Adventures in CVT By evilgenius (Read 1,975 times)

[evilgenius]

So I notice one morning that my rear axle is still engaging after the enricher shuts down. Didn't think much of it at the time, wrote it off to carb idle setting needing adjusted due to the fact that it's no longer a bazillion degrees on a daily basis here in beautiful KY.

Rode it for a few days, then went to adjust the idle down...to my great dismay I found that there was no idle setting low enough to not engage the axle and keep the engine running. R'uh-r'oh!

Sure enough, the clutch was staying 'grabbed' at virtually all RPM. Pulled the bell off, and a chunk of pad and a spring came out with it. Not good. Looks like the shoe snapped right around the 'bottom' hole. Steel looked to be of terrible quality! End result:spring pulls other end down, extending the rest of the shoe out and engaging with the bell all the time.

First thing's to get it off. After reading and watching the videos, I go and buy a 'rubber' strap wrench from Autozone to get a firm grip on the clutch bell.



Never do this. This tool was a complete and utter POS. It came, it grabbed, it snapped. End of story. Need a jar opened? Maybe. Not for this app, though. Might as well have used the old belt to grab with, it probably would'a held up better anyway.

Next came the chain wrench. I'm pretty sure these are just the evolution of some mideval torture device. Still, the axle nut would not break. There appeared to be some yellow dabbed onto the end of the shaft - I first took this as a 'witness mark' that the bolt had been torqued properly, but maybe it was kryptonite-enhanced loctite. Tough to say. I took a torch to it - nada. Stood on the damn thing with an impact - no dice. Penetrating oils, mineral spirits, P-B blaster...I threw everything I had at this thing and it just sat there and laughed.

Finally, I resorted to the method of last resort - I summoned the Evil Wife, who hopped up, laid on both brakes, and held the scoot in place while I heaved at it it with a 4" Impact socket on an 18" breaker bar fitted with the "BFB" - a 3 and a half foot section of cyclone fencing pipe. As Archimedes posited, "Give me a lever long enough...and I will move the world single-handedly." Finally, the nut came loose and off the assembly came.

The OEM Bando 835 belt was fairly worn, but still good for a backup. With an eye for tuning, I thought I'd pull the variator and see what kind of weights were in there. Being fairly resourceful, I fabbed a sturdy-looking little variator tool:



It would seem that when Wang hit this thing with the pneumatic at the factory, he had the torque set to the same "WFO" setting used on the back axle. Result: variator drive face breaks into chalky bits. No kiddin'.

To it's merit, my tool did not fail. The chunks of 'Chi-luminum' variator still bound to the pegs will attest to it's construction.



What IS this thing made out of? Fired clay?



So that bridge is pretty well burned - one way or another, this variator's coming off! Tried the chain wrench - no go. Kept slipping off, or breaking more of the paper-mache-like fins.



Tried bracing it with a board while I cranked on it with the BFB, to no avail. Variator ate the board.



Subjected the nut to the same barrage of tactics as the clutch axle, with the same predictable result. Eventually, I resorted to a BFH and a sturdy chisel, with which I reduced the drive face to the physical equivalent of a big huge nut, and broke it with the BFB and chain wrench securing the remainder of the drive face.

On the positive side, I did finally learn that I've been running on a set of 12.5g rollers. An important little piece of data, that.

So...time for parts! After lots of browsing, I finally decided on Battlescooter's GY6 variator kit, a gates powerlink 842 (also from B-S), and a 'mystery clutch' from ebay that turned out to be a fairly sturdy-looking 'yikelup' brand clutch assembly.

www.battlescooterstore.com/sess/utn;jsessionid=154c9531fa163fc/shopdata/0137_GY6+150cc/product_details.shopscript?article=0170_Complete%2BRacing%2BSpeed%2BVariator%2BKit%3D2C%2BTGB%2BLaser%2B%3D28GY6TK%3D29

Battlescooter got me my parts over the weekend, ebayer took 'till the next week.

Following the impeccable logic handed down by Haynes manuals to all would-be wrench turners, "installation is reverse of removal". Clutch assembly went on without a hitch, as did the variator assembly (sticking with the 12.5g rollers). Rubbed a dab of moly grease into the steel inside the sleeve of the variator so that hopefully it'll self-lubricate over time without gooping anything up. Decided to skip on those red springs for now. The battlescooter guy said that basically the color had nothing to do with actual specification - they just wanted 'em in red. Nice. Rather than go to the effort of putting on these 'mystery springs', I figured I'd try what's in the clutch I bought. Especially if they are uber-torque springs, I'm not sure I want to take that big chunk out of my available powerband. Curiosity project for later, or potential "re-bay" materials maybe. Got some new nuts and washers, torqued both to the neighborhood of 40-ish foot pounds, and let the loctite cure overnite.



