tom-fishing
Member
Rode to the store and post office, then beat the rain back home. 
What did you do to your motorized bike today?
- Thread starter MotorBicycleRacing
- Start date
darwin
Well-Known Member
- Local time
- 10:30 PM
- Joined
- May 26, 2008
- Messages
- 8,014
Rode today 30 miles, local news said 59deg and I wore a tshirt and a hoodie. I was freezing. It was fun but it wasburrrrrrrrrr.............. Was thinking about all that I have involving MABs. COME TO THE CONCLUSION only a honda50 with chain/fd staton will make me content. My day............yours?
D
Deleted member 12676
Guest
the topic is "what did you DO to your motorized bike today?"
not what did you think about doing, or how did your day go today?
not what did you think about doing, or how did your day go today?
5-7HEAVEN
Well-Known Member
I commuted to work again, 12-mile round trip. Engine running fine, no breakdowns lately. Chain jumping and chain breaking no longer a problem. For years, I've also had brutal shift changes even while slow shifting. The bike wants to slide you off the seat on the first shift, even tho starting off in Second gear (38.18:1). The gears I used were Second, Fourth (28.64:1) and Seventh (17.73:1). Now I shift from Second to Fifth (24.55:1) to Seventh. No more sliding off the seat, nice gear spread and smooth shifting!
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Deleted member 12676
Guest
I tested my transfer port modification and it did have better low rpm power. Next I will put another piston in which doesnt have the transfer and exhaust ramps and see how much more low end power I can get with lessened port open durations. These 48cc engines need all the help they can get!
Fabian
Well-Known Member
I'm really keen to see the results of this experiment!
D
Deleted member 12676
Guest
Fabian, as you probably know the 48cc is so weak that its hard to notice any change that is not more than 10%. When I lived at high altitude I had the advantage of long slightly inclined streets that I could use to gauge results by top speed. Now I live in a coastal town that is purely flat which makes it hard.
Anyway lowering the exhaust/transfer port durations resulted in just enough of grunt-from-a-stop to make this engine liveable in the city. Otherwise, throw it in the trash and upgrade to a 55cc or 60cc. I lowered the durations by replacing the piston with exhaust and transfer ramps to one without. That probably lowered my peak speed but I couldn't tell just by riding it. I had taken off the speedometer previously. This engine is so weak from a stop that improving it in that area should be the top priority. This engine has an extended intake track, 14mm Dellorto carb with extra holes in the fuel column, two types of modifications to the transfers for fully correcting the direction of intake charge, stuffed crankcase (which is a mistake with this small engine since it causes more of an emphasis on top rpm power), standard exhaust pipe with a 5" longer header welded in, Jaguar CDI, and uses synthetic oil. The final intake port duration is the ideal 120 degrees. Main jet in the Dellorto is drilled to .63mm.
Port durations were changed from exh/trans/intake 143/108/124 to 139/100/120.
Anyway lowering the exhaust/transfer port durations resulted in just enough of grunt-from-a-stop to make this engine liveable in the city. Otherwise, throw it in the trash and upgrade to a 55cc or 60cc. I lowered the durations by replacing the piston with exhaust and transfer ramps to one without. That probably lowered my peak speed but I couldn't tell just by riding it. I had taken off the speedometer previously. This engine is so weak from a stop that improving it in that area should be the top priority. This engine has an extended intake track, 14mm Dellorto carb with extra holes in the fuel column, two types of modifications to the transfers for fully correcting the direction of intake charge, stuffed crankcase (which is a mistake with this small engine since it causes more of an emphasis on top rpm power), standard exhaust pipe with a 5" longer header welded in, Jaguar CDI, and uses synthetic oil. The final intake port duration is the ideal 120 degrees. Main jet in the Dellorto is drilled to .63mm.
Port durations were changed from exh/trans/intake 143/108/124 to 139/100/120.
5-7HEAVEN
Well-Known Member
It was another great ride to work. However, the pullstring jammed as I prepared to leave my workplace. Removing the pullstart to repair it, you can imagine what happened.....BOING! The clockspring popped out. Reassembling the pullstart was an exercise in futility for me. Luckily, my family happened to be a few blocks away. I secured my MB onto the bikerack and went home with them. Fortunately, I have a spare 47R in storage. The next morning, I visited my storage locker, retrieved the pullstart, then my wife dropped me off @ work. At day's end, I installed the spare pullstart and enjoyed another great ride home.
D
Deleted member 12676
Guest
So ****ing hang me! I subscribed to a thread that's supposed to be about things people DO to their rides, not what everyday stuff they do that has little to do with bikes. Darwin, please feel free to start a thread entitled "dumass stupid stuff I did today with no relevance to motorized bike maintenance or upgrades". Be my guest. I don't want to waste my time having to read that someone rode his bike to the store. That's all. I think you like that though.
