Hello Question The main gold here if I understand. If I do what you saying and put the piston on the rod. It should balance out just like you doing and the crank will stay at any spot I stop it at. If not I need to remove some metal by drilling. Thanks Enjoyed your post
I am missing something here ! As always a piston to be changed will be bigger , heavier but never smaller [big bore]. Hence the issue of stock crank counter weighs being light, changing the balance factor for said piston . Drilling holes will only work if filled with mallory metal or spend extra for a slimmer stronger piston ?
I could could use a bit of help with a scooter engine build, I have one engine now with a big bore, 39mm to a 50mm, and have another I'm planning on going with a 52.4mm bore, the 50mm has a vibration that comes in from 7k to about 8600, then eases off almost completely, I have seen 10,300 but i try to keep it under 9-9500,the Pistons for the next build , I have ground all the rough lines I'm not sure I think one may be forged, or billet, it sure cost enough, but I tried to lighten it as much as I could without weakening it, and took about 1.3mm off the skirt, because of weight, and I may get a stroker crank, I was hoping to get the piston weight closer to the stock weight, it's not going to be that close, a piston 11mm larger is going to weigh more no matter what! But I want to balance the next engine, and maybe the one I'm using now, when I swap to the high compression piston, and big valve head, it would probably work ok as is, but definitely not great for the bearings! Any advice?
Michael Forrest has a spreadsheet balance calculator that is interesting in that you can plot the forces at a certain rpm. If you did that on your engine at the vibration rpm, you could find out how far out the forces where. It is always a compromise over the rpm range. With calculating it out over a realistic rpm range a reasonable balance can be found.
A four stroke engine is balanced dynamically with an externally fitted damper along with the internal balance factor.what that factor is would depend on the builder's preferences and the reciprocating mass.
So how do you work out balance factor and know where and how much to drill? You may have been better off doing some diagrams on whiteboard in background.
The balance factor is the percentage of reciprocating mass that statically balances vs the actual reciprocating mass.How much you drill is up to you and what factor you want to achieve.
Hello
Question
The main gold here if I understand.
If I do what you saying and put the piston on the rod. It should balance out just like you doing and the crank will stay at any spot I stop it at.
If not I need to remove some metal by drilling.
Thanks Enjoyed your post
I like your shop!
Good video, this will work if u can't afford a shop
Great explanation. Tnx.
I calculate those figures as 58% balance factor. Add the Conrod weight to the hung weight devided by total reciprocating weight.
I am missing something here ! As always a piston to be changed will be bigger , heavier but never smaller [big bore]. Hence the issue of stock crank counter weighs being light, changing the balance factor for said piston . Drilling holes will only work if filled with mallory metal or spend extra for a slimmer stronger piston ?
Thanks for the breakdown and the information 🎚🇺🇸⚙️🚲⚙️💥👍🏼💯👊🏼
I could could use a bit of help with a scooter engine build, I have one engine now with a big bore, 39mm to a 50mm, and have another I'm planning on going with a 52.4mm bore, the 50mm has a vibration that comes in from 7k to about 8600, then eases off almost completely, I have seen 10,300 but i try to keep it under 9-9500,the Pistons for the next build , I have ground all the rough lines I'm not sure I think one may be forged, or billet, it sure cost enough, but I tried to lighten it as much as I could without weakening it, and took about 1.3mm off the skirt, because of weight, and I may get a stroker crank, I was hoping to get the piston weight closer to the stock weight, it's not going to be that close, a piston 11mm larger is going to weigh more no matter what! But I want to balance the next engine, and maybe the one I'm using now, when I swap to the high compression piston, and big valve head, it would probably work ok as is, but definitely not great for the bearings! Any advice?
Michael Forrest has a spreadsheet balance calculator that is interesting in that you can plot the forces at a certain rpm. If you did that on your engine at the vibration rpm, you could find out how far out the forces where. It is always a compromise over the rpm range. With calculating it out over a realistic rpm range a reasonable balance can be found.
Mantabs sir...👍
Sean is there a chart of ballance factors and what rpms they suit
sir, please answer, what percentage of balance factors is best for a 4-stroke engine that works in the range of 1000 to 10000 RPM ?
Thank you
A four stroke engine is balanced dynamically with an externally fitted damper along with the internal balance factor.what that factor is would depend on the builder's preferences and the reciprocating mass.
@Eddie Hitler one cylinder vertical engine
Can I drill the hole anywhere in the crank, or does it have to be in a certain spot.?
The first hole or holes should be between the stock two,after that it's up to you and you're needs.
@@streetriders4405 awesome thank you.
wouldnt adding holes make you loose compression?
loose? I think you mean lose! DA
Also adds more crankcase volume..js
why would you lose compression from drilling holes in the crankshaft? lol...
So how do you work out balance factor and know where and how much to drill? You may have been better off doing some diagrams on whiteboard in background.
The balance factor is the percentage of reciprocating mass that statically balances vs the actual reciprocating mass.How much you drill is up to you and what factor you want to achieve.
This is not a good way to balance a crank , not trying to be rude.
What is a good way
@@markilleen4027 letting the government do it was his reply