EricMichael
New member
oh ok I understand that now!!heavier weight will provide more force but will be diffrent cause the weight is in diffrent areas of the weight. I see the 8dn-00 has less of a shift curve, but I still dont understand what that means?Does that mean the belt wont rise on the primary as quick as the 8dn-20, but hte shift curve towards the end is the same. So in all reality according to the charts the 8dn-20 would be an overall better weight than the 8dn-00. BUT the 8dn-00 shows more tip weight so wouldn't that mean it should provide better top end than the 8dn-20? I'm goign to buy either set this weekend and its looking like the 8dn-20 would be an overall better weight.I'll be waiting to hear more from you about the helix and these two weights. I think i learn better from you than my teachers in college haha...thanks alot
Eric
Eric
a 8dn-20 is a hard weight to beat, it does all of it to a decent degree, acceleration, trail, topend with the right other parts with it.
The 8dn-00 is the mac daddy of topspeed weights, but you wont get a super aggressive holeshot with it , look at where the weight is placed in it, in the tip, so this means when the weight is at full swing its providing the most amount of belt squeeze, this equates to how fast your going.If all your interested in doing is top speed radar runs heres your weight, you can trail ride it with some decent results but the 8dn-20 works better over a wider variety of conditions.
He who squeezes the belt the most with the greatest amount of efficiency wins!!!
you are correct on your basis of the shift curve profiles.
The 8dn-00 is the mac daddy of topspeed weights, but you wont get a super aggressive holeshot with it , look at where the weight is placed in it, in the tip, so this means when the weight is at full swing its providing the most amount of belt squeeze, this equates to how fast your going.If all your interested in doing is top speed radar runs heres your weight, you can trail ride it with some decent results but the 8dn-20 works better over a wider variety of conditions.
He who squeezes the belt the most with the greatest amount of efficiency wins!!!
you are correct on your basis of the shift curve profiles.
EricMichael
New member
Now, the best thing to do if i was to buy the 8dn-00 is to take the weight without any rivets and try it with my 51/45 helix and green secondary, hauck orange primary and see where my rpms are. I would want the rpms to pull to my peak torque and climb to my peak horsepower for the pipes correct? So by tuning the primary with the correct rivets you could make that helix work right? On an average, you must know what people run in those weights with a piped viper. If you do know that would help so i would know if i'm going in the right direction when i'm out on the lake tuning...if not thats ok too...i'm glad i learned this much in one day...i realize theres alot more to learn still...if you have any more info on the helix's and how they work that would be nice to learn also...thanks
EricMichael
New member
mr.viper is it required to run the 15.6 rollers with the 8dn's?
No, its not required to run any size rollers on a stock yamaha weight, its just that it changes the way the weight acts and it also changes the rpm in which you will engage at and your shift rpm as well. Smaller rollers increase the weight force, but lowers the engagement speed and shift speed, larger is the opposite.
I will tell you the same thing I tell people when they call asking for help, set your sled up for the riding you do 90% of the time and just deal with the other 10% win or lose!!!. Setting your sled up for the 10% will yield a machine you will grow to hate and you wont enjoy riding it.
If you want to set your sled up for differnt racing set ups be prepared to spend some money on various helix's,springs and clutch weights, you cant use the same helix and springs and just change the weight to do drags,top speed and trail ridng, its the combination of the parts that gets you the results. There is alot of differnt combo's to get there. I have 20 helix on my wall , about 50-60 clutch springs from all differnt manufactures and a box of weights and rivets.
I will tell you the same thing I tell people when they call asking for help, set your sled up for the riding you do 90% of the time and just deal with the other 10% win or lose!!!. Setting your sled up for the 10% will yield a machine you will grow to hate and you wont enjoy riding it.
If you want to set your sled up for differnt racing set ups be prepared to spend some money on various helix's,springs and clutch weights, you cant use the same helix and springs and just change the weight to do drags,top speed and trail ridng, its the combination of the parts that gets you the results. There is alot of differnt combo's to get there. I have 20 helix on my wall , about 50-60 clutch springs from all differnt manufactures and a box of weights and rivets.
vipertripplexxx
New member
a heavier weight, does not always provide more force. it has to do with angle of contact on the roller, this is why changing roller size changes force without a weight increase. It all has to do with angle of contact on the roller. a weight with alot of tip arc has just as much force as a heavy weight with less arc. If you think that a 8bu-00 designed for an 800cc machine has less full shift force than the 8dn-20, you are mistaken. The tip profile is what is giving you more side force, with less weight. The reason no one uses them for top speed running is they are much harder to tune with this type of profile at the tip. Small increase in weight causes large increase in force. Top speed is all about tweaking, this makes it hard to get the right combo. I guess I like the lighter weights, they can give you the best of both worlds, but it takes some time.
