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Bri

2014 txt pro 300 stiff clutch,250 pro softer springs ??

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Hello,I'm new to the forum and trials,I've just purchased a 2014 txt pro 300 it has a stiff clutch compared to

a txt raga 250 that I was able to try out this past winter.The 250 clutch was very effortless. I would like to make my 300

feel as good.I've researched some possible fixes ,measure clutch pack to make sure within spec,this is the first

thing I will do.  Does anyone know if the 250 comes with softer springs in the clutch  ,if so is there any issue with

installing a 250 kit in the 300.  I'm a beginner in trials ,I have been riding for several yrs on dual sport bikes and figure

it's time to learn some real skills.  thanks for any input.  

 

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So gasgas only has one spring, its called a bellevue spring basically looks like a ring. there isnt 5 or 6 or however many springs like moto bikes. This spring is only one they offer so cant really change it. Your clutch pack thickness is probably to thick which is why it is hard to pull. 

The clutch on 250, 280 and 300 is the exact same components and specs. 

Check thickness most people i know like 9.85-9.9mm thickness. you can go up to 10ish but that is hard pull(thicker the stiffer the pull). the minimum is 9.75mm so stay above that a bit for wear. Adjust thickness using different steel thicknesses. 

Also make sure clutch is bleed good and make sure it is all working correctly.

good luck 

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The fibre plates swell slightly increasing the pack height over a period of time, the steel plates don't change. All I've done in the past is remove and clean the oil from the fibre discs with acetone or celelouse thinners. Then gently rub both sides on a sheet of 320 or 400grit wet/dry paper placed on a good flat surface. As your rubbing the plate try to keep rotating it to rub evenly. Blow off the dust that's left and remeasure the pack height. It doesn't take much to get it down to 9.75mm so you don't need to put much pressure when your rubbing down. You can also give the steel plates a good run over with coarse sandpaper to take the glaze off. It will help to stop any clutch drag for a while until they glaze back up again.

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There is actually two thicknesses of Belville springs, but you would have the thinner one (1.5mm) in a 2014 bike. Part number MT280632015

There was a 1.7mm spring that is part number MT280232015 that was used from 2002 to 2005
Still used by some riders who favour the greater clamping force.

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It is the finger height that matters. 17.5 to 18mm is the sweet spot. You can cheat and just burn the plates real hard in 4th gear or take the clutch apart to sand the friction plates.

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Thanks to everyone for all the info,very helpful.

I'm not to clear on how to measure the finger height. It looks like there was video on that

at one point but no longer.  Is it the plate thickness that adjusts the finger height or something else?

Regarding the belville spring ,so I'm assuming that mine being the thinner of the two at 1.5mm it

would be the easier to pull one vs the 1.7 stiffer correct?

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Hi Bri, you can measure the finger height with the depth gauge on a vernier caliper, top of the fingers at the centre, down to the base of the clutch centre. Yes, it is the plate thickness that determines the finger height. Yes, the thinner belleville washer/spring would be easier to pull in. The clutch fibres swell when water enters the gearbox, either by drowning the bike in a stream or when the water pump shaft/seal wear and allows coolant into the gearbox, best to sort out those problems promptly when they happen. Bye, Peter B.

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gear oil will also over time swell the clutch plates...I've found that ATF oil has a greater effect on the clutch plates swelling but ATF is considerably cheaper than Putoline and the like so given that, I chose to use ATF and sand the clutch plates down once a year or so...

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Thanks  peter valuable information  , I have heard of many riders using ATF ,for now I've got a few ltrs

of 80w belray gearsaver. After getting more time under my belt riding I may try some different oil options.I will

keep the ATF in mind ,Thanks again to all, this is very helpful in getting me on the right track,or maybe the way I'll

be riding off the track completely ......

 

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Howdy Bri. Since you're in Alberta ... head to your local Canadian Tire and buy a pail of the Shell Rotella T5 10W30 Semi-synthetic diesel oil. It even goes on sale at times. The performance seems good as well as its low cost is conducive to frequent changes. Enjoy.

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2 hours ago, d2w said:

Howdy Bri. Since you're in Alberta ... head to your local Canadian Tire and buy a pail of the Shell Rotella T5 10W30 Semi-synthetic diesel oil. It even goes on sale at times. The performance seems good as well as its low cost is conducive to frequent changes. Enjoy.

Hi d2w.I've used the rotella in dual sport bikes I've had and It seemed to work fine but I've been told by a few trials dealers

now that I should not use synthetic oil in the trials bike,I geuss due to the heavy clutch usage. I take it you've been using it

with no issues ?

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To be honest I've only begun to use the T5 semi-synthetic recently, but so far I've had no issues which I can attribute to the oil. I've run Rotella 15W40 dino oil forever in my enduro and trials bike without issue. But on the suggestion of a friend I wanted to try a lighter weight oil in the trials (and hence the move to 10W30 T5). I'm only a recreational rider, and so may not notice any change (for better or worse). But I've always prescribed to the idea that frequent oil changes of mid-quality grades are more beneficial than long runs with premium grades.  I believe it's the carbon and metallic contaminants which harm an engine more than having insufficient lubrication. But, your mileage may vary.

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We use ATF because it hooks up better. And is also less grabby. Seems like everytime I sell a bike the NEW guy has to change to his brand of oil. And everytime they want you to ride it to see how well it works. I usually tell them how nice it feels, but you are not going to zap any ledge with that slow damn clutch. 

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As above. If you ride an easy line, go ahead and make the clutch as soft and progressive as you care to. If you're moving on to advanced techniques though, you want a clutch that hits harder, and you have to pay a bit of a price in lever effort to get that. An adjustable preload ring is the easiest way to go back and forth without messing with the clutch pack itself. Provided it's within spec, all you need to do is select one of the 3 settings, and the clutch will go from hitting like a hammer (with heavier lever pull) to being nice and, well, slow (with easier pull). They come on all the new GG's, but you can buy a Xiu ring.

Edited by heffergm
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