Post by ron521 on Apr 26, 2010 6:03:06 GMT -6
I took advantage of the nice weather last weekend and installed my 72cc BBK purchased from Scrappydogscooters.com, an eBay vendor.
Installation was very straightforward, the engine came apart easily and went back together the same way. I didn't remove the engine from the frame, merely removed the seat and storage tub, and a rectangular access panel on the "front" of the body, near the riders heels.
I kept thinking how much easier the install would have been if I were doing the same work on one of the old Honda 50, 70, or 90cc motorcycles, whose engines just stuck out into the air, with no body panels in the way. But if I were, the information wouldn't really be relevant on this forum.
I will mention that I already owned a UNI filter, but was not using it. I had tried it with the 50cc engine, and found no difference, even when changing jets. Apparently, the stock airbox can keep up with the airflow generated by 50cc. This is not the case when the engine is 72cc, more on that in a moment.
So I took the now 72cc scooter out for a ride (still with the stock airbox), and was impressed with the acceleration, and some increase in speed. I had the distinct impression that the engine was running a little bit rich now.
I removed the stock airbox, and installed the UNI filter which I had tried before, and found that the performance was very much better indeed, and the perceived richness disappeared. I ended up riding nearly 20 miles just enjoying the scooter on a nice day.
Previously, I could reach 36 mph on level ground, now I can reach that speed with part throttle, and 44-45 mph wide open.
On a long four-lane road with a gentle downgrade, where 50cc would take me to 42 mph, I could now reach 47 mph.
Going UPHILL, where 50cc would struggle along at 29 mph, I now sail up the gradient at 42 mph.
Put another way, I can now go as fast UPHILL as I could previously go DOWNHILL on the same road, with a significantly increased speed downhill and on level ground.
I am completely satisfied with the results of this BBK, and with the transaction from eBay seller scrappydogscooters.com.
In the ad for this particular kit, he was very upfront about the wrist pin being slightly too long (hence the very favorable price). Addressing the issue turned out to be very easy, took maybe 5 minutes to make it fit properly.
He also shipped my order very quickly, I placed my order on Friday, and received the box of parts on Monday. All the parts appeared to be very high quality, at least equal to those which I removed.
And the results are everything I could have hoped for. I'm still running stock jets in the carb (31 pilot and 88 main), and have changed out the variator rollers (originally 6.7 grams, now 5.0 grams).
I will probably experiment with the main jet, and possibly the rollers again, to see if I can break the magic 50 mph barrier.
If so, fantastic, if not, I'm still very happy.
Installation was very straightforward, the engine came apart easily and went back together the same way. I didn't remove the engine from the frame, merely removed the seat and storage tub, and a rectangular access panel on the "front" of the body, near the riders heels.
I kept thinking how much easier the install would have been if I were doing the same work on one of the old Honda 50, 70, or 90cc motorcycles, whose engines just stuck out into the air, with no body panels in the way. But if I were, the information wouldn't really be relevant on this forum.
I will mention that I already owned a UNI filter, but was not using it. I had tried it with the 50cc engine, and found no difference, even when changing jets. Apparently, the stock airbox can keep up with the airflow generated by 50cc. This is not the case when the engine is 72cc, more on that in a moment.
So I took the now 72cc scooter out for a ride (still with the stock airbox), and was impressed with the acceleration, and some increase in speed. I had the distinct impression that the engine was running a little bit rich now.
I removed the stock airbox, and installed the UNI filter which I had tried before, and found that the performance was very much better indeed, and the perceived richness disappeared. I ended up riding nearly 20 miles just enjoying the scooter on a nice day.
Previously, I could reach 36 mph on level ground, now I can reach that speed with part throttle, and 44-45 mph wide open.
On a long four-lane road with a gentle downgrade, where 50cc would take me to 42 mph, I could now reach 47 mph.
Going UPHILL, where 50cc would struggle along at 29 mph, I now sail up the gradient at 42 mph.
Put another way, I can now go as fast UPHILL as I could previously go DOWNHILL on the same road, with a significantly increased speed downhill and on level ground.
I am completely satisfied with the results of this BBK, and with the transaction from eBay seller scrappydogscooters.com.
In the ad for this particular kit, he was very upfront about the wrist pin being slightly too long (hence the very favorable price). Addressing the issue turned out to be very easy, took maybe 5 minutes to make it fit properly.
He also shipped my order very quickly, I placed my order on Friday, and received the box of parts on Monday. All the parts appeared to be very high quality, at least equal to those which I removed.
And the results are everything I could have hoped for. I'm still running stock jets in the carb (31 pilot and 88 main), and have changed out the variator rollers (originally 6.7 grams, now 5.0 grams).
I will probably experiment with the main jet, and possibly the rollers again, to see if I can break the magic 50 mph barrier.
If so, fantastic, if not, I'm still very happy.
