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Post by drewzard6688 on May 17, 2022 18:51:26 GMT -5
So. Lots of fun trying to solve this. Been taking it slow and off wot top speed stuff to keep temps down. I tried the Oem 64 jet to see if the wideband would react predictably. It did. Little too lean for my taste lol. Put in a 67.5 because the 70 I tried was still a little Rich. The 67.5 has the best afr I’ve seen. Max temp 339°f. Didn’t go wot very long. It’s fast on the pipe but not if you end up in the lower rpm cruising and you get on it. It’s a decent acceleration but not like on the pipe. Will tune the cvt more when i have the carb dialed in. It’s rideable. Feels sluggish after a long ride, I’ve put 40 miles on it just keeping it 35mph and under, no more seizing yet. Will probably put a few more hours on it lower speeds. The thing heats up fast as soon as you get past 8k rpm Here’s the plug formerly brand new plug after todays ride imgur.com/a/8xkGizg
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Post by drewzard6688 on May 18, 2022 20:18:02 GMT -5
It’s still a pain! The 67.5 jet got a little too warm, wot gets to 330°f quick and never seemed to slow down before I decided to let up. I’m thinking it’s possibly just a combo of higher rpm and the new bore not broken in. Seemed to have pretty good power. I don’t recall it bogging but I pulled home pretty shortly after I left.
Put a 72.5 in and it was pretty rich. O2 says so, my ears do too. Ran decent the first few miles then bogged down at 6900rpm. My cvt doesn’t even shift till 7700rpm. If I hit a downhill it will get on the pipe at 7500 and take off again.
Put a 70 in and it was pretty much the same. Bogged down after about 6 miles of riding. 6900 rpm wall. When it’s in the bog it will take off if I get a down hill.
I could jet it lower and watch the temp religiously. Or drop the weights. Last time I ran the 4g with the 72.5 it was happy to rev fast. I don’t remember it bogging ever but damn it was way to easy to end up in the 10000rpm+. That was with the a plus 15% torque spring I believe. It’s had the stock in for a while now though so maybe the rpm might be lower.
I’m running a mix of 5.5g and 4g sliders for 4.75g. I have 4g, 5.5g, 6g, 7g sliders.
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Post by Zino on May 19, 2022 12:47:00 GMT -5
Your jetting is close I think you have snappiness to pick up with balancing the cvt For me the yasuni r power band only had about a half gram of range that worked best for top end and snappy power when I hit the throttle. 5 .5 grams was best 5 was too light and 6 was to heavy I found I was targeting 8500 -9000 rpm’s that I want the rpm’s to jump too and hold when I hit the throttle wide open and then at about 30 mph the variator would finish shifting and then increase to top speed
As far as take off 5500-6500 is the target for clutch spring strength which was medium or hard springs
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Post by drewzard6688 on May 19, 2022 14:36:20 GMT -5
Been running the yellow springs on the stock clutch. I’m gonna try putting one jet smaller in and seeing if the 6900rpm bog comes back. Would anything overheating in the cvt cause such a weird rpm “wall” that it can’t rev past? My clutch engages around 5500. It’s always spiked rpm on take off and then settled back after you get to about 10mph, I’ve always assumed it was just the stock clutch attempting to grip, changing springs, weights, and belts never makes it go away.
If any other noobs are here and reading this I would say: 1. The yasuni r pipe is awesome but maybe a bit too high rpm for true street driven bikes. 2. The stage 6 street race cylinder is perhaps more trouble than it’s worth with the incredibly tight tolerance. Maybe it’s better with a more conservative pipe. 3. The trail tech temp gauge is the only one I’ve tried worth getting. The Amazon cheap stuff is a waste for temps. Fine for rpm. 4. The polini hi speed variator is decent but I would probably go malossi next time.
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Post by Zino on May 19, 2022 17:56:56 GMT -5
The bog you might be feeling is when the dual angle torque driver kicks in . You dont notice it with a stock bore or a upgraded bore with a stock or street pipe because the power band is so wide and you have power through the shift.
The vinos stock torque driver has a dog leg on it so it shifts slow at first and then up shifts fast into high gear . With a narrow power band pipe you might drop out of the power band for a second until the rpms catch back up .
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Post by Zino on May 19, 2022 18:05:32 GMT -5
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Post by drewzard6688 on May 19, 2022 18:15:44 GMT -5
Dropped the 67.5 jet in and I like the AFR's but she just every so gently seized on a WOT run at 361* F.
And the "wall" it won't rev past is still present at ~7000 rpm.
I'm going to pull the jug, go a little more aggressive on the port chamfer/finally get a flex hone. Will take the feelers out and check wall clearance like a responsible adult. I'll shoot for the .002 clearance Corrosion had good luck with. .003-.005 should still be good too...
Edit, it’s not so much a bog as much as it will stop revving up past 7000 after it gets a few miles on it. I know it’s not temp of the engine because I can see that in real time go back down but the power will be gone even when temps end up closer back to idle. The quick takeoff rev spike feels more like a slipping clutch or belt but the belt looks good, pulleys look good, it does it with a Oem belt or polini Kevlar. No matter the weights or the clutch springs. I’ve always assumed it was the 2 pad Oem clutch just not having enough purchase to handle the power.
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Post by drewzard6688 on May 24, 2022 19:22:38 GMT -5
I’m getting tired of this street race kit fighting me. Anyone have a recommendation for a 70cc daily reliable kit I can just slap on and run? What’s got a good reputation?
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Post by Zino on May 24, 2022 20:15:30 GMT -5
I run Malossi cast 70cc on both my vinos Both have 1000's of miles on them stock carb 70 mikuni . They turn 9000 rpms at there peak with the malossi wild lion street pipes . Your pipe might be overwhelming the stock carb .
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Post by drewzard6688 on May 24, 2022 20:53:45 GMT -5
When the carb is tuned to good afr, good looking plug, and good top speed, throttle response, power (but causes the heat to rise quick) it runs fine with the stock carb. I jet it for a lower temp and it’s gurgling rich.
I’m moving this week and going through personal drama, so it’s going back to 49cc for the time being. I need a reliable scoot asap.
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