Britbike forum Forums British Motorcycle specific Brands Triumph bulletin board Specific amount of clutch lift?

Most of the the time I cannot get the 72 to go into neutral with the motor running. How ever there have been times where it will. All else is fine. No grinding. Shifts like butter. I no longer have the back or the patience to spend hours making microscopic turns of the adjustment screw to get it right. Is there a correct amount of lift? I have a dial indicator.

I think no matter the amount of separation between the clutch plate and the pressure plate (I use about 1/8) due to I have been riding new bikes (2021 models) and many have the N problem.

The manual specifies 1/2 turn out from the point at which the pressure plate adjuster screw makes contact with the pushrod. If you're really careful to make sure you know exactly when the screw is making contact, you can use as little as 1/16 of a turn back out. When running, the clearance between the two increases, so all you need is the smallest clearance you can get, as long as it really is clear. That way you'll get absolute maximum lift.

Hi Draco, Factory gave no spec on lift that I’ve been able to find. As you think, lift is very important.

I spent a lot of time measuring lift on different bikes. Some came from factory with only .073-.085”. My ‘73 Tiger was like that. I have found .115-120 to .125” works best. Over .125 it starts doing odd things like can drag more or drag very slightly during shifting.

Lots of factors in how much lift you get. Grip thickness, lever perch type. Wear in lever fulcrum. Ball cam version. Wear in ball cam. Cable brand & how much compression in housing & stretch in cable. How much free play you have in rod adjustment, how much play you have in clutch thrust washer, spider. How much free play you have in cable.

For problem cases I’ve ground face of lever to perch so end of lever is farther from grip. I’ve modified perch in similar fashion to move lever end farther from bar. This allows lever to pull more cable.

Doing experiments I found the cam has lost motion. This is counter intuitive but backing screw out a little further like 5/8 turn compensates somewhat for lost motion. You compensate for the clearance with bar adjuster. So cam is clocked slightly further on ball ramps so they are at steeper part of ramp.

Running less cold motor cable play gives more pull. The play increases as motor is heat soaked. That is normal. But you must really pay attention play does not go to zero & give rod constant contact.

After setting rod to 5/8, the next easiest thing is modifying lever. I started out by experimenting with used levers. You can only grind so much or the lever gets too tin at cable end hole.

Grinding perch is more difficult as the alloy ones will need to be hollowed/relived near fulcrum. I used tiny burr in Dremel tool.

Lift is only one part of clutch drag. Wear in thrust washer & spider sides allows end float & wobble with lever pulled.

Of course wear in grooves of basket & drum & plate tangs makes plates not want to separate.

Often a little wear here, a little there adds up to not perfect freeing.

6 plate clutches with the full width friction pads have more drag than 7 plate with the smaller pads, even though 7 plate gives 2 more friction surfaces.

Oil type can make big difference.

Of course if wobble is way out that’s a problem. So long as lift is in the .120” range it will tolerate minor wobble no problems.

What to do? Measure lift first. You can just use depth gauge on vernier caliper through adjuster hole on primary cover. Pull lever & hold, measure. Release lever measure. Subtract difference = lift.

Often lift is good & clutch has slight drag. But overall works fine. Shifts fine. Often, if you come to standstill in 1st, you can lightly blip throttle. Just at the very cusp of rpm drop the shafts are neither accelerating or decelerating, the gear dogs are unloaded. At that very moment click into neutral. Thales some practice. Let out clutch easy to verify it’s actually in neutral.

Engine idle rpm has direct relationship with gear momentum. Slower the idle the better finding neutral works. But slow idle not good for oiling & promotes stalling.

Modern thin trans oil is slippery & allows gears to rotate freely. So in can take 4-6 seconds for them to coast to a stop even with perfect clutch.

5 speed with the steeply back cut gears hold together tightly with even slightest clutch stage.

The late extra stiff T140 gear shift centering springs help. It just feels better to my toe so I can feel neutral better.

On paper the clutch is very simple. But there’s a lot actually going on with the relationship of so many parts, plus oil differences. In real life not simple at all. But certainly we can overcome all these issues & have a clutch that works as good as it can.

Draco, try the throttle blipping on next road test. You may already be doing the blipping though.
Don

Part of the problem is my shop manual says to turn the adjustment screw one full turn out. I've now got it 1/2 turn out. Got some other things to do then a test ride. 90% chance of rain tomorrow so will probably will not happen.
I use my dial indicator to detect the pressure plate lift.
.005 then a 1/2 turn out.

Hi desco. Adjusting the rod, first thing is back off bar adjuster all the way. Turn in screw until you see & feel pressure plate lifting. Feel clutch lever. You MUST, MUST, MUST lever play with plate slightly lifted. This is where things go horribly wrong when owners have problems adjusting clutch. Not having free play when adjuster screw is zero clearance & slightly lifting pressure plate. It leads to the dreaded click! That is how they get the click, lack of cable play during rod adjustment.

