I like what you're doing. In the 70s my father started a drive shaft balancing business so that he would have a balancer to balance his V8 racing engines. At that time I started getting addressed in Two Strokes. All kinds of different ones Kawasaki triples mostly. One of the things I learned is removing all the metal from the crank adds volume to your crankcase. Usually I would remove metal from the light side then add Mallory and then weld a cap on leaving no holes in the crank. Also well drilling holes always made a cardboard template to collect all the chips to weigh them. Always helped with the calculations of weight removal. I know it doesn't sound like much but crankcase volume is very important. Also in certain circumstances when removing weight from the heavy side we would remove more weight than necessary than TIG or mig weld caps over the holes then machine them down flush. Or just a hand grinder. Just some food for thought. I like the video.
your absolutely correct this add volume , i did this DIY Crank for the average builder , most people don't have the resources to do what your saying , in saying that the average engine builder can achieve a balanced crank
i assure you the con rod weighs more than 30 something grams. it's more like 80 grams. Why not balance with piston connected to rod. why would we not strive for as close to a 100% balance as we can get? 60% seems low to me
Darcy, You are the MAN bro you will be my builder when I can afford my motor thanks for perfecting your art . I feel safe by having you build my power plant ! Keep up the good work and video's of your builds I love your designs of your bikes .
I hate your marker dude. Felt like I was going to vomit while having a seizure listening to that. Worse than nails on a chalkboard. 😂 Great video though. I learned a lot from this.
Drilling a balance hole directly beside or inline with the crankpin is a bad idea for obvious reasons. That's why the 2 original factory drilled holes are spaced either side of the centreline of the crankpin. Better to add weight to the opposing side (ie. Drill a hole, thread it, then pour in lead)
I tried balancing my crank and it came out to 67% balance factor and it’s very smooth at low rpm’s but at high rpm’s it vibrates like crazy, never had a engine vibrate that much, checked engine mounts and everything and it’s all good, wonder why it’s doing this.
Thank you LA Hover , hopefully this video will help people understand what it take to make a balanced crank instead of just drilling holes like most do
So, I noticed if the scale is lifted to make the con rod level it changes the weight vs just leaving the scale on the table and being close to level. Which way is accurate? The conrod needs to be perfectly level in order to get the proper weight, doesn't it?
@dlhperformance7169 I ultimately decided to lift the scale using a deck of cards to make the con rod level. Without lifting the scale I was getting around 38.4g, with lifting the scale it says 40g. Interesting find to say the least. Thanks for sharing your skills man. Your information is priceless.
I appreciate the video but I'm confused on two things. What size bit did you use to drill the holes? In the beginning of the video you measurd the thickness of the crank but I don't understand why considering you used the same measurement of the distance between both stock holes, and then usedtbe same distance for the other two holes
the drill holes size doesn't matter , its the weight of piston and everything on the conrod , you need to do the calculation and remove the material as needed by drilling holes , the calculation will help you get the desired percentage over rotational mass
That's nice but i still don't get it,i mean,why do that; ---what happens if you don't balance it? ---what do you do with the balance factor? ---if you have a GY6 150cc and you go for the big bore 171cc, what happens with the balance? will it vibrate alot?
1, vibration and rpm range is why your balancing this crank ( factory cranks from these china doll engines are usually not trued or balanced for your piston } its a cheap built crank ! 2, your aiming to get a 50 - 60 percent balance factor , lots of variables in this. one is piston drag , friction causing piston to be seemingly be at a higher weight at 12k rpm 3, a GY6 crank is a engineered , higher manufacturing standards , milled perfect, and yes a lot of cranks guys change the balance factor for racing
Brother when i balance the magnet side of a crank the clutch side goes unbalance then when i do balance of the clutch side then magnet side goes unbalance what’s the reason behind this?? Can you explain