From an engineering standpoint, this variator looks pretty sweet. Feels to be some higher-quality metal here, for starters. Variator face is a gargantuan 118mm. Variator face has been shot blasted, providing what is no doubt a very aggressive grip on the belt. Ramps look good, with lots of extra travel path cut right to the end.



While amongst all this, I also sealed up some cracks at the angle where the snorkel meets the air box, and replaced the blow-by hose to the airbox with some higher quality hose. Also changed the gear oil, which had been cooked to a nice crispy black from pitting the gears against the 'always-on clutch' too.

Put it all back together, crossed my fingers, and...success. Everything fell right into place. Adjusted the carb...oh yeah...she's purrin' nicely now.

Back on the road, everything seems to be just fine. Started out slower, and then got a little more ballsy as I got more confidence that everything was playing together nicely.

So...what everyone is of course asking at this point: what are the results? Well, going from a non-working scooter to a working scooter is a huge plus. I still have yet to GPS, but the Chi-nometer that used to say 70mph on a flat-and-level WFO cruise now flirts with 80mph. Factoring in all known variables, I have presumably gone from 55-60 top end to 60-65 top end under ideal conditions, so I will certainly take that. Not sure that there was much change in low-end grunt, but getting to top speed seems more smooth now. Overall, I spent around $130 for everything, so I'm pretty happy from a cost vs benefit standpoint.

And so, for the past 2 days, I have aimlessly rode around in the warm KY sun, with a big smile on my face, being more or less happy. Not having any true end for this saga, I'll just trail off with a few gratuitous pics:

Right side:



Left side:



Of course, man-law dictates that if shiny new parts come with a sticker, that sticker must be applied. In this case, a battlescooter logo:



A little clearer pic of the air scoop, which is still holding up fine:

[Bashan]

Great post, I think we can all learn a lot from it. I would say the Battlescooters decal is appropriate since you certainly did some battle. We had a guy post a while back about not being able to get the clutch nut off. I think as a warning to everyone he had some yellow substance on the nut. I think that may mean they used the Sino-loctite which is like our red loctite, and then some bonehead impacts the hell out of it; so beware if y'all see that. I used a plastic strap wrench from Lowes that worked great but it did actually have some metal parts on it; I don't know if it would have held up against your debacle. Actually, I think it's good all this happened, you caught it and replaced everything before catastrophic failure. Good wrenching, thanks, Rich

[evilgenius]

Thanks for the compliments, Rich! You are right, every time I go to do just a *little* something on this scoot, it turns into a significant engagement. Like you said though, I'm just glad I caught it before the proverbial scheiss impacted the rotational cooling device. Better a week in the garage than an hour on the side of the road!

[ce]

Excellent, excellent.

You have wrestled with the horns of a dilemma, and dashed the beast to the ground.

You are indeed an evil genius.

For improved induction on your scoop, remove the louvres on the fan shroud, and fit a four inch stainless steel kitchen strainer to scoop. The best ones are at The Family Dollar store, and they only cost a dollar.

You'll see how it works when you get one, convex mounting looks awesome, and concave, it looks like it would suck in a small dog.

A utility knife clears the opening easily with a roofer's hook blade.

Then hot glue or epoxy it to the area it fits best.

I used a four inch black plastic roofing gutter elbow from Lowe's that I cut two scoops from.

At least I think it improves induction, when you hold your hand it there, you really feel the cool air drawing in. Maybe yours already does that, but I wanted to remove the louvres, they sure seem to be in the way.

[evilgenius]

You're too kind, ce!

You're not the first person to suggest removing the louvres and replacing them with something else. I took a look at mine when I was fabbing the scoop, but decided to leave them on the basis that A) SOMEthing is needed there, in case I pass by a wayward chihuahua on the side of the road, and B) anything else I put in place of the louvres would likely only be more restrictive, rather than less.

Got any pics of your scoop with the sink screen installed? I'd love to see how you did it. I've looked at a lot of these and it seems like everybody's got their own twists on it.

And yes, just sitting there idling you can put your hand up and feel some seeerious suck action at the intake. Pretty generous southern breeze blowing out the bottom side of the shroud too, I was actually pretty surprised what a difference the scoop made. It's like the difference between blowing out a birthday candle and using a compressed air nozzle - no comparison at all. I'm sure my poor little gy6 appreciates it. Under higher RPM's and ram injection from the air sliding down that body panel, I'm lucky I haven't decimated the local squirrel population just in riding by!