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EricMichael
New member
So what your saying is i'd be better of using the 8dn-20's and setting it up from there...it would probably be much more trailable with nice top end?Will I be able to tune those 8dn-20 weights with a 51/45 helix or is it a waste of my time?
I prefre heavier weight.I guess it's a personal prefeance.I test on timers and radar for drag racing and radar running I always had better results running more tip weight and less helix than more helix and less weight about 90 % of racers will tell you the same thing.
EricMichael
New member
Mr.viper, you say the 8dn-20 is a hard weight to beat, it provides good on and off acceleration and some good top speed...that sounds more like what i'll need for the trails here and lake runs..It wouldn't be wise to get the 8dn-00 and have to change over to the 8dn-20s if i didn't like them on the trail. I notice alot of people run the 15.6 rollers but what about all the other rollers that i see on the tech page...is this the one that most people prefer?
This is where you have to get out and test, try the 14,5 rollers see what kind of shift curve you get, try 15's, then 15.6's, there is no 1 way to do anything in clutching. If we both had the same sleds, same motor set ups and tracks etc. You clutched your sled 1 way with 8dn-20's, and say I did mine with 8dn-00's, we both may have a top speed of 100mph..BUT.. 1 of them will do something better then the other one will and thats the differance, 1 may accellarate faster up to the same topspeed, 1 may have a better backshifting characteristic.
Steve, Good point, I understand all about the angles of contact on rollers, but we are trying to teach them basics here.They need to learn profiles, then venture out into the deeper waters with rollers,springs,multi angle helixs. The curvature out at the tip also provides less rpm in high ratio. (( This is the very reason why you have to use a very shallow helix finish with a 8bu,8ca,8ab on topend!))It doesnt matter what size the engine was the weight was built for, thats why they are adjustable with rivets, and if need be... grind weight off of them, sometimes add weight with welding on them. Its just part of the key to finding the amount of weight your paticular engine can pull with your gearing,springs and helix combo, and be efficienct doint it!
Steve, Good point, I understand all about the angles of contact on rollers, but we are trying to teach them basics here.They need to learn profiles, then venture out into the deeper waters with rollers,springs,multi angle helixs. The curvature out at the tip also provides less rpm in high ratio. (( This is the very reason why you have to use a very shallow helix finish with a 8bu,8ca,8ab on topend!))It doesnt matter what size the engine was the weight was built for, thats why they are adjustable with rivets, and if need be... grind weight off of them, sometimes add weight with welding on them. Its just part of the key to finding the amount of weight your paticular engine can pull with your gearing,springs and helix combo, and be efficienct doint it!
Rambunctious
New member
eric
seems you really want what i want/have
better accelleration and good top end for the occasional lake race.
the 4.5g rivits in stock swing weights, 51/43 helix does the trick with www primary and stock red secondary springs for me.
I also machined the inner flangeon the helix, allowing it to shift out more ( not sure if it actually does, never marked it to see)
an easy job for someone with an endmill. if you buy a 51/43 from cbperformance, they can do it., or any machine shop
seems you really want what i want/have
better accelleration and good top end for the occasional lake race.
the 4.5g rivits in stock swing weights, 51/43 helix does the trick with www primary and stock red secondary springs for me.
I also machined the inner flangeon the helix, allowing it to shift out more ( not sure if it actually does, never marked it to see)
an easy job for someone with an endmill. if you buy a 51/43 from cbperformance, they can do it., or any machine shop
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your running a srx at 8500rpm he is running a viper at 9000rpm, not the same set ups, his motor doesnt have the same power peak and curve of your srx, so the set ups will be differnt.
EricMichael
New member
thanks for your help mr.viper, i'm going to get the 8dn-20's friday or sat and try the bigger rollers and see how it works...i'll try tuning it to my helix first and if that doesnt' work my friend has many other helix's that may work. We will be going out on the lake this weekend, i'll let ya know how i do against them now compared to when i ran them with the 8ca's.