:
1) With the bike in 5th gear, disconnect the clutch cable at the handlebar lever, this is the first thing to disconnect , and the last to reconnect. (Unless you have a hydraulic conversion)
2) Drain primary oil, remove LH footpeg and gearlever, remove primary cover—newspaper on the ground helps soak up oil drips.
3) If you have belt drive, you are likely to have a different clutch, if you have a primary chain then you are likely to have a standard clutch with uprated components.
4) Slacken the central locknut 1/2 a turn in preparation for later adjustment. Remove the 3 load springs using a special Triumph tool or a modified screwdriver, take off the clutch pressure plate. Pull out the pushrod and check for damage (using a magnet helps)
5) Remove the clutch drive and plain plates one by one, you will need to wiggle them past the gear selector. Hooks and magnets help. If you put the bike on the sidestand Issac Newton will assist also.
6) Inspect all of the plates for flatness, placing them on a sheet of plate glass helps you spot warpage, and all of the tangs for burrs (dress any burrs with a file if necessary)
At this point you will need to decide if the plates are serviceable or need replacement.
7) check carefully the clutch drum for wear and notches where the clutch drive plate tangs locate. Check carefully where the plain plate tangs locate in the clutch hub for wear and notches. These should be smooth.
If there is a small amount of damage, then the worn faces can be dressed with a file or on a mill, if they are badly worn (notched) then replacement is needed. If you file the faces manually, be aware that the distances between the faces are critical for an even drive through the clutch, they need to be filed by an even amount.
8) Look at the plate at the centre of the clutch hub, if there is black gunge oozing out of it, then it is likely the cush drive in the hub has failed and needs replacement. If you grab the hub and turn it backwards and forwards hard (there is a tool you can buy or make), you might feel some free play if it failed badly (do not confuse this with gearbox backlash). Holding the rear brake on helps.
If you suspect the cush drive is weak or failed, replace the cush drive rubbers.

9) Behind the clutch there are 20 loose roller bearings and a thrust washer, you will need to decide if you want to inspect these. The rollers do not give trouble, but the thrust washer can wear badly. Inspecting them requires a lot more work. Locking the clutch, removing the centre hub nut, using a special puller to break the taper lock of the clutch on the gearbox mainshaft, removing the alternator and drawing off the clutch, primary chain and gearchange shaft as one unit. You then have to press the clutch central boss off of the hub. The rollers and thrust washer are then visible. Replace as necessary. (Request in another post reassembly procedure)

10) If you did not remove the hub (or now have it refitted) it is time to reassemble. The clutch.

11) Put the bike back on the centre stand. Clean the plates and refit the plates one by one, starting with a drive plate, until all plates are fitted. If you have 7 drive plates you are lucky, if you have 6 drive plates seriously consider buying a 7 plate conversion as you are already experiencing clutch drag.

12) When the last plain plate is in put the pushrod back in, refit the pressure plate and springs, wind the springs down evenly with the adjuster nuts, the nuts should be flush with the pressure plate.

13) The next stage is crucial to prevent clutch drag; screw in the central pushrod adjuster screw until all free play is removed, then keep screwing it in until the pressure plate has been lifted completely clear of the drive plates.
Make up a pointer so that it’s tip is close to the pressure plate (a coathanger or piece of wire will do). Spin the rear wheel slowly, if you observe any wobble on the pressure plate as it turns, you must adjust the tension of the springs accordingly to balance them out. Take care to get the tension balanced so there is no visible wobble on the plate.

12) Once you are happy with the plate setup, screw out the central pushrod adjuster until the pressure plate is in full contact with the drive plates. You will now need to set the pushrod clearance, finding the contact point can be hard, screw out the adjuster so you definitely have clearance. Very delicately with thumb and forefinger only screw in the adjuster so it contacts the pushrod, you might need to go in and out several times to feel the contact point, it is a slight change in pressure on the screwdriver that can be hard to determine. Once you have found the contact point turn the adjuster back 1/2 turn and tighten the locknut.

13) refit the primary cover plate, gearlever, footpeg and click the bike through the gearbox to neutral (turning the rear wheel helps).

14) Through the top inspection cap pour in 100-150cc of the oil you used for the engine.

