danlandberg
Active Member
So you were able to open the link? I tried to open it after the post, and could not see the jump. So where is your trip taking you? (from where to where?) Be safe Mike!!......DanGerous
Top speed and rpm loss?
- Thread starter danlandberg
- Start date
MikeJ
Member
No, I did not open the link. But I remember some of Knievel's stunts and his injuries. I know the vibration syndrome well. Your advice has been noted.
Back to engines: I will try your setup in a trial local trip during the next few days. My planned long trip will cover altitudes between 5365 feet (Limon) and 6830 feet (Falcon). If my engine is going to melt down or seize, I want it to do so close to home of Colorado Springs, not destination of Limon, CO, the intersection of Hwy 24 and I-70. I will post some more after the trip (weather and physical condition permitting).
Back to engines: I will try your setup in a trial local trip during the next few days. My planned long trip will cover altitudes between 5365 feet (Limon) and 6830 feet (Falcon). If my engine is going to melt down or seize, I want it to do so close to home of Colorado Springs, not destination of Limon, CO, the intersection of Hwy 24 and I-70. I will post some more after the trip (weather and physical condition permitting).
MikeJ
Member
Went out for a run today after setting the tiny clip to the end of the carb needle and pouring in a batch of 20:1 oil mixture. The outside temperature was 90 degrees, where earlier runs were at 70 degrees or so. Did not feel any significant change. The only noticeable difference was that torque while climbing hills improved. At about 17 mph during a hill pull, the engine switches from its usual 4-stroking to 2-stroking until max rpm and the hill peak have been reached. Then it goes back to 4-stroking. Above 5600 rpm / 24 mph, severe engine vibrations set in, so I back off the throttle. The mechanical vibrations will be the limiting factor to continuous high engine rpm; I don't think this is influenced by fuel ratio or temperature or rider weight or fuel/air ratio or anything else. My rpm seemed to max out at 6000 rpm / 26 mph on the flat straight-aways using standard 44-tooth rear sprocket. (Of course, faster when going downhill).
To help torque, I loosened the screw holding the end of the muffler pipe, effectively lowering muffler internal back pressure because now exhaust gas can escape around the loose end piece. To keep the end piece from falling off, I use a low-tension steel spring from Ace Hardware to hold it in tension to the bike frame.
Spokes were all reasonably tight. The rear wheel instability was caused by low rear tire pressure (30 psi). After bringing it up to 55 psi, there was no more instability.
I may go back to 24:1 oil ratio. Other than this, I do not plan on making any more engine changes.
Another lesson learned: I am going to place duct tape over any loose shoelaces and loose pant legs. One shoe lace melted down in contact with the muffler, and one shoe lace got chewed up in the right-side crank sprocket.
Another 35 mile fun ride today! Total now is 233 miles.
Mike
To help torque, I loosened the screw holding the end of the muffler pipe, effectively lowering muffler internal back pressure because now exhaust gas can escape around the loose end piece. To keep the end piece from falling off, I use a low-tension steel spring from Ace Hardware to hold it in tension to the bike frame.
Spokes were all reasonably tight. The rear wheel instability was caused by low rear tire pressure (30 psi). After bringing it up to 55 psi, there was no more instability.
I may go back to 24:1 oil ratio. Other than this, I do not plan on making any more engine changes.
Another lesson learned: I am going to place duct tape over any loose shoelaces and loose pant legs. One shoe lace melted down in contact with the muffler, and one shoe lace got chewed up in the right-side crank sprocket.
Another 35 mile fun ride today! Total now is 233 miles.
Mike
give me vtec
Active Member
got ya...
MikeJ
Member
Now I understand better why performance improvement did not materialize. I did a word search on "lean". I read a lot of comments. It now seems that if air density is too thin (like a day of high temps at a location many thousands of feet above sea level (90 degrees in Colorado Springs)), just moving the tiny clip on the carb needle alone is not enough to sufficiently lean out fuel being atomized; hence, the continuous four-stroking. Many writers talk of filling and drilling main jets to smaller-than-factory sizes. I will let the experts do that. I expect that cooler temperatures or riding at lower altitudes (greater air density) will produce a better running engine. In the meantime, the bike starts well, runs well, and is best left as it is.
Off-topic: A motorized bike is an oddity in this town. I am getting inquiries about where to find info almost every time I ride.
MikeJ
Off-topic: A motorized bike is an oddity in this town. I am getting inquiries about where to find info almost every time I ride.
MikeJ
Hawaii_Ed
Member
Carb clip only changes the air/fuel mix at idle and partial throttle. Lowest is most rich, top (furthest away from the point) is full lean. WOT is jet only. Filling and drilling is to get it more lean, if you need to be more rich you can just drill it out, or replace with an aftermarket jet. Best indicator is spark plug color after a good WOT run. If it is light tan or white you are too lean.
I had the 4 stroke problem on my single speed beach cruiser, put a new engine on the shift kit bike and it does not do it at all.
Mike, you can also just take the whole end of the muffler off, drill a hole, or two or three in the pipe at the base, and put it back together.
I had the 4 stroke problem on my single speed beach cruiser, put a new engine on the shift kit bike and it does not do it at all.
Mike, you can also just take the whole end of the muffler off, drill a hole, or two or three in the pipe at the base, and put it back together.
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