Triumph Rat Motorcycle Forums banner

1 - 20 of 20 Posts

·
Registered
Joined
·
12 Posts
Discussion Starter #1
The clutch on my 1975 T140V is very stiff to say the least. I have put a new clutch cable and adjusted springs etc but no real change. Is there an actual alternative full clutch that anyone could recommend that would make it easier to use?
 

·
Premium Member
Joined
·
9,688 Posts
Ensuring that the lever fulcrum is correct helps. Then adjust everything by the book.

Keep tight bends out of the cable. I use a venhill featherlight.

I use a 7 plate conversion with 650 springs. I also use an alloy pressure plate but I am not so sure that it actually does something.
 

·
Registered
Joined
·
3,161 Posts
Hi nhojk1, I don't know of a direct clutch that makes lever pull easier. However I have quite a bit of experience with this. I'll give you my thoughts. I think a 1975 would have same levers as my '73.??

I would agree the T140 clutch lever can be very hard to pull. They were very hard from new. A root cause was the 750 clutch springs were very much stiffer than 650 springs.

I would most strongly recommend lubing your new cable. Either with engine oil hanging cable like shop manual shows or a dedicated clutch cable lube that is injected into cable with a tool & aerosol can of cable lube. Lube perch pivot & upper cable end pivot in lever. That is always the starting point.

Are you using original perch or a replacement of some type? The distance from lever pivot to cable end center point is very important. I believe it should be 7/8".

Some owners use dogleg levers which can change the pivot didtance, but that's another subject.

I installed 650 springs as test with original clutch plates. I got acceptable lever effort, but the clutch would slip at times. I put 750 springs back in.

I installed Norman Hyde 7 plate +1 clutch kit & put the 750 springs back it. Normally I adjust the spring nuts flush with dome of nuts. It was said you back off nut until the studs were flush with slots. Over time I found backing nuts off like this tended to allow micro slip which reduced friction pad life, leading to premature slip. However it gave a very nice lever pull. Now I accept a little harder pull & put studs flush with domes. This has proven to be the best compromise.

Changing to an alloy pressure plate won't change lever pull one way or the other. Unless you want an alloy one for some other reason there is no reason not to reuse the steel plate.

Many alloy pressure plates have a smaller outside diameter which actually press the clutch stack in a less desirable fashion as the inside diameter of the friction pads is much greater than on stock clutch. So some of the alloy plates miss pressing on the friction pads to a greater extent than the original Triumph steel one. But the alloy ones still work ok. I've never had a problem with the steel ones so I just reuse them unless they have some sort of damage or are bent. Put on flat surface to check for bending as you would a clutch plate.

The 7 plate kits are simple install. You reuse rod, adjusting screw, pressure plate & all adjustments are like the original 6 plate.

Some sellers seem to think 650 & 750 springs are interchangeable. They are not! 57-1830 650 springs have 9.5 coils & are 1-3/16" long in real life.

57-4644 750 springs have 7.5 coils & are 1-3/4" long in real life. The wire in 750 springs is fatter also. .112" compared to .098" for 650 springs.

Ask seller to measure springs to be sure you don't get sent 750 springs. You want 57-1830. They can count the coils too.

I've found with all the T140 clutches I've been involved with. The correct lever pivot length, properly lubed new cable, 7 plate clutch with 650 springs has given the owners a clutch they can live with & ride all day. An added bonus is the clutch cable has less strain on it, so it doesn't break as easily. You could always back off the springs slightly as I did at first & live with shorter clutch life. It was still about 10k+ miles.

All this is assuming the ball cam is in good shape & adjuster screw is not hitting the inspection cover in primary cover or something odd.

Peg has installed a hydraulic clutch system to replace the cable. Maybe she will jump in & elaborate on that. I've never felt that conversion so I don't know how much it helps.

I hear good reports about Areco 7 plate kits also, but I have no personal experience with them.

The friction pads on 7 plate are very thin, so you can get the extra plates in the same space as the 6 plate takes.

Don
 

·
Premium Member
Joined
·
9,688 Posts
One thing that it could be is that the actuation mechanism in the gearbox cover might have been replaced at some time with a 79 on one.
They have the same part number but the later one has an X added. It's designed for the 79 on levers
 

·
Registered
Joined
·
3,161 Posts
Hi Dave, How much difference do you find it makes? Codeman installed one on '76 T140. Didn't seem to notice a real difference. Clutch released fine with the X cam. The old cam was very worn at the pivot causing a lot of lost motion & low lift.