15) refit the cable at the handlebar end, adjust so you have a tiny amount of free play, with the bars tuned from lock to lock.

16) Go for a ride, seeking out as many red traffic lights as possible.

17) If the clutch still slips, try tightening the springs 1 complete turn (unfortunately this requires cover removal and wobble adjustment). If it still slips, replace the springs (again requires cover removal and ‘wobble’ adjustment)

(I have not covered adjusting the primary chain here, but while the cover is off it is a good idea to do so)

Good Luck
Regards
Peg.
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Last edited by Rancidpegwoman; 06-22-2019 at 07:02 PM.
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post #6 of 23 (permalink) Old 06-24-2019, 03:15 AM Thread Starter
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Thanks so much all, especially Peg for that great write-up!

I have one quick question: how do I judge the correct amount or pressure to set the springs? Is it simply a matter of screwing them in to make them flush with the plate, adjust for wobble and go for a ride to see if the clutch slips?
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post #7 of 23 (permalink) Old 06-24-2019, 07:00 AM
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Quote:
Originally Posted by Boggie View Post
Thanks so much all, especially Peg for that great write-up!

I have one quick question: how do I judge the correct amount or pressure to set the springs? Is it simply a matter of screwing them in to make them flush with the plate, adjust for wobble and go for a ride to see if the clutch slips?
Yes....all you can do.

Only other thing is to make sure you haven't over adjusted and the springs are binding - unlikely at flush with the PP, but can happen if you are over zealous.

tridentt150v,
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(Where women blow and men chunder).
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post #8 of 23 (permalink) Old 06-24-2019, 02:42 PM
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Quote:
Originally Posted by Boggie View Post
Thanks so much all, especially Peg for that great write-up!

I have one quick question: how do I judge the correct amount or pressure to set the springs? Is it simply a matter of screwing them in to make them flush with the plate, adjust for wobble and go for a ride to see if the clutch slips?
Hi Boggie,
Flush is an average setting that appears to be a good starting point in most cases, the 3 adjuster bolts are sized so that when the thread just pokes through the adjuster nut, the top of the nut is flush with the pressure plate.
Adjustment is a compromise between slip and a clutch lever that is hard to squeeze.
If you screw them in further, you get more clamping pressure, but a harder clutch to operate (also more clutch cable breakage), as Trident150 says you can go too far and coil bind the springs.
If you screw them out you get a nicer clutch to use but a greater chance of clutch slip.

I can see that you are a city dweller, so a heavy clutch is not desirable, however a slipping clutch will wear out very quickly. I also know that your bike Is not standard and is likely to produce more torque than standard. The flush setting is usually good for standard bikes but I thought I would not have mentioned slip if you were putting out standard power.

If you find you have the 7 plates installed, these can transmit more torque than the 6 plate. Therefore it is likely that you can use less spring pressure, have a lighter clutch action and still not get slip.
Some people have found they can fit the lighter springs from a 650cc T120 and not get slip with a 7 plate clutch in a T140, giving a nice light clutch.
It is a pita setting it up, but you 100% reap the benefits of your time taken, especially riding in the city.

Regards
Peg.

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post #9 of 23 (permalink) Old 06-24-2019, 06:07 PM Thread Starter
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Thanks Peg!

Fortunately I am not town as I am very West (and a bit North) of London in a small South Bucks village. Leafy country lanes and sweeping open roads beckon... 🙂

With the tuned engine the bike ran a 62BHP dyno plot (not sure about the torque but she pulls like a train 🙂 so even though it is the 7-plate clutch (found the receipt) it needs a little more pressure, I suspect. Which is a shame as the clutch is already erring on the weighty side.

I will have a play at the weekend and see if I can find a happy medium. If not, I might put a hydraulic clutch kit on my Christmas List....
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post #10 of 23 (permalink) Old 06-25-2019, 07:33 AM
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Hi Ian,

Quote:
Originally Posted by Boggie View Post
hydraulic clutch kit on my Christmas List....
Before you do that, might be worth checking what clutch springs are in there, and how tired, or not, they are? They vary a bit ... http://www.britbike.com/forums/ubbth...50s#Post699040.

Aiui from posts here, the 7-plate clutch is normally fitted with late 650 springs? 57-1830.

Hth.

Regards,

Stuart
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