If you don't have cable play.... on later bikes with threaded lower adjuster on cable, screw the adjuster deeper into trans to get some play. On earlier bikes with no lower threaded adjuster, no play you need shorter cable abutment. Not so simple on the early bikes.

If nothing else temporarily remove clutch lever. This allows the cable to slide into housing deeper. You'll have to back off rod adjuster screw to get slack to remove lever. Once lever is off, start over with rod screw. Lift pressure plate slightly. Now look at cable top end you should & will have play with no lever on cable.

Back to the rod screw. Now I back out screw until it's free. Then screw it in lightly until you feel it contact rod & rod has zero play. The screw will suddenly be hard to turn. If you go deeper it will begin to lift plate. But don't lift plat. We want rod/screw to just zero play with no lifting or starting to lift.

Now back out screw 5/8 turn. Counter hold screw & lock the nut tight. Don't let screw spin tighter when locking nut.

Now adjust cable with bar adjuster. If needed bring the lower threaded cable adjuster up if needed.

Depending on bar adjuster length, lever, perch version, you may run short of bar adjuster & need to readjust the lower end of cable. On early bikes than would mean changing abutment again. That is why removing lever is occasionally the better choice to get cable play during rod adjustment.

To be very clear, the point of lifting pressure plate slightly with rod screw, then verifying you have cable play is to fully seat the ball cam to zero. You must have cable play to achieve the zero point. Otherwise the cam is turned some amount & balls are on ramps, not at zero.

Cable play cold depends on lever/perch combination. I try to leave at least 1/64" cable play cold. More is better like 1/16-1/8". As plates wear the cable play gets less. You MUST have cable play or the rod will have pressure more or less on it. This causes the ends of rod to overheat. Melts ends of rod, the pressure pad in cam, the adjuster screw, & melts/wears mail shaft rod bushing. There is never ever an excuse other than neglect or lack of knowledge for an overheated rod. AT THE SAME TIME!! if you fail to keep eye on rod adjustment the rod can have zero play while the lever has plenty of free play.

So there is 2 things to keep an eye on. The rod & lever play. I've found if you check rod adjustment every 1500 mile oil change that is enough unless you racing or have clutch slippage. The cable adjustment you feel every time you free clutch at cold start.

Keep in mind the lever gets more play hot as things expand. So if you tighten cable hot, where will it be cold? If you need more lift hot which very well could be (you've already set rod perfectly), Then it's time to look at modifying lever or perch to get more cable travel. My bike I needed to do that. Smoking hot in stop/go traffic 110f day my clutch would not release. Cable play had to be taken out in that heat. Then next morning I had tension on cable, not just tiny free play, but cable was actually being pulled.

That's what prompted me to modify the used donor lever. It worked perfectly. I ultimately modified donor perch & reinstalled original level. That is what my bike current is using to very good results.

Takes some time & effort to set the clutch system. But once it's done it's really nice operation. Seems the '70 & older had less problems with release. On paper the alloy perch should pull same amount of cable, but I've found them to not do that sometimes. For whatever reason. So I've gotten to look at every bike in it's own right. I don't jump to conclusions, but start with rod adjustment first, then move on.

Wear in cam on higher milage bikes is common. The ball ramp flattens. The pivot hole can wear so when operating lever is pulled by cable the rotating cam moves sideways a little give lost motion, worn ramps & balls give less lift for a given rotation. Rust & ramp/ball wear is the main problems I've observed.

I know it's cheating by modifying bar lever can overcome cam wear & some other wear problems to a degree until wear is too great. Maybe get another 10-15+k miles on current parts. Wear in fulcrum hole in lever often results in lost motion of cable.

That's my experience. Of course all worn parts should promptly be replaced. Going through full primary overhaul is about $700+. Not chump change for most of us. So you can often make do with very good results with some thoughtful work.
Don

Hi All, Tip. Sometimes when rod is adjusted a few times without full cable free play the cam will rotate so far balls run out of their detents. This is what makes the click. However.... I've personally seen this where the cam pressure pin/cotter pin/ washer get pressed out of shape slightly & it no longer clicks at all....

Then one more miss adjustment, then a nice long ride. You pull lever good & hard & the lever just goes limp like a broken cable & clutch is released. Cable is not broken, but balls are fully out of detents such the pressure plate tension cannot turn cam back to home position.

Generally this only happens when far from home. Cure is to reach into trans filler hole & pry lever down with a screwdriver. I've had to do this on occasion on group rides. The owner didn't understand about cable free play. Once taught correct adjustment they do good there after.

The cable free play is of great importance when adjusting rod.

