conquest clutch rebuild parts

[JohnF]

I'm going through my new '98 conquest and cleaning everything up. I thought I might pull out the clutches and rebuild them in the manner suggested by Rock Doctor here.

I've looked at the service and parts manuals and see that there aren't too many parts that appear need replacing in a rebuild. Does anyone know if there are kits?

What would you replace? Springs, nylon buttons, bushings, keys, weights-blocks,... ?

RD - you mentioned that you were waiting for parts to do a rebuild, what did you replace?

Part #s 127-71 (driver clutch) 126-24 (driven clutch)

And it looks like the only spot to get lube is the cam area of the driven clutch, right?

[Roger S]

Whatever the weights sit in (blocks, pucks, shoes) is what I tear up. They crack, and the lead weights spread them and the weights get worn and deformed. If it all looks good I guess there's no need to replace them. The shoes are shaped slightly different, one end goes up. I bought a new drive clutch because the bushings were worn a little.. I could see a little wobble in the shiv that moves as it ran. Couldn't figure out a way to machine and make new bushings economically.. they're not made to service, and the shaft had a thou or two wear. The shoes are $5 a piece, think the weights are $10+. If they are cracked at all, replace them. Get some fine graphite powder, and before you screw the cap on RD's mods, dump a couple table spoons of graphite in there in the spring chamber, for bushing lube. I'm proud of that trick I rub graphite all over the shoes and weights, everything that moves or slides. I think the stock spring might get weak with age, lowering the working engine rpm. RD's shim improves this and also improves downshifting.

The trans cvt unit.. all I do is index the spring in the 7? different holes. Mine came stock in #2. Moved it to 4 or 5 and it geared up much quicker. But it's back in #2 now. Depends on your rig, hp, torque curve, tires, altitude.. something you can play with. The shim stack in between the shivs can be lessened, moved to the inside. That will make the belt ride higher, = lower geared at beginning. I havn't done that, and it will also tighten the belt maybe making the tranny grind into gear.

[JohnF]

Looked over the parts page again and here is what I imagine to be the most a person would buy for a rebuild assuming the other parts are not broken and that the whole clutch isn't so worn that the whole should be replaced.

Driver clutch:

V10-48-105-17 spring, main (1)
C24-L1 *spring, anti-noise (3)
C13-266 weight, 266g (3)
0130-3002 block, red (3)

*The anti-noise springs fit behind the weights according to the picture. I don't recall seeing anything about them in the service manual or here.

Driven clutch:

ACS-3-188 spring, blue (1)
AMB-2 bushing, bronze (1)
ANS-2-T shoe, cam (3)

These things are so simple I will take them apart just to inspect them. I'll pay close attention to the blocks/weights (thanks Roger) and the cam shoes (as per the service manual). Springs do loose strength with use but I have no idea what this would mean with these springs. (about 250 hours use and 11 years in the clutch)

Get some fine graphite powder...

Hey, another good place for graphite is inside the twist grip. My throttle was sticking WOT pretty bad so I opened it up, cleaned it up, and dumped some graphite inside the grip - on the floor - on the seat - on my clothes - all over my hands - and a little on my face for good measure. It works great now.

[Rock Doctor]

I think you have it covered there, but I don't have my parts book with me to check (I'm at work).
Should'nt have to change the weights in the primary, unless damaged.
I find that lubricating the Clutch's is very important in allowing the clutch's to "Backshift". For me, when I start to notice a lack of performance, often it's just a need for lube on the clutches (Graphite Spray).

[Roger S]

They may have done away with those anti rattle springs, the last weight I bought didn't have a hole to accomodate it.

[JohnF]

The weights are drilled. I weighed them: 224, 226, 227 grams. These weights do have the little springs but boy are they in bad shape. Looks like they kinda get crammed up into the weight.

The blocks show wear but are not cracked or broken. The tops of two of the weights looked peened so they are touching on the outside.

Driven spring in hole 3.

Had an interesting moment a couple weeks ago backing off of the trailer. I was trying to creep down and about halfway the clutches let go. Wonder now if the light weights might be part of that.

