Motorized Bicycle Crank Balancing Made Easy! (CHEAT SHEET WEIGHTS)
Vložit
- čas přidán 5. 07. 2024
- Seems many want to make a balanced crank! Sure you see most people Just drill 3 holes in one and call it a day on CZcams! So how do you know what they show you is real or is it just a bunch of bs? Well it is kind of a little of both!
Typical crank is only balanced 60 - 70% Most 66/80cc kits are 65% or lower!
For an example Stihl chain saws will have a very well made crank with balance factor of about 75% to 80%. Or you can by the Walmart special chain saw which has one of 65% normally in that area! Bare bones min required to run. buy making the balance factor 70+% you increase bearing life! Reduce vibration! Increase piston and ring life from lack of deflection as a result! smooth running beast of a engine!
I had many questions of how in the hell did I make that crank and how I get the number to balance one! So here you go! a detailed video on what you need to know and do to balance a crank! How much to drill! and how much weight is removed as a result!
If your building a Minarelli, Ms380, Ms460 Ms660 a balanced crank is a must of your case bearings will be dust in a short time frame!
#Bikelife
#Ms660
#Ms460
#Ms380
#Minarelli - Auta a dopravní prostředky
Was flying all the sudden bang threw the rod right out of the case hit me in my chin then it shot down and cracked my gooseneck instant left turn right into a parked car.
i can tell yeah why! lolz bearings are only rated for 6500rpm. after that outer race will turn to dust chew up everything! Even bigger higher end ones only rated 8000rpm roughly before the go complete blown status. they will works sure! higher oil mix is what you need and you need to tune carb right for it so you don't foul out plugs! I tell everyone when i ride my bikes rune 32:1 no one gets that saves bearings no matter what oil is you use! but bearings can only handle 6500 rpms in short durations of about 3 minutes. then they expand cause friction. sure that is very tinny! when you talk about bearing! .02mm is huge in destruction after few minutes! don't get me wrong they will not blow right away takes time. cause each time they expany race gets little bit loser and then that is why they fail after repeat expansion!
Is there anything new for the big end crank bearing? I keep blowing those up my cranks are 49% balanced on Castor I’m turning12.400 RPMs
@thelonerider8389 ceramics are nice. Or you can buy a cobalt bearing bunch of rollers that sit in two half shells. Real biznitch to assemble 😂
I am fixing to do my first ms460 build soon, and all your hard work and dedication to this hobby/craftsmanship has allowed me to better understand the physics of having a great running engine! Had an issue with my Phantom 85 V3 piston rings melting into the cylinder wall and now I'm upgrading! Thanks bro!
Thank you for teaching and sharing your knowledge everyone else and the future generations
Thanks for watching 😉🛠
I can confirm this works. I used this exact formula, and it's like night and day. I still feel some minor vibration in the pedals, but hardly anything in the grips. This'll be my go-to on any CG crank from now on
oh yeah it's night and and day difference! for example first minarelli id did few years back normal crank like most use. Second build was balanced. couldn't even feel the motor running at 10k rpm. this last saw build i balanced it then had it computer spin balanced after like you do a new tire. it is amazing how much of a change super balanced crank is!
No video 🤔
@@JamesPiccone No video? Of what lolz? Lost! balancing crank? I must have like 10videos by now in all builds rebuilds done! lol
@@BuildBreakFix I was referring to the original commenter, respectfully not you dude.
@@JamesPiccone 🤣👍
man way more work then ill ever want to do lol . but you know your stuff buddy . hey just goes to show if i dint like ya i would not even watch cause i really dont care about all the motor work . but you knew that . i do enjoy watching you explain things would rather watch you ride but i think i would still want you to talk so its more of a hang out with ya for ten or twenty minutes and see what your up to kind of thing . take care buddy ride safe .
Yeah but these bigger build people want to make. This is a key step in the build process. You get this part right your destiny is success 😉
@@BuildBreakFix i understand brother i get that . tbh i dont understand it myself but i know there are others who like the build part . and thats cool . you do your thing man i enjoy watching ether way . dont make your videos for me brother do them for you . as you can see i still watch them no matter what you do lol . take care my friend
Thanks!!
༼ つ ◕_◕ ༽つ Your Welcome !
Was it for a 80cc cuz i'm confused now gonna have to get a scale...
