Yamaha TRX850 Enthusiasts Forum

Is it possible to fit a dry clutch to the TRX?

Yes - virtually anything is possible

But..... this would be very difficult and not cheap.

Why would you want to?

Probably to emulate that horrible ducati clutch rattle......Ps not that nice to ride with either

Don't want to hijack the thread, but I've often thought about whether a slipper clutch is possible?

When I change down fast and brake hard on track days, the back tyre squeals like a, err, squeally thing!

Again this falls in the possible but expensive category

phuk72 wrote:Again this falls in the possible but expensive category

I reckon I know how to do it.... (It'll still be expensive though)

Honk wrote

I reckon I know how to do it.... (It'll still be expensive though)

Well, do tell Lad.

Why? Do you have some other mechanical noise you want to hide?

trixynut wrote:Don't want to hijack the thread, but I've often thought about whether a slipper clutch is possible?

When I change down fast and brake hard on track days, the back tyre squeals like a, err, squeally thing!

You might want to try raising your idle adjuster when you are at the track. That and a little (more) finesse on clutch release.

I did A LOT of track time on mine over the past couple of years (including a 4hr endurance race), never once did I think it needed a slipper clutch.

Max wrote:Why? Do you have some other mechanical noise you want to hide?

Yes. I think the valves need adjusting.

The reason for thinking about the dry clutch was an image I had in my mind of oil swirling around in the clutch housing and sapping power from the engine. I guess I don't totally understand (or like?) the concept of a wet clutch...

A slipper clutch sounds like an even better idea. Do 4 cylinder bikes have as much compression braking as the TRX? Seems to like to squeak the rear tire on downshifts. I understand that I'm not a good street rider.

How high do you run your idle at the track?

I only turn mine up a bit, 1,500rpm or so. Some people go up to 3K.

throttle wrote:
Do 4 cylinder bikes have as much compression braking as the TRX?

Not normally, it tends to be a twin thing, presumably due to piston or combustion chamber size. Maybe something to do with compression ratios but I'm not convinced that twins have generally a much higher compression ratio. I guess it's easier to alter the speed of a four cylinder engine by force than that of a twin.

Personally I quite like the sliding rear tyre feel. Mind you my bike has what could be described as a manual slipper clutch. I'm still learning how to properly use it though. My Tuono has a slipper clutch (I think), but it makes little difference when the rear wheel is off the ground anyway.

honkdawillydahonk wrote:

phuk72 wrote:Again this falls in the possible but expensive category

I reckon I know how to do it.... (It'll still be expensive though)

I DO know how to do it, And you can get out of it surprisingly cheaply. Only problem is you need to get a brand new slipper clutch basket. Other than that, the mods are very minimal. (remember, a brand new clutch basket IS expensive.. you are looking at over 700USD in some cases. Depending where / what you want to get. Clutch plates are extra. dont forget new springs and so on and so forth.

If you know which basket to get and what parts to machine correctly. Im currently half way thru a vast engine overhaul on my spare motor.

Ive gone as far as custom 900cc conversion (done for almost next to nothing in value.. But i have access to machines which help), custom cut gears, and a few other special tweaks ive come up with.

ive NOT done this conversion, but ive physically held parts that im planning to use. I just dont like the outlay on such a project.. Money is expensive.

Compression lock is due to a few things. 2 of the largest factors (that im led to believe, i DONT know for sure, im no engineer) would be
1: compression ratio
2: torque of engine

Bigger compression obviously is harder for the piston to move up and down, thus wheel trying to do this would be hard, thus, wheel skip / compression lock.
More torque in the engine would want to "resist" a change in state.. So if you are off the throttle and in X gear, and the wheel is trying to do something that engine doesnt want to do, it can resist longer.

Try engine braking in different gears at different rpm.. Meaning this.

Ride 1st gear, 4000rpm, back off throttle and see reaction. attempt this in all gears. i suspect 1st would be more "savage" than any other gear.. mainly coz of the ratio of wheel and gearbox in this gear. 5th would have the least effect.. So down shifting around a corner would be bad times for compression lock

Repeat the process at 5000rpm and so on.. You can see how it effects your bike and your engine. The wheel will make the engine run at a certain RPM, If its starved of oxygen it may not be physically able to work that hard, thus, compression lock.

Please correct me if anyone does know, this is all speculation and my thinking from a brief over view on the mechanical process and stresses applied to engines.

Replying to the actual "dry clutch" question.. You need special air flow thru for cooling, different plates, block up a few oil galleries, hardened baskets and springs. It would inherently ride like a pig at low speeds. much like a ducati.

The actual advantages dont really exist on bikes and engines such as these. Dry clutches are MUCH noiser and need more "regular" servicing. They also prefer to be "snapped" on from what im told.. Its why dukes have a 2ndary "throw-out" for low speeds, which makes it sound like someone put 2 ball bearings in their engine and it tends to shunt along while idle and clutching.

Quan-Time wrote:

honkdawillydahonk wrote:

phuk72 wrote:Again this falls in the possible but expensive category

I reckon I know how to do it.... (It'll still be expensive though)

I DO know how to do it...

I DO know how to do it to actually..... (I've got a slipper clutch basket sat on my desk as I write this) I'm just not letting on until I've finished doing it....

oohh. You got one ? i cant afford one hope it goes smoothly.

Please tell me when you finish. Im interested to see how it works on a trx and what your thoughts are on "was it worth it".

goodluck and keep us posted !

Not sure that either the dry or slipper clutches are necessary or even better for the road.
My 650cc single cylinder road racer is converted to a slipper (but still wet) clutch and is better on the track, but I can't think when I would be shifting down while braking so harshly on the road.
I did notice the TRiXie getting a bit loose into turns at a ride day, but not uncomfortably so.
But 'better' isn't why you should do things like this anyway I suppose, just that you 'want' to.
So go ahead and have a go, it's only metal after all!