If clutch drags after perfect rod & cable adjustment, then you have problems in the clutch unit itself.

Too tight clutch spring adjustment will not cause drag until so tight you have spring binding. But you should have already verified you have good lift. Spring binding you'll have low lift & bar lever will feel like cable is hitting something & wants to stop.

Also especially on T140. verify the adjuster screw is not hitting inside of inspection plug. Lift will measure fine. But installing inspection plug lift is restricted. Cut slotted end of screw shorter as needed to have clearance & a little wiggle room. Recut screwdriver slot after shortening with hack saw.

Of course my screw hit the plug. I shortened it years ago. It will wear right through plug if hitting & not shortened. I've seen that a few times.
Don

In my limited experience with Triumph clutches there appears to be several variables, a combination of which can lead to crunching gearchanges and slipping plates. With my 650, the biggest improvement was running the clutch with no oil and no outer primary chaincase, but not for very far, perhaps 20 miles in total.

IMO the main source of clutch trouble with the T type 3 spring clutch is a worn shock absorber unit. If this is gubbed, no amount of spring balancing , new plates , finicky adjustment, will make a blind bit of difference. The cush drive was never meant to be rebuildable, having tried I now categorise attempting to repair the shock absorber as a senseless waste of human effort, once worn it allows the clutch basket to tip under load, regardless of how fresh the plates and springs are or how clean the clutch tang grooves are.. The only non wearing part of the cush drive is the outer end plate; the spider , inner end plate, rubbers and notched drum are all wearing items. In the Uk a new clutch centre cush drive unit costs about 100£ , money well spent.

Now you all know why newer bikes have the Cush drive, if required, in the rear wheel drive…
Other than the usual few jabs to free the clutch, I have never had clutch issues on any bike..Well, I did have trouble with Barnett plates refusing to disengage on the race bike…
As Reverb says, some new bikes have difficulty finding neutral….I just find neutral as the bike comes to a stop..

I couldn't agree more. In fact I view it as service item to be changed along with the primary chain. I too gave up on rebuilding these a long time ago. The spider takes up all the force from the clutch springs which means that the T140 SA wears even faster than in a T120. The spider itself was given a bigger footprint at some point in time but it didn't help a lot. It's a poor design to be honest.
The earlier version with the ledge for the innermost plain plate doesn't have this problem but offers one surface less to carry the torque. Besides, when slop develops in the bearing, the clutch basket is left to wobble about even with the clutch engaged, so this is not a brilliant design either.
These clutches do seem to work pretty well anyway, sometimes surprisingly so, but a fresh one is always better.

SR

So does the Norton Commando.

I don't know about the 4-speed, but the 5-speed doesn't shift that well unless the main shaft is turning. Much easier to find neutral as you're coasting to a stop.

These are exactly the four parts I recently replaced in my newly-acquired T140ES. (along with a new hub). The spider was ground down to a knife's edge on the inner plate. The inner plate was worn to polished surface. The new spider was a loose fit on the hub. The spider wore that too.

Steve

Hi, Yes the splines, on the repro are loose. It's the spider splines, not hub. Yes they will wear. This just sucks! Be sure to loctite the clutch nut is all I can say.

Of course you could loctite the splines. That would work. Heaven help you if you needed to take it apart again. I guess you could heat it to 300f with heat gun. Rubbers would be junk anyway. I might do that next time.

I was going to machine spider square again, resurface back plate. Turn the shoulder deeper on outside to compensate. That would work. But.... The back plate is hardened. My lathe wouldn't touch it. Must be surface ground. I don't have surface grinder. I'd already filed grooves & they needed it again.

So I had to buy new one. Could not find genuine Triumph NOS. All the NOS parts were NOS Harris, NOT!!! Triumph. This is huge problem on eBay with NOS. Yes it's NOS, but actually is Harris or Wassell. Same crap as they still sell new, but with light layer of dust & rust. Luckily I'm 70 now so only need to get by another 5-10 years. Maybe less? Who knows? I don't even buy green bananas.
Don

Hooray,
Just took a short ride to gas up. I am now able to find neutral while rolling and with the motor running while stopped. One more reason not to totally trust the shop manual. Thanks for the help.

I was doing this subconsciously never realized why until now. Just always slight steady pressure until it slides into neutral easily when the speed is just right which is at about walking speed for mine. It will do it at a stop but it takes just the right amount of unforgiving pressure otherwise it is in 2nd.

The drum plates are a pain when they wear, and the splines, which allow the spider tangs to impact the drum inner, A method I'm trying is to lubricate the spider & ass with silicon grease, (organic grease will of course rot the older type rubber, which incidentally I've found gives a better cushion). First time I've tried this, and plan on disassembly inspection soon from a 'as new' clutch assembly. As to keeping organic oil out of the drum, I've sealed the plates on.