New clutch, sloppy launch

[pk1]

I've just upgraded the old cooked clutch in my 70cc big bored Minarelli-powered Adly to an Artek K2. The Artek has great cooling but I can't seem to get the snappy launch out of it that I was getting from the OE clutch and bell when it was newer, which I'd drilled along with the cover to keep the temperature out of it.

The only thing I haven't changed yet is the OE belt. It's pretty new and is still 17mm wide - well within tolerance. Would a Kevlar belt make any difference? Or is there something else I'm missing?

I've included a couple of photos so you can see the setup - sort of.

[ryan_ott]

I’m not familiar with that exact clutch but you may need to do some spring adjustments or change them out to get what your looking for out of the clutch.

[snaker]

Did you replace just the clutch or the whole driven pulley assembly?

[harleyracer59]

not sure on that clutch but most aftermarket clutches need to be "broke in" or evened out. I bet if you take off the bell, your pads are not grabbing 100% there will be spots that are high that need to be worn down or rode in or fitted so that the whole clutch pad will make contact.

[ThaiGyro]

That "fine" adjustment on your clutch...did it come with a "how to make it fine?" Lots of things could be in need of attention. NMI (need more info). Does the clutch have a specific shim for that engine? Do you have different springs?

What about the other end? Is the variator OEM? Like snaker said...

[gsx600racer]

I wouldn't suggest a kevlar belt. They are tougher than stock, but expect them to wear your variator and drive face(if aluminum) quicker.

[pk1]

Oct 8, 2018 5:28:23 GMT -5 ryan_ott said:

I’m not familiar with that exact clutch but you may need to do some spring adjustments or change them out to get what your looking for out of the clutch.

[pk1]

Oct 9, 2018 0:42:17 GMT -5 gsx600racer said:

I wouldn't suggest a kevlar belt. They are tougher than stock, but expect them to wear your variator and drive face(if aluminum) quicker.

I've had no experience with Kevlar, and someone has suggested aramid as a good alternative. Apparently malossi do aramid with a stickier compound, which, I assume, will wear quicker than the other mechanical parts. have you any knowledge of aramid?

It seems every time I fix one problem I mange to move it along the drive train and back again. Sigh.

[pk1]

Oct 9, 2018 0:28:48 GMT -5 ThaiGyro said:

That "fine" adjustment on your clutch...did it come with a "how to make it fine?" Lots of things could be in need of attention. NMI (need more info). Does the clutch have a specific shim for that engine? Do you have different springs?

What about the other end? Is the variator OEM? Like snaker said...

[pk1]

Oct 8, 2018 9:49:09 GMT -5 snaker said:

Did you replace just the clutch or the whole driven pulley assembly?

[pk1]

The kit comes with two spring weights. It's unusual in that the springs are installed through the shoes and are in a compressed state when not in use. I've found the best weights of the two which are working real well with the variator weights. It's when the clutch heats up that I start to get slippage when taking off. No problems with maintaining top end though.
The finer adjustments are done by swapping out springs (two options). The ones I have in there seem well-matched to the variator weights so I'm getting not bad takeoff now, but there seems to be more slippage as the heat comes on. The slippage can vary depending on the day, which is leading me away from the clutch towards the belt.
The springs in this system are accessed through the shoes and are screwed into a compressed state when at rest (this can be done with the bell in place. Each full turn of the adjusting tool is 0.8mm, so it's trial and error to find the correct tension for your riding style. More tension holds well on the hills and I seem to have that nailed.
The variator is OE with 6g weights. I swapped it out for an aftermarket racing one but for the OE gave me better all round performance and better acceleration. I'm considering sliders rather than rollers the next time I do some maintenance on it. Any thoughts on sliders as well?
I only replaced the shoe plate and bell. The contra spring is a 1k and has travelled about 4,000 miles.

[snaker]

I did some researching on that clutch and from the few pictures I could find I can't make heads or tails of how that thing works.
Any chance you could do some disassembly of the clutch with photo's?

[snaker]

I found this photo if its the right one. I think the area on the left that I circled yellow is showing a white spring?

The red line would be the spring passage?

Is the large screw head at the pivot point of the shoe and if so is the screw at the bottom the pivot for the shoe going up the left side?

[pk1]

Hi Snaker, that's it exactly. It's a pretty funky setup. I'll take some next time I pull it down. The cool thing is you can change and adjust the springs without taking the clutch out or removing the bell, which has holes through it that match those in the shoes. It runs very cool compared to the OE one, probably because it engages so positively. I think that's where my problems are in the that the clutch bites like a shark, and the only place left for slipping is in the belt. A bit frustrating.

[ThomasTPFL]

It looks like a Puch clutch.