Here is a post I made a while back:
Generally there are four weights on two axis, when the piston is at the top of its travel (TDC) the crank weight and counter balancer weights are at six o??????????????????clock and are working in tandem to offset the reciprocating weight of the piston assembly. When the piston is at the bottom of its travel (BDC) the weights are performing the same function however they are at twelve o??????????????????clock. This is called BDC and TDC inertia.
The other two are called ninety-degree inertia; this is the forward and rearward orientation for this specific engine. At the ninety-degree axis orientation the counter balancer, crankshaft due to they??????????????????re opposite directions of rotation offset each other. The counter balancer weight is calculated as the difference between the required counter weight for the TDC/BDT axis and the ninety-degree axis counterweight requirement. Note: no single cylinder engine can currently be perfectly balanced. Counter balancing gets it closest to the theoretical.
Dustin
Balanced Engine vs Balanced Crank
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DangerRanger
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- Joined: Wed Mar 10, 2021 10:41 pm
AHHa....but one key thing is missing, everyone who is not balancing the crank correctly and ridding the EXACT cause of the unbalanced conditon is only taking your money...you can balance them on any f-ing machine you got, but if you don't fix what is causing the problem...it will come right back. I have been involved inthree cranks balanced.....all of them checked fine, I took them to different shops and had them checked again to confirm Winky's findings....sure enough they were back out and hadn't even been run/or installed.....the ones he has done...checked twice with no problems. The new motor he is building should be the same, with the crank done correctly It was not a manufacturing or change problem....it is a process they missed while making the cranks, and someone has figured it out....Mr Grandpa Winky.
ben
ben
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southbaymoto
- Posts: 0
- Joined: Wed Mar 10, 2021 10:41 pm
We do not claim to be the "crank master". I am simply providing information on crank behaviors in relation to engine building 101. Jim or "winkie" is defiantly more educated than I as far as processes involved in rebuilding cranks for these machines. Jim stood up when nobody would and provided a much needed service to preserve these engines. A crank is a major piece of these engines. I respect and admire him and his vast knowledge of this process.
We do however claim to be the pioneers in dependability and performance for these engines. We use all processes available to build the most dependable and the fastest engines available. I have built an engine that has pulled a hole shot in every ATV national race it has been in for the NAC's racing team. We have also provided engines to many folks across America and through out the world for that matter.
Jim is the pioneer of rebuilding cranks. There are many parasites that try and steal technology that other folks have developed. I will not succumb to this type of bad business. Jim has taken chances and needs to be rewarded for his efforts and progress.
There are many solutions available to Cannondale owners to date. As long as there is a demand we will continue to provide our valued customers with quality, dependability and performance for these machines. We will also continue to supply you all with valuable information and support.
Dustin
SBM
We do however claim to be the pioneers in dependability and performance for these engines. We use all processes available to build the most dependable and the fastest engines available. I have built an engine that has pulled a hole shot in every ATV national race it has been in for the NAC's racing team. We have also provided engines to many folks across America and through out the world for that matter.
Jim is the pioneer of rebuilding cranks. There are many parasites that try and steal technology that other folks have developed. I will not succumb to this type of bad business. Jim has taken chances and needs to be rewarded for his efforts and progress.
There are many solutions available to Cannondale owners to date. As long as there is a demand we will continue to provide our valued customers with quality, dependability and performance for these machines. We will also continue to supply you all with valuable information and support.
Dustin
SBM
You hit the nail on the head Ben, with respect to crank failure. It's not my place to disclose what Jim (Big Winky) has discovered. If you want to know the details, call him and maybe he'll tell you. There are several highly respected engine builders out there, I think one of them owns this site, but the Winkster is the "crank man" and probably one of the most talented of engine machinists.
I've got a Big Winky 450 with all the goodies and it rips!
:head:
I've got a Big Winky 450 with all the goodies and it rips!
:head:
I would first like to thank South Bay for responding to this issue. I don't think they deserve any disrepect here for trying to help us all out, and share some knowledge. They are describing their way of doing this, and what they have found so far.
I am also going to send this thread to a couple of other engine builders and see if I can get them to respond.
I hope this is helping everyone understand what a major problem is with our engines, and that each problem can be overcome if we all work together in this. I know that I for one have way to much money invested in the Cannondale product to let it die, so when I find new tricks, or new fixes, I am not scared to share with others to try and improve it once again.
I am also going to send this thread to a couple of other engine builders and see if I can get them to respond.
I hope this is helping everyone understand what a major problem is with our engines, and that each problem can be overcome if we all work together in this. I know that I for one have way to much money invested in the Cannondale product to let it die, so when I find new tricks, or new fixes, I am not scared to share with others to try and improve it once again.
thats cool... in order to lose repspect... that means you had some respect to lose in the first place:)
reminds me of a line in the movie "pirates of the carribean"
british officer says"you are the worst pirate i have ever heard of"
pirate says " ahhh yes, but you HAVE heard of me"
if you havent seen the movie, check it out, great for the whole family
reminds me of a line in the movie "pirates of the carribean"
british officer says"you are the worst pirate i have ever heard of"
pirate says " ahhh yes, but you HAVE heard of me"
if you havent seen the movie, check it out, great for the whole family
Great info guys, thanks for sharing Dustin.
