Who ya gonna call?

[90GTVert]

Jun 18, 2010 8:24:45 GMT -5 Fox said:

The only reason is should break is if you overload it, jump it, or hit a pothole or a speed bump too fast.

How about a 300lb man doing wheelies and riding it offroad?

I'm not sure how effective it is, but I do think the cover could provide some extra support. I always end up taking things a step too far. Regardless, I'm gonna leave it and if my case breaks in half... assuming I'm not killed in the process... I'll be sure to share that and you can draw your own conclusions on whether it was the lack of a proper cover or whatever stupid thing I was doing at the time.

[Fox]

Well, after all you've done to it if it still cooks belts then I would think a hole can be drilled in the fan shroud and some kind of custom tube can be attached to the front side of the cover so air is blown directly over the variator. It wouldn't have to be more than an inch in diameter and I'm sure the fan puts out plenty of flow so the cylinder won't get any hotter. The air that blows out of my fan makes a clean spot on the ground if revved in one spot like a leaf blower so I'm sure it would work.

[redorchestra]

seems unlikely that it would split. I think most stress is on the engine mounting point and the rear shock. If it was a true leveraged swing arm maybe it could break. but the weight its transferred to the back of the case.
I don't think heat is an issue, I think your belt is off centre.
Instead of a straight pull on the belt, you get a diagonal torsion.
Do you have a laser?
Try using a laser to ensure the front and rear pulleys are dead on.

And watch this video if you haven't yet.

[duosport]

I too was wondering about the off center thing. The reason I wondered that was there was a tutorial in the tech section making reference to taking the washer and spacers and putting them to the inside of the variator to the engine side. I was thinking this was changing the geometry of the pulleys.

[2strokd]

Yep...Works great for getting that extra MPH or ten.
I will post if my belts start to go quickly from the same mods.
I shaved the inside of my stock vari,s pully faces flat. Shaved 1/2mm off of the drive boss.
Put spacers every were they can go....I havent had a problem yet.

[90GTVert]

It's been a bit since I updated this situation. We keep having 90+ degree days with 100+ degree heat indexes. I'm not a hot weather person, so I've been less than motivated to do work for "fun". I do have a bit more info though.

I discovered that with all the spacers to effectively elongate the drive boss, I am allowing the ramp plate to travel completely off of the guides. I beleive that is why I have had so much trouble with breaking the bushings on the ramp plate and it can't be too great for any part of the variator to have to grind it's way back into alignment.

I discovered that I can only use one 1mm spacer washer the diameter of the drive boss and be able to keep everything together. That's right on the edge of the guides/bushings, but it does stay together. The problem is that the belt won't ride very low in the pulley with just one spacer and I don't get that steep gear ratio for takeoff. It probably wouldn't be an issue, but I ask my scooter to carry a lot of weight.

I ended up using one 1mm washer the size of the drive boss and 2 washers larger than the drive boss totaling 1.5mm. The larger washers are basically like the restrictor washers found in stock scooters. They allow the belt to travel farther inward, but they keep the pulleys separated farther at their max travel and won't let the belt ride as high.









I am once again seeing the light markings from the washers on the inside of the belt, but it appears to be causing no real harm. It should be no worse than restrictor washers in a stock CVT. The only bad thing is that my max speed is now just under 48MPH. I will end up tinkering more, but for now I'll take a little less MPH for much better acceleration from lights and such. So far I have rode 100 miles with no evidence of eminent doom for the Bando belt. I would have added a few more miles, but I had a few issues on my last ride.

I was riding along and my exhaust got a lot louder. Not gradually, but like a switch. I stopped and realized that this had happened. No big deal, I can weld it back on. It's my fault. For some reason I removed the muffler support a long time ago. Oops.



I pull away after picking up my muffler and within 200ft I start to feel drag and hear grinding in the case. "Now what?" I limped it home kinda slow and found the case bearing was destroyed. I've got one on order now. It had been making a little noise or some time, but it was nothing alarming.



I think I am on the right track with this scoot. I'm gonna have to get back to the SunL and see if anything's fishy with it still. At least I can say I have learned from this, so it's not a totally bad situation.

[drawkward]

Please link me to your case bearing! I've been looking for weeks.

[90GTVert]

Yeah, they are tough to find. It's 8x28x8 638X2-2Z and most people have quit carrying them. It looks like MRP carries them and I got them from A&J Parts.

Looks like #19 here to me...
www.kaseaparts.com/skyhawk-90-quad-crankcase-c-24_117.html

Here's what all the MRP dealers sell...
www.kymcoracingparts.com/SPD/qj-638x2-zz--80000FA0-1241537585.jsp

I found a ceramic version while searching last night too, but it was about $100.

[Goosey]

Will a bearing puller wreck those things If I wanted to pull the old ones from my old dead engine to keep as spares?

[2strokd]

I have bought em off ebay before for cheap.
Cant seem to find any now! I could use a couple myself

[90GTVert]

You'd want to press or tap them out by applying force to the outer edges of the bearing rather than applying all the force to the center like you do with a blind hole bearing puller necessary for these.

[90GTVert]

I welded my stinger and silencer back on, but still no support yet. I had to cut the inner part of the shot bearing from the drive gear that the clutch rides on.

I also decided to remove the starter clutch and other electric start gears. I normally have terrible luck with kick starting, but lately I have been OK. The battery is shot now anyway, so I figured it's worth a try.

I ended up using 2.5mm of washers to compensate for the room the starter clutch took up on the crankshaft. (Only 2mm shown here.)


That's a pretty good drop in weight that the crankshaft has to spin.


I fired it up and it seems like it revs a little faster now on the center stand at least.

[drawkward]

Thanks for the links. Bought one from the first link. If all goes well I'm going to stock extra's. With all the dust these bearings don't last very long. I've already destroyed two case bearings.

That is definitely a significant drop in weight. I mean people go to all the trouble to get inner rotor ignitions for the same purpose, right?

[90GTVert]

I also ordered 3 of those bearings. Ends up cheaper in the long run not paying shipping over and over anyway.

Yeah, it's removing rotating mass just like lightening the flywheel or inner rotor ignitions. I'm nevrous about it already, but if the kickstart does break on me it won't be the first time I've had a tow home by a long shot. lol I notice that lots of folks seem fine with the minarelli kickers. I think I'm just a big dude and kicking it too hard and destroying them. I've been trying to be more gentle lately.

[Fox]

I think what breaks kickers is when you kick it on the down stroke. The ratchet gear has no pre-load on it so it engages harder. I always work the kicker til I feel compression and then let it come back up to the top and gently push down on it before kicking it so the ratchet gear is engaged prior to the force being applied. I also have my kick lever installed closer to a 2 o'clock position rather than three o'clock so I get a little more travel each kick. I suppose BBK's call for even more force which can't be good for the kicker. From what I've seen the case where the gear shafts pivot is what cracks most of the time.