Seems like the X cam is often sold under prior part #.
Don
 

·
Registered
Joined
·
7,365 Posts
650 springs will make for a lighter pull on the lever. They are smaller diameter metal. Try a set. It might slip a little in 3rd gear if you give it a large throttle but not in the other gears. Routing cable loose and without any sharp turns helps as does a venhill featherlight cable and an alloy cover much the same as Daves set up. I still use 6 plates.
 

·
Registered
Joined
·
3,161 Posts
Hi All, I've seat of the pants observed the way a T140/TR7V makes power is a little different. Pretty much all that changed 750 springs to 650 springs have experienced clutch slip overall under certain power bands.

This has always puzzled me. The T120T 750 so far as I know uses 650 springs with at least decent results. I know a few guys with Morgo 750 kits & 650 springs. Clutch works fine. The Morgo kits make more power the way I feel it riding bike than 650. Yet the clutch with 650 springs doesn't seem to slip.

650 & 750 clutches take the same clutch plates & pressure plate. Why does the T140 tend to slip with 650 springs? Does the short rods change the torque curve such it puts more torque through clutch for an instant?? I ride T120, TR6 now & then. When we swap bikes both riders are bewildered at how they can feel so differently the way motor runs.

Any thoughts or experiences?
Don
 

·
Registered
Joined
·
508 Posts
Hi All, I've seat of the pants observed the way a T140/TR7V makes power is a little different. Pretty much all that changed 750 springs to 650 springs have experienced clutch slip overall under certain power bands.

This has always puzzled me. The T120T 750 so far as I know uses 650 springs with at least decent results. I know a few guys with Morgo 750 kits & 650 springs. Clutch works fine. The Morgo kits make more power the way I feel it riding bike than 650. Yet the clutch with 650 springs doesn't seem to slip.

650 & 750 clutches take the same clutch plates & pressure plate. Why does the T140 tend to slip with 650 springs? Does the short rods change the torque curve such it puts more torque through clutch for an instant?? I ride T120, TR6 now & then. When we swap bikes both riders are bewildered at how they can feel so differently the way motor runs.

Any thoughts or experiences?
Don
That is a good question, because my 68 650 seems to have as or more power than my 79 750. I have played around with springs on both of those bikes, and found the 500 springs work fine on the 650, and the 650 springs work fine on the 750. But the 750 springs are an extremely hard pull.
 

·
Premium Member
Joined
·
9,688 Posts
Hi Dave, How much difference do you find it makes? Codeman installed one on '76 T140. Didn't seem to notice a real difference. Clutch released fine with the X cam. The old cam was very worn at the pivot causing a lot of lost motion & low lift.

Seems like the X cam is often sold under prior part #.
Don
I honestly don't know but it equates to having the "wrong lever perch" even if the lever is original.
The lever and actuator work as one and mixing them up throws out the lift.
 

·
Registered
Joined
·
158 Posts
Hi All, I've seat of the pants observed the way a T140/TR7V makes power is a little different. Pretty much all that changed 750 springs to 650 springs have experienced clutch slip overall under certain power bands.

This has always puzzled me. The T120T 750 so far as I know uses 650 springs with at least decent results. I know a few guys with Morgo 750 kits & 650 springs. Clutch works fine. The Morgo kits make more power the way I feel it riding bike than 650. Yet the clutch with 650 springs doesn't seem to slip.

650 & 750 clutches take the same clutch plates & pressure plate. Why does the T140 tend to slip with 650 springs? Does the short rods change the torque curve such it puts more torque through clutch for an instant?? I ride T120, TR6 now & then. When we swap bikes both riders are bewildered at how they can feel so differently the way motor runs.

Any thoughts or experiences?
Don
Hi TR7RVMan, I have been thought long and hard on these, while fruitlessly experimenting for a long time, I've suffered the mind boggling hand freeze fatigue during long runs for years, where only a forearm can suffice on the lever resistance that only gets worse as the heat increases, this is on a 1961 650 mind.

The final solution I have arrived at is:-

Lever, Hinckley Speed Twin, adjustable throw. (RH, turned upside down).

