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Post by 90GTVert on Jul 1, 2012 11:56:17 GMT -5
Best thing I can find is a nearby back road with a straight stretch 0.3 miles long that changes elevation 3ft over that distance for less than a 0.2% grade. There's an unmanned produce stand (honor system) in the middle of it, so they'll probably think I'm casing the joint as I ride back and forth so I can steal some squash or something. lol
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Post by 90GTVert on Jul 1, 2012 12:47:13 GMT -5
Now I'm really lost. I jsut went to try a test run. Of course the wind had to pick up to throw things off though. With a tail wind, just over 18 seconds all stock. Pretty much where I started out all stock since I figured about a mid 18. What in the hell? I did clean the whole CVT jsut to be safe and regrease when I went back, but I didn't see a problem. I wouldn't think it was dirt or debris since 2 different TDs, both cleaned and greased prior to install, had the harsh drop off on shift. So now I'm wondering if if it just doesn't like a stiff contra or if the sliders are disagreeing with the new contra's shift or what. Being this close to where it was, the good news is maybe I won't have to redo as much. Just gotta find out what exactly the fresh TDs don't like.
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Post by reveeen on Jul 1, 2012 17:48:15 GMT -5
I must have missed the part where you installed a "stiff contra" for a reason?
Usually I find, with the standard contra (spring)(750?), 3.5g rollers to be almost ideal.... making 4.5g sliders about right for a standard contra.
Sometimes it seems to be the luck of the day thing going on..... at 4:30AM it was 80km (50mph) all the way to work, and only slightly slower coming home at 12PM this morning/afternoon. Some days it seems to be hard pressed to hit 65km (40-42mph).
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Post by 90GTVert on Jul 1, 2012 19:00:30 GMT -5
It's somewhere earlier in the thread, but 2 reasons for the contra really. And yes, I like the softest contra that works too cause it's so much easier to work with.
1) I had no 3g sliders and I like sliders. If for no other reason longevity. I tried 4g sliders instead of the stock 4g rollers, RPM did not change enough. Although everyone seems to like 1g heavier sliders, it just doesn't work for me. I dunno if it's because I'm heavy or because I actually monitor and record my RPM?
2) Thinking ahead in the project, I wanted to be able to move down in roller/slider weight for adjustment should it be necessary, even if it wasn't at the time.
I'd call a 90cc contra a 500-750 by the way. By my understanding of the contra ratings, it's an RPM increase. If that's the case, wouldn't a stock be a 0? I dunno. It doesn't matter because I have about 4 1000RPM contra springs and their actual stiffness does vary. Just like my beloved (sometimes lol) Chinese scooters, or life, or a box of chocolates... "you never know what you gonna get". ;D
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Post by 90GTVert on Jul 1, 2012 19:20:35 GMT -5
Turns out it must have been something dirty or a piece of debris or something causing all of my troubles. After the stock setup did so well, I decided to swap back to what I had been using. 1K contra (minus the torsion control), 4.5g sliders, modded clutch. Ran well. I'll be damned. My best guess would be perhaps something was in the part of the rear sheave where the torque driver rides. I used that with each TD I tried. That's just a guess though. Whatever the case may be, I'm quite glad to have got it back both so I don't have to do so much stuff over and because I did not enjoy mid 20 second 0-35 performance. I couldn't wait to get off of the scooter after my ride last night, and that's unusual for me. The setup I had actually used prior to all of this was 5g sliders, but I had been using 4.5g to make up for the shift. Since I'd be swapping some stuff around and rollers vs sliders was on my mind again, I did a pass with 4.5g and 5g rollers and sliders both and got video so I can time them. I also made notes of RPM drop at shift and RPM at 40MPH. The drop is a good indicator of how quick it will accelerate and for best cruising I need to be right about at 7500RPM at 40, a little under and it will push up above 40 more often. Too much under and it struggles at cruise speeds. Over that and regular speeds may decrease, but it does fight inclines or wind a bit better. The video is just being loaded to my PC for editing. Here are some results "on paper" for now. Weights | RPM After "Shift" | RPM @ 40MPH | 4.5g Rollers | 6,700RPM | 7,600RPM | 5g Rollers | 6,300RPM | 7,400RPM | 4.5g Sliders | 6,900RPM | 7,600RPM | 5g Sliders | 6,600RPM | 7,400RPM |
You can see that they act about the same at cruise speed for me, but the sliders keep the revs up past the shift better than the rollers. The usual stated 1g heavier would put me out of the powerband at cruise, although it may match the rollers at the shift... but that's not a good thing in this case. Video at 11. <---Don't hold me to that. I deleted the really slow video. Figured I had lots of slow times coming. Glad I don't, but I wish I hadn't deleted it. It was pretty pitiful. |
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Post by 90GTVert on Jul 1, 2012 21:55:10 GMT -5
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Post by 90GTVert on Jul 2, 2012 7:39:55 GMT -5
I thought I'd go and see if the time changed while I had a chance earlier this morning, since it's running slower than the last time before the new TD. That didn't work. It's so humid the engine is running cooler than it should and missing a little power. I'd like to still try it as-is at the other test spot I was using to see if there's really much difference. I don't think there is. I think it's just slower from the shift dropping off more and possibly the very hot weather.
