spenser Posted March 17, 2017 Report Share Posted March 17, 2017 There are two things that can affect the degree of effort needed to pull in the clutch lever: clutch pack total thickness (affects angle of the fingers and leverage ratio), and strength of the Belleville spring. GasGas used a heavier spring until about 2007 on their pro bikes, after which they feather light and very effective if the clutch pack was set to the recommended height (thickness). The adjustments needed to the clutch pack thickness affect clutch bite, ease of pull, and if really out, they may not completely disengage, or on the other end, may slip under load. I have ridden a few TRS bikes, and it would appear that the first run needed more effort, whereas later production runs were much lighter to pull with no apparent loss of function. For a factory to react this quickly to feedback from clients is, in my mind, commendable. I am sure that anyone with a TRS clutch that they feel requires too much effort to pull can make the necessary modifications to "fix" it. Spencer Quote Link to comment Share on other sites More sharing options...
worldtrialchamp Posted June 27, 2017 Report Share Posted June 27, 2017 "2spd rear end"....what does this mean? Quote Link to comment Share on other sites More sharing options...
heffergm Posted June 27, 2017 Author Report Share Posted June 27, 2017 Quote Link to comment Share on other sites More sharing options...
gleiwitz Posted August 24, 2018 Report Share Posted August 24, 2018 Unfortunately I have a problem with hard working clutch. I am a hobby rider and I compete in the hobby class. My TRS is from the first hundred that was produced. I absolutely love my TRS it is a great bike but my finger suffers a lot during competitions or longer training. I wanted to ask if anyone has already found a specific solution that will solve my problem? I would like to get an answer which part I have had to exchange to make it work easier and where to get it? Quote Link to comment Share on other sites More sharing options...
lineaway Posted August 25, 2018 Report Share Posted August 25, 2018 They make three different bellvue springs for the clutch. Hard, med. and soft. That is what I would start with first. I think they only had the hard to start with. 1 Quote Link to comment Share on other sites More sharing options...
gleiwitz Posted August 26, 2018 Report Share Posted August 26, 2018 On 25.08.2018 at 4:58 PM, lineaway said: They make three different bellvue springs for the clutch. Hard, med. and soft. That is what I would start with first. I think they only had the hard to start with. I checked in parts manual 2018 and there are actually three types of clutch spring support soft, hard and med. The only question is whether it will fit my 2016 clutch. Quote Link to comment Share on other sites More sharing options...
section swept Posted August 28, 2018 Report Share Posted August 28, 2018 On 22/02/2017 at 8:18 AM, 2stroke4stroke said: Who would have imagined, as we spent five minutes adjusting the spring tension on our Bultacos to get the plates to lift square back in the Seventies, that progress would be such that this far in to the 21st century people would have to be messing about with emery to get a clutch to work properly? Surely modern design and, more to the point, production methods, can do better than this. My 72 Sherpa with careful assembly and attention to the clutch pivot shaft has a clutch that can easily be worked with two fingers and the clutch has all of its springs (new) and does not slip, judder or cause grief of the type these modern clutches do. Here’s a mod throw the clutch away and fit an early Bultaco unit???? Quote Link to comment Share on other sites More sharing options...
baldilocks Posted August 29, 2018 Report Share Posted August 29, 2018 With careful assembly and careful attention to the pack height a diaphragm hydraulic clutch is significantly better than a Bultaco clutch and can be operated with one finger. The Bultaco was a great bike in its day, that day was nearly 40 years ago. 1 Quote Link to comment Share on other sites More sharing options...
section swept Posted August 29, 2018 Report Share Posted August 29, 2018 (edited) 4 hours ago, baldilocks said: With careful assembly and careful attention to the pack height a diaphragm hydraulic clutch is significantly better than a Bultaco clutch and can be operated with one finger. The Bultaco was a great bike in its day, that day was nearly 40 years ago. Yes and how right you are. Having spent a good deal of time working with ‘modern clutches’ of all types I have to say the dual mass flywheels that fall apart and diaphragms that crack, together with multi plate competition clutches that only work on or off no matter how careful you are the old ones are the best. In the effort to provide a slim clutch assembly, which is lighter and has little inertia the manufacturers have created a whole new raft of potential faults and transmission issues. Small,wonder then that modern day super bikes and smaller commuters with selectable gears still use clutches that are similar to the ‘older types’ all be it the operation is hydraulic and ramps allow varying stages of engagement. I suppose the telling question is how often was the Bultaco clutch stripped apart compared to the ‘new’ offerings, on modern day bikes.? Edited August 29, 2018 by section swept Quote Link to comment Share on other sites More sharing options...