Cable, Teflon Lined, routed on 3 cable guides.

Clutch actuator, re-engineered to finer tolerances, (all pivots bushed with PTFE thin wall plain bearings.

Re-made actuator arm & adjuster pivot with positive location and ball adjuster.

Shorter push-rod to suit, arm @2mm shorter).

4 spring Alloy pressure plate and thrust bearing.

7 plate conversion, (std) plates.

4 spring duplex drum.

Basket thrust washer.

Std 650 springs.

SAE 20W oil.

As I remember, I had to shave the innermost bonded plate to fit all in and make several adjustments to suit inc reducing the 'new' adjuster on the pressure plate. The result has surprised me, 1/2" past 1/8" slop, hand lever movement fully disengages clutch, additional pull is superfluous, and can be achieved with one finger, and I don't have fingers like Mr Fury, the best is, it does not show any signs of drag or slip under any conditions I have subjected it to to date. The re-engineering of the mechanism started as a improvement for the slick shift, and that works better than ever, up and down the box, which is a revelation. The movement to actuate is about 2.5mm.

So, maybe I'm lucky, maybe things can be improved, what I do know is it's the best I've ever experienced and a pleasure to ride any distance. Only 300 miles on this set-up to date, hope it last's. :smile2:

Original post, https://www.triumphrat.net/classic-vintage-and-veteran/947514-clutch-query-to-modify-or-not.html
 

·
Registered
Joined
·
541 Posts
Thanks everyone for the excellent info and advice in this thread!! The clutch pull on my new (to me) 1980 Bonnie is diabolical, though I'm waiting to put a few miles on here to see if it eases a bit, as the motor is quite fresh and tight, and has some rather thick-looking oil in it. Once I get onto some plain Castrol 20/50 it just might settle down too. However, I'll be modding things along some of your lines if not, so better bookmark this thread
cheers from near-Antarctica - Pat
 

·
Premium Member
Joined
·
9,688 Posts
Take the tank off and let the clutch cable become loose and in big curves
See if the pull improves
Often it's just the routing that cause issues
 

·
Registered
Joined
·
3,161 Posts
Hi Freakmaster, Wow! That's really good stuff you did! Do you have any photos of what you did? I've most curious about the ball cam modifications.
Thanks, Don
 

·
Registered
Joined
·
541 Posts
yes, good idea!! My old mate who turned me onto Triumphs in 1979 told me that - he has enormous loops in his cables, and never seems to have problems. Might try that as a possible non-invasive solution, thanks mate - cheers Pat
 

·
Registered
Joined
·
12 Posts
Discussion Starter #16
Hi Don, thanks for great advice, I have a new Venhill featherlight cable and have re routed it as good as can be. Where is the best place to purchase the Norman Hyde 7+1 clutch
 

·
Registered
Joined
·
158 Posts
Hi Freakmaster, Wow! That's really good stuff you did! Do you have any photos of what you did? I've most curious about the ball cam modifications.
Thanks, Don
Hi, not good at posting pictures, always told file is oversize. but i'll try and say how it went, The cable actuator arm, linkage and bearings were remade in entirety with a little over 2 deg extra positive throw achieved on the slide over adjuster arm.
These arms are always sloppy with poor retention, so took care to give a tight positive lock on that with HT grub screw to bear on a milled flat of the shaft. The reason for this was to improve max leverage, which if you look at one, they go just over the effective lever fulcrum at the point of clutch release, meaning the actuator leverage suddenly dies at the point of max movement, this does not capitalize on the leverage available.

I could not decide initially was this inefficiency due to wear, sloppy new tolerances, or design, or maybe the cumulative effect of all just proving excessive, so decided to try and accommodate all possibilities and engineered it all with tight tolerances and a conservative 2 deg additional positive angle.

I then found the reason Triumph accepted this was because the screwed adjuster would otherwise impact the mainshaft end at the point of it's most effective leverage and perhaps reasoned even changing the actuator design the engineering changes could not justify the result? So, the original ball ended adjuster was remade so the rod to ball contact was possible without the ball's retention wall contacting the mainshaft. In hind sight, I could have made the arm a couple of mm longer to compensate for the extra travel, and it did occur to me I may be wasting my time as such a small adjustment of 2 deg may make no difference, but remaking the arm assembly again is a daunting prospect.