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Post by 90GTVert on Jul 3, 2012 13:23:07 GMT -5
I was hoping to start getting stuff done faster but I can't seem to even get a consistent result for the setup as-is with this weather. Times vary by 3 seconds in the exact same spot now with no changes to the scooter. Just depends exactly what the weather is like.  On a cool night I may get no fade in the trans, on hot day it's almost immediate. Humidity and temps swing wildly, depending when I can get out to ride. Tuning simply to go faster is so much easier than trying to show changes on paper. |
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Post by reveeen on Jul 5, 2012 8:39:01 GMT -5
I was hoping to start getting stuff done faster but I can't seem to even get a consistent result for the setup as-is with this weather. Times vary by 3 seconds in the exact same spot now with no changes to the scooter. Just depends exactly what the weather is like. On a cool night I may get no fade in the trans, on hot day it's almost immediate. Humidity and temps swing wildly, depending when I can get out to ride. Tuning simply to go faster is so much easier than trying to show changes on paper. Welcome to the wonderful world of 50cc. (you notice condition changes more than you would with a bigger displacement) |
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Post by 90GTVert on Jul 5, 2012 8:39:37 GMT -5
I've been messing with the filed variator fan / fixed half again. I thought since I saw poor results after swapping to the new TD on the last test, perhaps the problem was more the new TD with all the issues I had. Turns out it's still a kind of similar result. Kind of a "meh" mod. It's OK with it or OK without it. No matter what gearing I get into, the engine doesn't wanna pull me faster on any regular basis. It does drop RPM on the shift, but it's not really much worse than stock if I compare the drop to the RPM at 40MPH. It leaves harder in a deeper gear, but it also overrevs out of power at times. If the angle was just right, I'm certain it could be an improvement. It'd be quite a chore for the avg person with a hand file to get precisely the angle they want though and I don't know exactly what it would be. Even if you do get the right angle, at this point stock power will limit speed more than drive face angle, or at least it does with a heavy rider.
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Post by 90GTVert on Jul 5, 2012 8:44:58 GMT -5
Welcome to the wonderful world of 50cc. (you notice condition changes more than you would with a bigger displacement) Yeah, I'm sure seeing that. It really doesn't help with the current weather. Today is 100 so the heat will kill performance to a degree. If you let it cool off then the humidity goes really high and again kills performance. I rode yesterday morning and with a slight headwind and higher humidity hit 28MPH on a tiny hill. I was pissed. lol That same hill in similar conditions with the 103cc in there I might slow to 50. |
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Post by reveeen on Jul 5, 2012 8:55:27 GMT -5
There is a time (here) right after supper (7-8pm?) that it cools and the wind drops off.......... I will volunteer that the ideal conditions (again, here?) happen around 5:30-6:30 AM.
I myself am in a bit of a, well, *thinking* time. Do I build this Zuma, or do I just slam a 150cc GY6 motor in it? It's all about the same to me. Looking ahead, I will be re-locating to a rural spot, I'm not sure anything less than a 150 will be much good to me.
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Post by 90GTVert on Jul 5, 2012 10:07:20 GMT -5
I love 2Ts, but the GY6 would end up with better fuel economy and probably less problems if left stock than you'd see with the modded 2T. For fun's sake, the GY6 just doesn't feel right though. Great low end and then just when I think it's really gonna start pulling... it's out of power/RPM. That's what always gets me when I've rode 150s.
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Post by 90GTVert on Jul 5, 2012 22:03:36 GMT -5
I started playing with ignition timing again. The video should tell the story pretty well.
I've got a new piston on order. I'll set timing to 16 BTDC @ 2,000RPM once the new piston is in. |
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Post by tygertung on Jul 6, 2012 6:07:23 GMT -5
I must do some testing on my Suzuki to see what effect changing the ignition timing has.
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