Where in the world can you find the crankshaft that the Phantom uses ,the 12mm rist pin rod,,that's what I'm looking for for saw builds ,,so you don't have to bushing down to the 10mm pin, ,I have been m buying those cdhpower 110cc bottom ends just to get the Cracks out of them 115.00 dollars
The crank your looking for is called a zmn100. They are found in the ld100 kits and newer phantoms. also in the XY100 kits. They are called the 110cc Crank sets! Not sure about this amazon item as to I have not bought it myself! but a quick search shows a 110cc kit with ZMN100 in title! double check with this seller before buying! never know some post stupid info in titles! But they show exactly what one looks like in all photos and what listed should be in it!
www.amazon.com/DONSP1986-Assembly-Bicycle-pk80-66cc-Motorized/dp/B0822JG85C/?_encoding=UTF8&pd_rd_w=UhuZ5&content-id=amzn1.sym.bbb6bbd8-d236-47cb-b42f-734cb0cacc1f&pf_rd_p=bbb6bbd8-d236-47cb-b42f-734cb0cacc1f&pf_rd_r=DGCYPMTKND9E5B0957YN&pd_rd_wg=S30qd&pd_rd_r=d7e47f05-a2a5-46b9-8e8b-1e39a0d74ec9&ref_=pd_gw_ci_mcx_mi
Dam bro I can't tell you how much I love and enjoy your videos this one like all your videos are very much appreciated and understood. I hope you have the time to answer my other comment about building a MS 460 FROM TOP TO BOTTOM for me and how much it would be . I do understand it's not easy and going to be cheap. Your builds really impress the hell out of me and I'm sure others I've built Chevy V8 MOTORS for a street car back in my 20s now I'm 55 years young and really want to dive deep into this hobby thanks again bud.
Hey, Yes I am going to be selling these shortly! I actually am going to toss up a video of one selling shortly completed. For the last few months I let 5 delivery guys run around on 5 of these builds! Trying to make a rock solid kit that is not insane to buy and is reliable to run. The biggest issue I'm having is shipping on bottom halves. Either it cost so much it's crazy, or they wont ship to the usa at all cause everything so damn back logged still. Last few I bought came from India... to Brazil to Canada... Then to NY where they sat for 7 weeks in USA customs... to be shipped out to my house 2 weeks after that. It is crazy madness right now with shipping the way diesel is now! I actually have 10 complete engines sitting here. There all going to go up on the webpage once it's done shortly! Still trying set all that madness up to. lots stuff still going on but getting closer!
@@BuildBreakFix
Thanks for your reply and I understand. All this bull with shipping and whatever else is causing the backup. I would like one of those you have already and would hate to miss out ,but if it's meant to be it will happen I have time . My build isn't going to happen overnight for sure cause I want a solid foundation to put a power house like your engines into lol but yea keep it up and I will keep my eye out for your info on this situation. Thanks again for your time bud.
Does drilling holes in your crank affect crankcase volume & Isn't that the opposite of stuffing your crank?
You know I asked that to! I asked the guy that computer balanced my ms460crank . All he did was cranks and dirt bike rebuilds for super cross like last 45 years lol! He said honestly does not matter when you start putting huge ass pistons in the smaller cases cause you already increased the volume in and out a ridiculous amount from what that case was rated for to start with. so I guess in terms of sticking a piston 52 mm in that case meant for 47 already kind of makes up for that in way 2 stroke functions. holes in crank are not enough to make huge change with larger volume of air/fuel mix now being compressed in a 477 mm piston sized crank case. I guess it's a give and take cause if it's not balanced either larger ones bearing turn to dust really fast! He is one those old time guys that was on race seen years then now builds the engines newer generations run kind of guy.
@@BuildBreakFix I remember seeing videos of dudes filling the holes with JB weld, lol. I'm very curious to see how much more smoother balancing your crank feels to ride.I just personally hate splitting jugs if I don't have to. I have only had vibration issues in the past but it was only the mounting and chain alignment. I also don't run tire slime anymore because the added weight was causing wheel issues past 40 miles an hour.
@@JamesPiccone It's actually like vibration free! Super smooth! IF you spin that thing up to like 9k rpm you feel zero shuttering it's amazing! I just did my 100cc one last night as well! Thing feels super smooth to! Didn't have choice on that one cause crank rod actually cracked in it... yeah never seen that before either! So figured why not lol!
Thanks for sharing! Do you measure the hole from the tip of the drillbit or only whole 12mm diameter counts? I am asking because I tried to calculate it on several online steel calculators and all say that single hole 12mm diameter 12mm deep is 10g .
normal drill tip is 135 degrees is what it is based on.