The new actuator arm was also fitted with a small deep grove roller bearing on a shouldered screw to ride the slickshift cam, which was reground to a flat profile to suit, as the original takes a rounded roller. The slickshift it'self would not work with the 5 speed cluster, as the 5 speed quadrant selection throw was to little. This was overcome by using a 4 speed quadrant, with 5 speed selector plungers.

The throw was adjusted (limited) by welding ears' (flats, building up with weld) until the max throw equaled enough to work the slickshift cam without over selection, about 2.5 mm either side, but it's throw potential is different each side of the quadrant by virtue of the casting differences so needed to be experimented with. There was fine tuning necessary once fitted, the mechanism is stronger and more robust than original and should last better than original. Over all I could not be more pleased with the result, in fact I'm astounded. But I do feel that over-all the solution is the sum of what's been done, rather than any single modification. It's really hard to say as you only get the final result by the experience of the ride, as no one mod was tested in isolation.
 

·
Banned
Joined
·
47 Posts
FM - I am also impressed with what you have achieved.
My slickshift type box has all of the sloppy aspects that you have dealt with (though I have never had the slickshift knob). I always thought it a crude idea, appealing only to boy racer braggarts,but it seems that you've re-engineered it to be useful.
Have I understood correctly that you are employing this with a 5-speed box? That is truly impressive, and that you can use the 4-speed quadrant (modified as you describe) with the 5-speed camplate.
This is worth an article for our illumimification.
 

·
Registered
Joined
·
3,161 Posts
Hi nhojk1, I've always gotten mine direct from Norman Hyde website. They have the best price.

https://normanhyde.co.uk/meriden-triumph-bsa/triumph-t140-tr7/hyde-clutch-plate-set-7-plus-1.html

You want 57-1830 9.5 coil. Look at the photo & count coils. Remember 750 springs are 7.5 coils. Easy to count in decent photo.

Hyde sells these 650 springs, but no photo... So you're on your own.

https://normanhyde.co.uk/meriden-triumph-bsa/triumph-t120-tr6/clutch-spring-set-3-x-57-1830.html

These are the springs I like to use. I don't know if available in UK. No photo here either, but they replicate tension & size of original Triumph 650 springs.

https://jrcengineering.com/product/57-1830/

My feeling is most of the 9.5 coil springs would be close enough.

You don't need to get pressure plate, rod, anything else unless they are worn or damaged. Doesn't matter where you put the new steel plate you get in kit. It will be smooth. Don't roughen it. Trust me... Follow the instructions oil the new friction plates well. Soaking overnight in the same oil you have in motor is not a bad plan. In any case make sure friction pads are fully saturated with oil. Oil the tangs on all the plates well. Oil steel plates also. At first start up the clutch will usually drag for a few starts until the excess oil flies off. Then it will be good. Adjust the rod after 30+ miles, or the next day, then again in a few hundred miles. Always adjust rod on cold motor after sitting overnight. It doesn't change too much after the bedding in of plates. After that I check rod adjustment at every 1500 mile oil change.

If the rod adjustment is too tight & causing slipping, you can smoke the plates very quickly, like 1 day. The pads are very thin & overheat instantly if it slips.

I just took my plates out today to replace the cush hub rubbers. 7k miles on friction plates. Very minimal wear. I'm quite pleased with the wear. I will reinstall these plates & expect to get at least another 7k miles from them if not more. I smoked my first 7 plate by not having spring nuts tight enough & didn't adjust rod in time.

You will not be disappointed. I've never heard of one person regret the 7 plate conversion.

How many miles is on your Venhill cable. I never cleaned or lubed my Venhill in 3k miles the top end pulled off. The cable friction had built up due to the liner deteriorating. Had a pile of Teflon or whatever it is balled up at the lower end.

Stuart has very good results from Venhill. Ask him exactly how he maintains his cables.

I only use Barnett cables. Not lined. Lube with motor oil. They are as easy to pull as Venhill. They are very strong with swaged steel ends. In UK you'll have to buy from a US parts seller as it seems nobody in UK stocks them. I know your import duties/taxes will push price up dramatically, but I think Barnett is still worth you cost.
Don
 
1 - 20 of 20 Posts
Top