Post by beebo on Nov 21, 2013 19:54:47 GMT -6
I own a couple of motorcycles, a couple of scooters, and they all have a different "feel" to them, and I enjoy riding them all. But this Jonway has always had quite a bit of vibration in it, and it has taken a while to figure out the source(s) of the vibration. The first thing I suspected was the tires that came on it, very soft rubber and kinda lumpy looking, and howled like mud grips on a 4-wheeler. They were worn out at 2300 miles, put on some shinkos that now have almost 4000 miles on them with little wear, and that did help some. Then I started noticing a sound, like a bell ringing, when I was idling at a light, kinda sounded like a biker bell or something, so when I got home, I found that the rubber bushing at the motor mount was loose, so I tightened it some, and that made things a little smoother yet.
At the same time I was wondering why this thing was such a dog--both my 150's will easily run off and leave this 250 in the dust! It takes off at 4000 rpm, then settles in at 3500 rpm and stays there until it eventually climbs with increasing speed. My 150 launches at 6000 and settles in at 5500 rpms! So I decided to pull the cover off the transmission and see how much trouble it would be to pull the variator or clutch. I was pleased to see a gates belt from the factory in there, but it was hanging there limp with no pulley tension on it. Also, there were wear marks on the inside or the cover, so I was thinking that the belt was running loose at speed, too. I had it on the stand, so I fired it up and watched the pulley action as I revved the motor, and the belt was flapping around, with about 2" of deflection as it ran! I did a little reading here on site, and got to looking at the torque spring. I was easily able to pull the driven pulley apart to get enought slack to remove the belt. This didn't look right so I ordered a new spring from MPS Racing(a white one) and after finally getting that nut off, put the new spring in. It was about an inch longer than the stock one, but much stronger at compressed(installed) height. I like to never got that pulley to open up enough to get the belt back on! I could barely pull it apart enough to get a screwdriver in the gap and lever ihe pulley apart enough to get the belt in there. No slack in there now! Now the difference a new spring made was enormous! The bike launches at 4500 rpm now, settling in at 4000 rpm, and is so much smoother, It feels like a whole new bike! Very smooth, and the top end went up from barely reaching 70mph to barely reaching 80mph! I don't run at that speed, but it does 70-75 with ease, making it much easier to drive on the interstate, something I do daily now that I can.
I might try fiddling with the weights now, to get just a little better performance on takeoff. It seems like the weights are full out by 30mph(too heavy?) and it is like taking off in first gear and shifting straight into 5th gear at 30. I want something more in between there. I'm thinking around 5000-5500 rpm. I'm not real sure where the power band is on these 250's- Jonway's website says peak torque@5500rpm, peak hp@7500 rpm, but it is the same specs for all their motors. It seems like this longer stroke motor might be lower than that. It certainly isn't tuned for that powerband from the factory. Anyone have some better info on that? Anyone ever dyno'ed this motor?
At the same time I was wondering why this thing was such a dog--both my 150's will easily run off and leave this 250 in the dust! It takes off at 4000 rpm, then settles in at 3500 rpm and stays there until it eventually climbs with increasing speed. My 150 launches at 6000 and settles in at 5500 rpms! So I decided to pull the cover off the transmission and see how much trouble it would be to pull the variator or clutch. I was pleased to see a gates belt from the factory in there, but it was hanging there limp with no pulley tension on it. Also, there were wear marks on the inside or the cover, so I was thinking that the belt was running loose at speed, too. I had it on the stand, so I fired it up and watched the pulley action as I revved the motor, and the belt was flapping around, with about 2" of deflection as it ran! I did a little reading here on site, and got to looking at the torque spring. I was easily able to pull the driven pulley apart to get enought slack to remove the belt. This didn't look right so I ordered a new spring from MPS Racing(a white one) and after finally getting that nut off, put the new spring in. It was about an inch longer than the stock one, but much stronger at compressed(installed) height. I like to never got that pulley to open up enough to get the belt back on! I could barely pull it apart enough to get a screwdriver in the gap and lever ihe pulley apart enough to get the belt in there. No slack in there now! Now the difference a new spring made was enormous! The bike launches at 4500 rpm now, settling in at 4000 rpm, and is so much smoother, It feels like a whole new bike! Very smooth, and the top end went up from barely reaching 70mph to barely reaching 80mph! I don't run at that speed, but it does 70-75 with ease, making it much easier to drive on the interstate, something I do daily now that I can.
I might try fiddling with the weights now, to get just a little better performance on takeoff. It seems like the weights are full out by 30mph(too heavy?) and it is like taking off in first gear and shifting straight into 5th gear at 30. I want something more in between there. I'm thinking around 5000-5500 rpm. I'm not real sure where the power band is on these 250's- Jonway's website says peak torque@5500rpm, peak hp@7500 rpm, but it is the same specs for all their motors. It seems like this longer stroke motor might be lower than that. It certainly isn't tuned for that powerband from the factory. Anyone have some better info on that? Anyone ever dyno'ed this motor?