just went out for a frickin fun run around the savannah and blew the cvt apart. And today is the last day of work for the year. Lesson here, don't relieve the ramps in the variator too much, lol especially if you have one that doesn't follow the roller/slider to the end of the travel.
That sounds like a great build, I've toyed with the idea of just adapting a straight up centrifugal clutch and shoot for one ratio, but obviously it has its draw backs compared to a varied setup. I do prefer my odds with a chain compared to a belted CVT though, I'm not sure exactly how much we lose with the belt. I'm no go kart expert but I believe Noram and Bully make some mean clutches that are tuneable. I even thought about either making my own or adapting a manual clutch to run a single ratio.
Damn these guys are rootless in here just machining the bore a bit, they didn't even taper it in. CV's are some of the smoothest transitioning carbs ever. I'll never trade it for a slide carb though, lol. Hey Kachi, that exhaust looks killer and since you said it has the baffles inside, I won't mind throwing some cash at it for some kicks.
Yeah, I can see the difference, color me impressed, my friend. I will never say you didn't help me out with a lot of further education about these scooters. Hey Piston, is it possible I use a document that I got from you in one of my video's. It's the chart of the cam performances. When the weather breaks in 10 years I will be throwing in an A9 cam because of your education when I got that A14. You know I'm gonna shout you out in the video, but I didn't want to post something like it was my idea. What do you think?
Something that makes these sorts of measurements and comparisons difficult is that these CVT's have no sort of "position memory" after handling if you will. If you spin up the CVT and spin down several times it will take a similar position set (level of the sheaves where the belt rests), but if you were to remove the belt and reinstall, it will likely take a different position than it had before you removed it. I found from experience that after any sort of adjustment or handling you need to exercise the CVT by spinning it up and down to have any sort of accuracy of position. I guest there is also a possibility that the driven pulley Torque Sensing pins / slots could be the limiting factor. I've been trying to envision what would happen if the pins were removed and the CVT was spun up for testing. Probably have to have the wheel off the ground because any sort of load would cause the moveable sheave to freewheel. But if the belt actually traveled further in the pulley's then that would suggest that the slots are the limiting factor. Then maybe extending the slots would be a viable option.
I looked up the Comet brand of CVT's. Their still around in some form and big with the go-cart conversions. Seems like they deal with the China copies also. Those kits are physically sized somewhat between the snowmobile and GY6 CVT's. The Comet is more of a proper design than the GY6. There is a 30 series kit that is asymmetrical and would probably be the best option. You would have to use some of the kit and have to make up the adaptors. That would be an interesting project. https://www.gokartsupply.com/tavapp.htm
Hers a closer look at the Step. it fooled me till I received the Nibbi 26mm as my Caliper jaws would not go that far inside I used Telescoping gauges to measure.. Now look at the True 26mm from Nibbi, No machined Step (second pic). The FAKE measures 24mm in the center and the Nibbi measures 26mm....
Nah its FAKE, Look at the machined step on the FAKE carb on left. the end measures 26mm but the Center of the Venturi is STOCK 24mm. They just bored the end out off a 24mm carb and called it a day.. the 26mm Nibbi I got from Dan is a True 26mm carb but some jets are different so I didn't source the jets.
Hey BCY, Yeah I'm a TOCE guy, gonna look killer coming out the back of my future CBR600, but for now, this will do. Yup, silencers in them and doubt I will ever remove them, I'm not into a lot of noise, gotta here my music. Think I will stay with the CV, I have a lot of homework to do on the round slide or flat for that matter. Hearing tuning horror stories. I will add a link for both to the video, once produced. I WANT TO RIDE!!!
Great write bud, seems like your heading in the right direction, Snow performance use to build a water injection kit for my Cummins diesel, read lots about it but never did it, I was interested as it dropped exhaust temperature when towing and pouring more fuel to it, egt, s are a killer on diesels.
Got damn, its been a while and I have done some poo. trying to wrap up work and do some business on the side has stripped my time to a minimum. I grenaded a belt on the highway doing about 125km/hr. Was on a long downhill. lets pull back 2 days before. I took a head from a 125cc engine, ported it and matched the intake and exhaust. just blending etc. The valves are much smaller and I dont care. the valves also sit closer to the piston and I rushed the job. started it and slapped the poo out of the piston with the exhaust valve. No worries, I just pulled it back down and shaved her some clearance. Valve didn't bend and it was back together. I unshrouded the valves to try to maximize the flow and ease the compression. It knocked once the CDI brought in timing so I limped to the gas station and poured a full bottle of octane booster and topped up with 95. Gave it a little jiggle and went on my first group ride. I dont have a working speedo on my scoot so I sometimes us the gps on my phone. I have realized that it isn't calibrated well and alomst all the times in a number of vehicles reads 8-15km/hr low. Anyway, we hit the southern highways and my buddy had his water cooled 150cc scooter CPI GTR with 17" wheels. He normally hits 135-140km/hr at the top. we had a few fun runs, I thought he was pulling back and later found out he was flat out and I was right on him. The quickest downhill run we did he said he hit 145 and I was next to him, so I'd call that a good 130-135 for me safely. The engine did ping with the excessive rpm on the downhill runs, so I had to pull back. Man it was fun, the guys with the bigger bikes were amazed that we picked up and moved like we did. I did pull the silencer from my can to lean out the mixture, I know I am normally rich at the top. I had to leave the group to head back home and fragmented the belt on a downhill, i didn't take into consideration the amount of heat and abuse the belt took on the way down. Futhermore I previously abused the belt by using a NCY non-fan fixed variator face and over heated the belt. This more than likely lead to the failure. Anyway, it briefly locked the back tire until it was able to shred the belt and free wheel. It was definitely a skid mark worthy moment, lol. Had to get her home on a van and changed the belt out for a Gates. The belt was less than 5 months old Bando brand. But I ride everyday, so I know its my own fault. PS dont be like me. So even now the higher compression engine is soo much more enjoyable in the mid range. I can still kick start it. I did fabricate and install a new kick start stop, since I broke the old one off the case. I have pictures of everything, I'll try to upload later tonight. Even with a full tank of 95 I cant run up in the rpm's without spark knocking. It doesn't matter right now cause I am stil able to pull up to 110-115 without knocking. I just have to be really careful with the throttle. I will try to get some video and sound of it for you all to hear. I also sent a 150 head to the machine shop and got it shaved a few thou to raise compression while still having the big valves for better flow. will see how that turns out. The goal is to find a good balance of compression and performance without reaching the limits of knock and fuel. I'm also trying to get a water injection system to help with the knock up at the top, but I dont want to get too complicated. we dont have E85 and methanol is expensive down here.