I know Winky has found (and corrected) some issues with the cranks that have nothing to do with balance. I sent him a brand new 02 billet crank that I knew was balanced to correct the other issues.
However, I will also back Dustins statements about the 03 crank not being in balance with the motor and that being overlooked at the factory. I was told the exact same thing by a very reliable source at Cannondale.
I also know that once the factory realized this was a problem, they corrected it by adding weight (tungsten to be exact) to the crank. They did this by adding the tungsten to a hole on one side of the crank.
I'm no crank engineer, but it seems to me that if you add weight to the crank all in one spot, you may have put the engine back in balance, but you just through the crank itself out of balance. I know you can't truly balance a single cylinder crank, but you should be able to balance the 2 halves on the center plane correct? How much out from side to side would you be able to feel, and how much would cause premature wear on the bearings?
And more importantly, does it matter in our application? or do we just care that the whole assembly is as close as possible?
I bet you guys would never guess I'm an analytical type
:eek:
I know Winky has found (and corrected) some issues with the cranks that have nothing to do with balance. I sent him a brand new 02 billet crank that I knew was balanced to correct the other issues.
However, I will also back Dustins statements about the 03 crank not being in balance with the motor and that being overlooked at the factory. I was told the exact same thing by a very reliable source at Cannondale.
I also know that once the factory realized this was a problem, they corrected it by adding weight (tungsten to be exact) to the crank. They did this by adding the tungsten to a hole on one side of the crank.
I'm no crank engineer, but it seems to me that if you add weight to the crank all in one spot, you may have put the engine back in balance, but you just through the crank itself out of balance. I know you can't truly balance a single cylinder crank, but you should be able to balance the 2 halves on the center plane correct? How much out from side to side would you be able to feel, and how much would cause premature wear on the bearings?
And more importantly, does it matter in our application? or do we just care that the whole assembly is as close as possible?
I bet you guys would never guess I'm an analytical type
:eek:
Jay,
I agree with Dustin's mention of semantics. Balance the crank, then balance or maybe a better word would be "optimize" the engine with respect to vibration. These are two separate procedures, although the first procedure must be done to yield the best results from the second procedure. Remember, the engine can never be balanced. I believe SBM and a few others fully understand this sequence and how to perform to gain the most reliability and then performance from these engines.
The Crank must be balanced and I might add "dynamically balanced" with considerations in multiple planes. If Cannondale added additional mass to a certain era of stock cranks, then they must have been made aware of a "crank balance" issue. The new aftermarket rods and pistons have been desiged with specific masses in mind to aide in minimizing the vibrations induced by the entire rotational and reciprocating assembly (crank, rod, pistion, rist pin, rings, rist pin bearing, rist pin clips, etc.) Starting off with an unbalanced crank only further compounds inherent engine vibrations.
I think what Ben was getting at pertains to catastrophic crank assembly failures due to other defects or deficiences in the manufacturing process. These failures are not primarily occuring due to unbalanced cranks or "non-optimized" engines. I think if your new stock engine survives 20-30 hours, it will most likely last as long as any other stock engine, although it won't last as long as an engine optimized by SBM, for example. SBM's engine will inherently have less engine vibration which in turn will have less negative effect on the cycle-life of the bearings and seals.
Tony
I agree with Dustin's mention of semantics. Balance the crank, then balance or maybe a better word would be "optimize" the engine with respect to vibration. These are two separate procedures, although the first procedure must be done to yield the best results from the second procedure. Remember, the engine can never be balanced. I believe SBM and a few others fully understand this sequence and how to perform to gain the most reliability and then performance from these engines.
The Crank must be balanced and I might add "dynamically balanced" with considerations in multiple planes. If Cannondale added additional mass to a certain era of stock cranks, then they must have been made aware of a "crank balance" issue. The new aftermarket rods and pistons have been desiged with specific masses in mind to aide in minimizing the vibrations induced by the entire rotational and reciprocating assembly (crank, rod, pistion, rist pin, rings, rist pin bearing, rist pin clips, etc.) Starting off with an unbalanced crank only further compounds inherent engine vibrations.
I think what Ben was getting at pertains to catastrophic crank assembly failures due to other defects or deficiences in the manufacturing process. These failures are not primarily occuring due to unbalanced cranks or "non-optimized" engines. I think if your new stock engine survives 20-30 hours, it will most likely last as long as any other stock engine, although it won't last as long as an engine optimized by SBM, for example. SBM's engine will inherently have less engine vibration which in turn will have less negative effect on the cycle-life of the bearings and seals.
Tony