Kdy z toho bude video? :D
@@BuildBreakFix so, do you measure from the tip, or the 12mm part?
@breezetix typical drill bit is angled at 118 degrees. It would be measured from the tip. Provide it's tip is not custom ground
@@BuildBreakFix ok
Hey just wondering didn't you order a piagio bullet case engine a while back have you received it yet or did you back out or something
No I have one! Didn't buy all the parts. Just a bottom cnc case, jug,piston,head. Missing lots other stuff to be complete. Oh and I got a ktm50 shaft adaptor I think it was called and cnc side covers.
Ha did I tell you about my Gemini hub? Lol. I think you messaged me about yours came asap. Was like wtf.. don't even know how I did it but I bought the wide one they are starting to produce soon . That is why it's taking so long! So... guess this means I'm making occ chopper lol
@@BuildBreakFix oh I can't wait to see your piagio bill give me a surprise how much torque those things have and Orange county choppers cool but maybe look into something more bigger and comfortable
@@mozezcen-valley7555 well type of hub I purchased was that new fat tire hub there making. I must of added it as I was shopping instead of mainstream one. Reason I say that. I have one that is mint condition with no point but looking nice
Hello sir , it appears when I took appart my bt 100 that my crank has 10mm holes pre drilled instead of 12 mm , do we have any data for 10mm holes like the ones you have on 12:39 ? , awesome guide btw
According to my calculations with a pk80 rod and my (piston,rings,clips,small bearing,wrist pin) weighing 127 grams , so In total 254 grams need to be taken out (form a crank with no holes) , I suppose I should modify the crank to have 2x5 straight through holes (10 x 25g=250g) leaving me with 4 grams that theoriticaly I could take out too (but wont for maybe windowing my piston later) . Does that look reasonable ? (bt 100 came with a 50 mm piston and dual rings stock) just a bit paranoid
I never owned a bt100 or seen one actually in person! So couldn't tell yeah. I think there hard to buy in the states
Whats the distance between the holes being drilled? I would imagine too close/too far apart from the factory holes would effect the efficiency of the balance.
115mm
Sorry wrong question answered lol. 20 mm center to center crank drill holes
Hi bro. How do i know the spacing and distance to the exact point that i’m gonna drill ? And you have any idea of the total mass of Phantom 85 V3 ( rods/ bearings/ wrist pins / clips, etc ) so I don’t have to remove them out ? And start drilling straight out ? Much appreciated if you can answer
Sadly phantom was made so badly. Nothing on them ever is the same. So many versions and 3 different pistons made.
@@BuildBreakFix so looks like i have to tear then apart and follow up with your method lol
How do i split the crank halves apart
Gear puller! Watch that czcams.com/video/opt9-Zsa3y8/video.html
Would the 3 12mm holes work on the Phantom 85? Everyone is claiming lots of vibration on the second gen. I got one a couple months back but haven’t started it yet, tore it down to clean it out and just about shit when I saw all the debris in it from the factory. Just wondering if I should rip it back apart and drill the holes??? Thanks and keep up the builds!!!
Vibration is caused by the piston pin bushing sadly. Gen 3 has bearing like 2 strokes need. Whole phantom is super bad copy of ms380. My ms460 I just built. I made the wrist pin adaptor. For it.
czcams.com/video/xPKRLpkpM_g/video.html
Holy shit thanks for replying so fast! Been getting the parts together to follow along on your stihl build. Time is the main factor for me guess I was just wondering what your thought was on the crank. I’ll take care of the wrist pin issue too before I crank it up. Ordered the damn thing before I found your channel or I wouldn’t have gotten it. But I have it now so going to do what I can to try and keep from blowing it up. Already cerakoted piston top and got most of your super clutch done 👍
@@setherickson7376 going to be doing second ms460 with normal tools in a bit. May be opening store just selling premade parts for them soon!
@@BuildBreakFix Somebody should let the sawdust guy know
What’s your thought about pistons that weigh less than stock? The piston I want to use is 11 grams less than stock (60 vs 71). Think I would still need to drill out balance holes?
Stock what though? There are 11 stock pistons lol windowed or non. A or B 50/80cc type, Yd100, kx110 crank. Lots of factors to consider. If I knew what stock means in terms of what you have I probably could give a good ball park figure. Rod stamp, crank halve type, piston w or w/o window. Then diameter and height of new one.
