Triumph T140V Bonneville SRM Clutch Pressure plate upgrade
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- Опубликовано: 17 июл 2024
- Curing the poor clutch action and frequent drag on my 1978 Triumph T140V Bonneville by installing a SRM alloy pressure plate kit and new springs.
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Good job mate, you've clearly got better knees than I have !!
Well done mate 👍
Thanks 👍
Fitted a one on my T120 in the seventies when they were made by devimead used a four spring one along with a A65 four spring clutch centre worked well
if u remove gearbox outer cover u can measure correct length by measuring protrusion of pushrod in situ and fit another and cut to the same protrusion hth
Quenching the clutch pushrod,case hardened ends involved .My understanding was gas torching the pushrod ends till they were cherry red then dunking them in oil.
Yes, that’s what I did once the length was correct.
Great video young man.😊
Love it!
Thank you
Never mentioned that he slackened the clutch at the handlebars first before doing anything to the clutch if not it would explain all the F about with the length of the pushrod...
Cable was completely disconnected for initial install as original had snapped (which I believe I mention in the video) so needed replacing,and for each rod length adjustment it was completely slackened off. Push rod length is fairly critical with this kit as the adjuster screw assembly is longer and sits inside the pushrod tube rather than balancing in the end of the push rod as with the original design. This is what helps give a more even lift.
A good job mate, what was the length of the rod in the end, did you measure it? I have to do mine on my TR7RV 1978. I have the SRM but I think the rod was cut too much as I have excess clutch cable length and have to have all my adjusters on the cable screwed out to the ends. It would be helpful to me if you did measure yours. Thank you for sharing.
Will check my notes, I think it ended up 2 mm shorter than my original cut.
That's very kind of you, thank you.@@barnsleybikervideodiary7694
Originally I cut mine to a length of 296mm, after a trial fit I removed another 2.5mm . I tightened the springs down so the the threaded top of the threaded stud is just flush with the bottom of the slot in the ‘nuts’. A ride in traffic including a few road works and hold ups yesterday and it performed faultlessly, no drag, no slip.
Thanks, that will be helpful.@@markgallagher2386
Apologies- that should read 269 then another 2.5 mm - my dyslexic stubby fingers.
Hi; actually a billet pressure plate is not better than the original as is well known. I have 2 79´s; one with a billet and one with the original BUT and that is a BIG but; I have a N Hyde 7 plate clutch and in the other I have the MAP 6 plates; so if you have poor action is due to:
1-bad tuning of the pressure plate.
2-worn thrust washer
3-sticky plates
4-bad adjustment of the rod
5-wrong cable adjustment
6-indentations in the basket and drum
7-worn plunger in the gearbox
etc
With the plates I mentioned you will never ever suffer with drag; sticky or whatever in the plates. No matter if you do not use the bikes for months; never stick.
FIT the plates DRY. Oil is for the chain not for the plates.
All can say is after the upgrade every thing works much better, no drag, no slip and a much lighter lever action. My thought is that the original design relies on the adjuster balancing on the push rod which is a bit like balancing a penny on a pin head. On the up grade the adjuster screw is longer and contacts the push rod inside the push rod tunnel so less chance for pressure plate to lift unevenly and the addition of a bearing between the pressure plate and adjuster screw mechanism helps spread the load of the lift. Either way more than happy with the result.
Hiya, I’m trying to fit the SRM pressure plate but not finding it easy. My pushrod was barely sticking out of the main shaft to start with, what length did your pushrod end up. I think I might have mine over long still. John
Ended up with pushrod approx 266mm long. While working to get length correct I had to use a magnetic pick with a small dia. Head to extract it for adjustment.
@@barnsleybikervideodiary7694 Hi, thanks mate. I’m at about the same dimension. I found their instructions a little confusing. The starting position for My pushrod only protruded a couple of millimetres.
I’ll try reassembly now, I have other selector problems trying to resolve at the same time.