baldilocks Posted August 30, 2018 Report Share Posted August 30, 2018 (edited) No trials bike has a dual mass flywheel. My understanding of the function of a dual mass flywheel is to dampen the effect of the firing sequence on powerful multi cylinder engines. Family cars can now be 120 - 200bhp so more than a cortina which didn't have a dual mass ? The comparison is interesting though in that whilst the dual mass does fail it's coping with a diffent level of power to an older engine. It would be reasonable to compare the effects on a modern engine of fitting a solid flywheel and seeing what happens, what problem were the engineers trying to solve ? Back to trials bikes I started riding in the Bultaco era, when you got told off for touching the clutch in a section at the trials school. Yes you can set one up to work ok but it's a fine line between dragging and slipping. Power output, section design etc have all changed but if you ride twinshock events then it doesn't really matter. When it works the diaphragm clutch is good. The nearest to the Bultaco clutch still being produced is in the 4rt and Beta. Go and have a read of their issues. In terms of adjustment you can adjust the pack height to get faster / slower action which also effects the clutch pull. For the gas gas you can get different thickness steel plates. Once you are happy that the clutch suits you as long as you stick to the same oil it will not need to be adjusted again. Oil is important as some oils react with the clutch fibres. Edited August 30, 2018 by baldilocks Quote Link to comment Share on other sites More sharing options...
section swept Posted August 30, 2018 Report Share Posted August 30, 2018 Totally agree with you baldilocks, and the Beta clutch fix seems to be still going on with more posts....removing the dried compacted glue and generally removing excess manufacturing product, doing what the factory should have done in the first place. I know there aren’t any dual mass flywheels used on bikes...yet...but they might develop a much smaller version? Quote Link to comment Share on other sites More sharing options...
b40rt Posted August 30, 2018 Report Share Posted August 30, 2018 5 hours ago, section swept said: I know there aren’t any dual mass flywheels used on bikes...yet...but they might develop a much smaller version? I hope not, mine just tried to eat its way through the gear box ! 1 Quote Link to comment Share on other sites More sharing options...
baldilocks Posted August 30, 2018 Report Share Posted August 30, 2018 (edited) On 24/08/2018 at 8:07 PM, gleiwitz said: Unfortunately I have a problem with hard working clutch. I am a hobby rider and I compete in the hobby class. My TRS is from the first hundred that was produced. I absolutely love my TRS it is a great bike but my finger suffers a lot during competitions or longer training. I wanted to ask if anyone has already found a specific solution that will solve my problem? I would like to get an answer which part I have had to exchange to make it work easier and where to get it? A new spring will be quite cheap and easy to fit. You just need to take the inspection cover off , just four bolts not the whole clutch cover, then remove all of the 7mm head small bolts. The beville spring is under the pressure plate. If that doesn't work then either reduce the thickness of one of plates or by 3 new fibre ones. With the correct spring and the clutch pack measuring 9.85mm it should be light enough for you. Edited August 30, 2018 by baldilocks 2 Quote Link to comment Share on other sites More sharing options...
section swept Posted August 31, 2018 Report Share Posted August 31, 2018 17 hours ago, b40rt said: I hope not, mine just tried to eat its way through the gear box ! Can you repair it or has it done a lot of damage? Quote Link to comment Share on other sites More sharing options...
b40rt Posted August 31, 2018 Report Share Posted August 31, 2018 4 hours ago, section swept said: Can you repair it or has it done a lot of damage? This is on a sharan, one of the springs in the dual mass FW made a bid for freedom through the circumference of the FW. Caught it just in time. Just the housing thats slightly scored. Flywheel / clutch had 122k miles which is pretty good value. Quote Link to comment Share on other sites More sharing options...
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