@@BuildBreakFix lol man I was hoping to not get all technical and all but…
So it’s a fm80 rod solid pin crank (17mm web crank) that’s gonna be using a ms360 piston. I just compared the piston weight to some random 47mm high hole piston
hey , i just tried to balance my crank and its worse at low and mid rpm but vibrate less at high rpm and feels smooth, any ideas?
Did you do it yourself?
@@blakake yea nevermind it works mint
sometimes if you don't true up axles correctly! they will wobbles at first lol! till they align after a few rips down road provided there very close. this why im now lazy take them to a bike shop have then toss it in a machine for 10$ roll the crank halves true and hand it back to me lol! done few by hand you can do it! just takes a lot of aggravating time to do it lol! close the engine running will self align them as it breaks in after few runs! (edit) even with bike shop doing that still get vibrations first few rides till breaks in after few rides) part of why you break in an engine at 50% less throttle! most don't realize this is part of it!
@@BuildBreakFix yea i noticed this , also the carb is a thing lol!! When i ran the pwk kinda lean it wouldn’t vibrate but the nt speed it does a bit
I have a crazy issue. Been working on a 50cc bike engine. It's been a disaster from the word go. What is the normal width of a 50cc crank From outside of bearing to outside of bearing? Mine measures 2.165". The problem being that the inside of the crankcase is only 2" give or take a few thousandths. There's no way in hell this will work. It had two thick gaskets on it when I got it and was a witch to turn, duh. So which part is wrong so I know which one to replace?
Well normally crank is actually (50mm) roughly 1.98" wide. Crank case is (52mm wide). 2.047" either you didn't fully pressing bearings into the case. Or the cranks rod pin is not fully pressed into place. It should be flush with outside of crank webs surface where it goes into them. But every crank 50cc/80cc/100cc/yd100/bt100 is 48-50mm to where each bearing sits on it. Never over that! Cases are always 52-54mm 90% time you actually have to add spacers cause of it being to big! So check pin and make sure the bearings are fully pressed in be suprised how a nearly unseeable movement changes stuff going together with cranks.
@@BuildBreakFix I'm a hands-on mechanical engineer. Been building engines over 40 yrs. There's almost no technical info on these engines. I I know how to do math thank you and I surely know how to map bearing placement on a crankshaft. The pin is pressed flush on the crank on both sides and the bearing offset on both sides of the crank is about .050. The answer here is that the crank is the problem and the case is fine, so I'll order a new one. Once I finish getting my shop set up this will be food for the lathe. I'll deal with it later. Thank you for your reply.
@@riverseden5051 lol why ask then.... there all 50mm. Typical engineer response then cause that was my job 35 years. Making impractical designs on napkins work in reality
🤣👍 remember that next time you take airplane flight lol. All 874 of these engines i rebuilt or custom made for people have been 50mm even higher end billet cranks are spaced 50mm lol. Not saying you cant do math.. Then the cranks pin clearly not pushed in correctly If its wider then that. Cases are always 52 to 54mm apart.... even cnc billet cases. Even if pins not seated 1mm fully they still fit. So makes no sense! All I'm saying......
@@BuildBreakFix I know it doesn't make sense. That's why I asked for the dimensions. Trust me, the crank pin is pressed all the way flush on both sides. Now I know what the dimensions are supposed to be. The crank is the problem. Mystery solved. I have a case that will fit 51mm bearing to bearing and a crankshaft that is 55mm bearing to bearing. Square peg round hole scenario. I have another brand new engine to disassemble and go through, so I'll just go from here. I appreciate the information.
@@BuildBreakFix I simply asked a solid question in order to solve a problem. I appreciate your reply. Didn't ask for your opinion.
which rod did you weigh YD100?
All of them! Af80 85grams / zl40mm is 88grams / yd100 is 93 grams / mzn100 is 103 grams (new phantom rod)
So you just ballpark the location of the holes? You don't do any real balancing to find out precisely how kuch to remove or where to drill?
No no. You need to have all the holes center point be the same distances. Find the center point between the two stock holes. What ever that comes to center of stock hole to center of new hole. Copy that on other side of each stock hole for 4th 5th holes. Most take a campus put a pin against wall of a stock hole draw a line tile the half circle lines meat perfectly from each stock hole. Then make one on other side of each stock hole find that center point and drill
Soo... Drilling 3 holes 12mm deep should net you 60gram of metal ? How did you figured that out? did you kept the metal burrs and weight them? 🤣
Yes lol. When I made the 5 minarelli build and 3 md660 builds and methonal yd100 only way I could balance them 🙂👍 they where identical every time!