Your bike sounds lovely.
Regards John
Invest in a bike lift be the best 'upgrade' your knees could have...not good kneeling on the floor.
Where did you get the oil pressure gauge from?
Mike 750 owner
It was on the bike when I bought it. The bike was ‘built’ in California then found its way back to the U.K. I have been asked this question before but haven’t managed to find a makers name?
Hi folks. Morgo in UK do them. Were about £80 and easily fitted yourself. Had mine a few years now on 1981 750E and so much more reassuring than a bulb!
Those holes could be why to me, it sounds like it's slipping like fck. You've reduced the friction area considerably.
It never suffered with slip, but dragged when hot no matter what I did to adjust it. Now rides and operates much better and more consistently. Before I’d have to adjust it several times on a ride? The holes where already there, hence my question as to trying to identify them. Before the modification I had done approx 4000 miles without any slipping, and once adjusted correctly haven’t experienced any problems with either drag or slip.
I would agree that the clutch is slipping a lot. I bet at 4000rpm in top the engine will spin up to a very high rpm if you give it throttle. Probably about 5500 rpm without any increase in speed.
There is a long debate on a T140v FB page ref the drilled friction plates. Before fitting the upgrade kit my issue was clutch drag in heavy or stationary traffic. After the mod and correct adjustment I can assure you there is no slip, no drag and smooth consistent clutch action. In fairness I’m riding it, I know how it feels and performs and have nothing to gain by making claims that aren’t true. Replacing the original pressure plate with new genuine parts may have also cured my dragging issue but would have cost nearly the same. The flaw in the original design is it depends on the balance of spring pressure to keep the lift of the pressure plat even while balanced on the end of the push rod and adjuster screw. The upgrade allows the adjuster to fit inside the push rod ‘tube’ and uses a thrush bearing to help spread the load making even lift easier to achieve.
Regarding the drilling of the friction plates - reducing the surface area will increase the pressure on the contact surface and should increase friction but also probably wear rate. It’s the same theory as comparing a stiletto with a snow shoe on a soft surface.
@@barnsleybikervideodiary7694 Reducing surface area cannot increase pressure. In theory, reduced area due to holes in plates might microscopically force clutch material into holes turning it into a grater.
Its like the dills who excessively drill the fins on their engines to somehow improve cooling. They are actually reducing cooling area of heads and barrels. People do dumb stuff.
@@romandybala a stiletto heel exerts greater psi than a flat shoe. In the video I never claim the plates work better, just asked for help to identify them. The clutch issue wasn’t slipping but dragging when hot. The modification sorted the problem without having to change the plates and gave lighter, better operation.
31mm your sure not 3.1mm
@@pattoallen1981 definately 31mm, the operating mechanism on the SRM kit has different adjustment method and includes a thrust bearing which combine to take up the lost 31mm .
Having those holes in the plain plates will cause clutch slip. It has removed a lot of the friction the plain plates are there to provide. I also have an alloy pressure plate on my T120r with 750 kit and it has been good for a very long time so far. Cost me £30. Some videos of my bike at high speed on my channel
So why do drilled brake discs work more efficiently than solid ones? Actual friction or pressure will be higher for a given spring rate as contact area is reduced so psi (or whatever units you want to use) will increase.
Ps the drilled plates were fitted by a previous owner and weren’t giving a problem. As stated in the video and in my comments the problem was severe clutch drag.
@@barnsleybikervideodiary7694 They dont work better. Its just a thing racers did to look faster. No one ever drilled drum shoes to make them "better".because you couldnt show off drilled brake shoes to your mates.
Take it to extremes and imagine you drilled really big holes in the discs ,would they work better? I dont think so as you have taken away the braking surface area.
For normal everyday riding if a drum brake can lock a wheel it is the same as a disc. Discs are better only on really high performance machines as they dont fade as much as shoes as they are open to the wind. Plenty of single leading shoes can skid a tyre , what more does it need to do?