Post by humanshield on Feb 3, 2015 15:14:36 GMT -5
So, I went through the time and expense to change my 49cc scoot to an 83cc monster
I'm still pondering removing the 83cc motor and putting the 49cc motor back in for a major improvement. But I'm not there "yet".
The scooter bounces around and vibrates really badly with the 83cc motor to the point it's not enjoyable to ride.
On the rear stand, with me standing beside it revving the throttle, it will vibrate so badly that it will move at 2 mph backwards on the stand just from the vibration.
To make sure this isn't a really bad wheel imbalance, I'm going to balance the rear wheel then add ceramic balance beads to it.
The carb has been re-jetted to 95 and this scooter ran great before the change. Which should eliminate most other problems such as coil, CDI, fuel etc. I also raised the carb needle by lowering the clip to the bottom. JIC. The valve timing and adjustments have been checked and verified to be spot on.
Now she tops out at 25-27 mph. Before, 35 was pretty easy. Heck I used to even hit 45 on occasion depending on the wind!
In the process of installing the BBK, I installed a new variator assembly, new drive belt AND a new clutch assembly. The clutch was seized. The variator was marginal.
Anyway, both new now.
The belt was really hard to get on. I mean really hard. I had it on the clutch first, squeezed down into the groove as far as it could go and then (and only then) would it JUST BARELY slip over the variator shaft if I squeezed the belt down small enough. To me it seems too tight.
So I checked with the Service Manual AND called the factory and both say it takes a 669 belt. So that's what's on it.
If the belt was too tight, it seems it would tend to stay centered on the pulleys rather than change orientation as needed for top end.
But I'm just speculating. It tends to grab really early now with the new clutch and pulls reasonably strong up to 25 (about like before when it was 49cc, maybe a tad more) ....then it totally stops accelerating at 25.
At this point, I would call this venture into BBK's a disaster. But I'll keep at it for a while longer. Then we go back to the 49cc motor.
Four Questions....
1). Could I need an even larger main jet than 95 for this 83cc "monster" :-)
2). Is it possible that the belt IS too tight and that would limit top speed?
3). Is it possible the belt just needs time to "break in" and it will improve over time? I've read that others had that experience.
4). Since this is actually a different motor, could it just be a badly imbalanced motor internally? Could the BBK have thrown it this far out of balance? The piston is probably heavier after all.
I'm still pondering removing the 83cc motor and putting the 49cc motor back in for a major improvement. But I'm not there "yet".
The scooter bounces around and vibrates really badly with the 83cc motor to the point it's not enjoyable to ride.
On the rear stand, with me standing beside it revving the throttle, it will vibrate so badly that it will move at 2 mph backwards on the stand just from the vibration.
To make sure this isn't a really bad wheel imbalance, I'm going to balance the rear wheel then add ceramic balance beads to it.
The carb has been re-jetted to 95 and this scooter ran great before the change. Which should eliminate most other problems such as coil, CDI, fuel etc. I also raised the carb needle by lowering the clip to the bottom. JIC. The valve timing and adjustments have been checked and verified to be spot on.
Now she tops out at 25-27 mph. Before, 35 was pretty easy. Heck I used to even hit 45 on occasion depending on the wind!
In the process of installing the BBK, I installed a new variator assembly, new drive belt AND a new clutch assembly. The clutch was seized. The variator was marginal.
Anyway, both new now.
The belt was really hard to get on. I mean really hard. I had it on the clutch first, squeezed down into the groove as far as it could go and then (and only then) would it JUST BARELY slip over the variator shaft if I squeezed the belt down small enough. To me it seems too tight.
So I checked with the Service Manual AND called the factory and both say it takes a 669 belt. So that's what's on it.
If the belt was too tight, it seems it would tend to stay centered on the pulleys rather than change orientation as needed for top end.
But I'm just speculating. It tends to grab really early now with the new clutch and pulls reasonably strong up to 25 (about like before when it was 49cc, maybe a tad more) ....then it totally stops accelerating at 25.
At this point, I would call this venture into BBK's a disaster. But I'll keep at it for a while longer. Then we go back to the 49cc motor.
Four Questions....
1). Could I need an even larger main jet than 95 for this 83cc "monster" :-)
2). Is it possible that the belt IS too tight and that would limit top speed?
3). Is it possible the belt just needs time to "break in" and it will improve over time? I've read that others had that experience.
4). Since this is actually a different motor, could it just be a badly imbalanced motor internally? Could the BBK have thrown it this far out of balance? The piston is probably heavier after all.