@@BuildBreakFix wow that incredible you had to been super diligent and mindful not to lose any that burrs. I would have to guess the first crank must all been trial and error and second one from there on was all just fine tuning.
@@dreadknot2238 actually an older builder told me the info that actually passed away from covid few months ago. These cranks are in other China engines as well! They repurpose these in many of the 1/4 scale rc engines as well. So I drilled oh my maybe 30 rc cranks now. I did 11 motorized bicycle cranks well 12 now since just rebuilt 100cc iron sleeve lol
soooper freakin creepy introduction doood
Yes lol! Creepy lady talking? Yeah was not fond of it either! Think was last video with it lolz
Great video. But window pistons would all be different in weight, also there is two different thickness in the crank weights, the pk80 have a thicker crank weight width than some other ones. If you included the thickness on your crank weights i think that would have been the 1% of info you missed.
Thickness means nothing. You never drill completely through you drill 10mm deep into steel any thickness crank web still weighs same if hole is drilled as deep... piston whit window or no window. Your weighing it and all parts anyhow. Not really a factor that matters! Even if you cut a window after you used normal piston and did it correctly only 4% weight change it would still be 65-70% balanced for 2 stroke is near perfect anyhow
@@BuildBreakFix so the thickness of the crank weights wont change the weight of the crank thus making the balance factor different?
@@jaycee2366 why would it. your measuring the piston, bearing, pins and clips con rod and it's crank web bearing. You find balance factor weight of the crank it's self. then take away difference from the crank. If it was 5 inchs wide still only removing off set weight from it no matter how heavy the crank is.
Think of it this way! If you had a 5 inch thick metal disc or a 1 inch thick metal disc! You add a 5 pound bolt in each randomly some place! you need to remove 5 pounds of weigh from both discs to make up that difference regardless of how big the disc is! After they would be perfectly balanced again cause you removed 5 pounds of material to offset the weight of the bolt!. Hope that explains it!
@@BuildBreakFix sounds good. For some reason i thought the crank weights would have something to do with balancing. But the way you explained i guess that makes sense. Good too know.
@@jaycee2366 if you want to get a super detailed view of how to balance one! Like process. "twostrokesuffings" has a video in great detail whole process start to finish some place!
I need your help, and I believe you're the only one smart enough to help me.
My balancing stand is perfect and level. When I add hung weight, the crank simply wants to drop down, there is no "you can put it in any position with hung weight attached and it will stay perfectly still" I believe this has to do with the weight of the conrod being heavier, hence why the crank moves less before the hung weight, and gets worse as more weight is put on. In a perfect world, the crank should stay still once I add X amount of grams of hung weight.
How're you supposed to navigate around this? There is no way to get the balance factor from it then? Before someone decides to jump in the comments and say "that means its balanced then" I can ensure that my crank didn't receive critical QC care in the sweatshop.
List the parts. What kind of piston, crank type, con rod stamp. List those can probably get you close. So when you roll it. You actually need to have a piston all that attached to it all. Rings bearings and so forth. (Getting it to perfectly) standing still is ideal. But not necessarily a deal breaker. If it doesn't. 2 strokes can run perfectly fine up to 6500rpmd 65% balanced. After that you have to balance it about 5% more for every 1000 rpms. Anything past 8,000 is past the crank bearings ratings anyhow. So at 75% balance you technically would be able to run one perfectly fine without failure at 8000rpm. Another thing is to make sure it's on the shaft. When you balance a crank. So many do it on bearings and give false results as well.
I dont know why , but I trust this guy more then my favourite 2 stroke stuffing, just because he weighted the whole conrod not just the half ???
Should i do this my crank is 100% nor running true, my fuel stoped when i was going like 35mph and my motor bited, because it was not properly greasing, but it almost imediatelly unstuck, but my conrod is now very wobly ( even side to side) and its vibrating as hell.
Honestly He gave you a very simple way to do it! It is close enough to get way past the 65% mark into upper 70% So his method is really not that bad if yours is already assembled! Most don't realize you only need balance factor of 65% to have a semi decent runner! 70% up really smooth! Only way get past 75% actually weigh each part one at a time! I scratch build many cranks so figured I just give you all actually weight and cheat sheet! when you go try build your project! But yes his method is very solid! It gets you well into the smooth running ranges! But all honestly! if the crank no longer true after a hard stop! Either a webs shaft bent or the crank pin is bent. either way if you buy a new crank it will save you lots of aggregation for 20$ lol yeah normally man when engine hard stops and vibrates normally bent not fixable!