[Roger S]

Lighter weights will let the engine's clutch let go of the belt at a higher rpm if you're doing compression braking, I found that out. You'll probably just have to experiment and see how it drives. I didn't shim my spring, I lightened the weights. I think the results are similar. You being at altitude could use a higher operating rpm.

[Roger S]

You may know this already, but argo sold two different weight sets, one heavier than the other.

[JohnF]

Lighter weights will let the engine's clutch let go of the belt at a higher rpm if you're doing compression braking, I found that out.

Yeah, me too.

You'll probably just have to experiment and see how it drives. I didn't shim my spring, I lightened the weights.

What is the mass you settled on?

You may know this already, but argo sold two different weight sets, one heavier than the other.

I've seen reference to 266g and 260g. Are these the two you are talking about?

[JohnF]

I think the results are similar.

You've got my inner nerd thinking with this statement. My gut is telling me this isn't true and here's why:

Centrifugal force is proportional to RPM squared.
Shimming the spring changes the force of the spring linearly.

So I imagine that changes to weights causes effects that are more RPM sensitive, that is, the force curve changes shape on the RPM scale, and spring changes translate the force curve up or down the RPM scale, same shape just in a bit of a different place.

Over all, I would expect spring changes to have a finer granularity when all you want to adjust is the operation RPM range.

But like you said, a person has to drive it.

[Roger S]

Can't recall.. read it in the manual a long time ago.

Just looked at my old ones and they are 225's.

I think I took a 1/3 of an ounce off each one. But shimming the spring should be a simpler result.

My armchair estimate is, shim the spring and leave the driven in #3. Then if you want to experiment, use the shim to set your rpm where you want, and the index holes to adjust how fast in upshifts at any given load.

[JohnF]

Hmm, again.

I've still been thinking about this. As I mentioned before centrifugal force is proportional to RPM squared - but you aren't changing the RPM. My mistake.

You are changing the weights - which would be linear.

So, both changes are linear and depending on the math a weight change may have finer granularity.

So all that other stuff I said was just an exercise.


225 you say. Interesting as that seems the weight whoever did the drilling was heading for.

[Roger S]

Let me clear up a few things not yet mentioned. RD has a conquest and I have a response with a modified briggs engine that likes to rev. The stock clutching was limiting my working rpm, so I lightened the weights, which moved the rpm up a 1000 or so at which it engages the belt and at which it operates as it gears up. It also gears down easier. All the weights I have ever used were 225's. I then lightened the 225's by about a 1/3 of an ounce each.

RD and I took different paths and reported similar improvements. Because you have a conquest and a stock engine, I suggest you do what he did.. plus shimming is easier than weights. You can always lighten the weights later but I would start with what he did. There was a dealer in Wyoming who set clutches up to let the engine run at 3600 all the time, for high altitude and tracks.

There's a conquest in the group I ride with, it always sounds like the rpm's are too low, lugging. My guess is heat and age weakens the spring. Just a guess.

[JohnF]

RD and I took different paths and reported similar improvements.

Roger, thanks for taking the time and making the discussion. I understand you and RD took different paths; it's understanding the theory behind those paths that will help me make a decision. Besides, I'm the guy that always wants to know how things work and these clutches are new to me.

You changed your cetrifugal force by about 5% (225g - 1/3oz)
Mine has been changed 15% (100-(225g / 266g))

I suspect for the very reason you mention the WY dealer made the change.

You are right, shimming is easier to undo if it doesn't work out.

I will buy some new weights.

[JohnF]

Ok, just so you all know how geeky I am...

I played with excel and I was right the first time.

Changing the spring rate translates the clutch force curve. The slope remains the same.

Changing the weight changes the slope of the clutch force curve. Proportional to the square of RPM.

F = (0.000341Wrn^2)-S

F - clutch force in pounds
W - mass of weights in pounds
r - radius of mass of clutch weights
n^2 - rpm squared
S - spring "weight" in pounds

I ignored that r changes a bit as the clutch operates and that S should really be a rate proportional to the "stretch" of the spring.

Less weight decreases the slope of the curve so if the clutch needs a certain force to come on line it will happen at a higher RPM. It also decreases the rate that the gears will change per RPM change.