Joined Jul 2001
3K Posts | 1+
El Sobrante, Ca. 94803
I received the following from a friend and believe many shall find the information useful:
I used a balance factor of 67% what is close to your 70%,on my JBS kit with Lineaweaver valves + X2 cam.
I have on the moment 2 problems;
1) engine won't revs ------ problem is on the needle is too rich will be solved.
Indeed, I understand the rich condition given the large displacement.
2) but the second problem is the balance factor,I have now 67% when I accelerated the engine to 5000 RPM it all goes well,but higher than that the VIBS are higher but do able. When I decelerated it is heavy on the hand grips,a lot Vibrations.
Yes, unfortunately with very large singles it is difficult to reduce strong vibration @ some rpm. Changing the balance factor tends to move the strongest vibration around the rpm scale. Unfortunately most often best results are obtained via trial and error.
Now what Can I do on my balance factor higher or lower????
Since the vibration is strongest without a load I am inclined to believe you can change the motorcycles "Natural Frequency" to offset the negative results of the strong engine vibration.
What is the reason it vibrates more on deceleration and with acc it is do able ,do you have an explanation??
No load allows the entire motorcycle to vibrate. When the motorcycles natural frequency matches that of the engine vibration is multiplied. like a shock without damping.
Change the entire motorcycles natural frequency:
Example:
Use weighted handle-bars, bar end weights, bar inserts, stronger foot-rest springs, stronger exhaust springs, thicker exhaust tubing, etc. Anything to change the natural frequency of the motorcycle as a whole.
Hope this helps.
Sincerely,
Dale
Ps when I will test on the dyno it is possible that I buy a X 1 cam to have max
Yes, The big engine should do well with the X1.
I used a balance factor of 67% what is close to your 70%,on my JBS kit with Lineaweaver valves + X2 cam.
I have on the moment 2 problems;
1) engine won't revs ------ problem is on the needle is too rich will be solved.
Indeed, I understand the rich condition given the large displacement.
2) but the second problem is the balance factor,I have now 67% when I accelerated the engine to 5000 RPM it all goes well,but higher than that the VIBS are higher but do able. When I decelerated it is heavy on the hand grips,a lot Vibrations.
Yes, unfortunately with very large singles it is difficult to reduce strong vibration @ some rpm. Changing the balance factor tends to move the strongest vibration around the rpm scale. Unfortunately most often best results are obtained via trial and error.
Now what Can I do on my balance factor higher or lower????
Since the vibration is strongest without a load I am inclined to believe you can change the motorcycles "Natural Frequency" to offset the negative results of the strong engine vibration.
What is the reason it vibrates more on deceleration and with acc it is do able ,do you have an explanation??
No load allows the entire motorcycle to vibrate. When the motorcycles natural frequency matches that of the engine vibration is multiplied. like a shock without damping.
Change the entire motorcycles natural frequency:
Example:
Use weighted handle-bars, bar end weights, bar inserts, stronger foot-rest springs, stronger exhaust springs, thicker exhaust tubing, etc. Anything to change the natural frequency of the motorcycle as a whole.
Hope this helps.
Sincerely,
Dale
Ps when I will test on the dyno it is possible that I buy a X 1 cam to have max
Yes, The big engine should do well with the X1.
