Leaf spring rear-end!!!

[LikeMike64]

Having the front of the engine elevated while retaining the same hight at the rear of the engine (like on that racing wing) would reduce the angle at the U-joint.
Lowering the rear of the engine while maintaining the original front hight will put a sharper angle on the U-joint of the drive-shaft.
Remember, the pivot point of the rear suspension is centered on the U-joint of the drive shaft. As that pivot point goes down (or the rear wheel goes up) the angle increases. I too am concerned about the drive shaft angle.

[robin1731]

Having the front of the engine elevated while retaining the same hight at the rear of the engine (like on that racing wing) would reduce the angle at the U-joint.
Lowering the rear of the engine while maintaining the original front hight will put a sharper angle on the U-joint of the drive-shaft.
Remember, the pivot point of the rear suspension is centered on the U-joint of the drive shaft. As that pivot point goes down (or the rear wheel goes up) the angle increases. I too am concerned about the drive shaft angle.

And it will only get worse when riding it. It looks to me like the bike may be a little low. Maybe with those springs though it won't move much, I don't know. I still wonder how it's going to ride with no shocks. Can't wait for a ride report.

[Fred Camper]

Looking much too low to corner in the back currently, so more adjustments may be in the work. Remember, the springs just came back.

[Old Fogey]

I'm guessing that we are not seeing the whole deal. For a start there has to be a solid point to bend the spring around and I don't believe that the allen screw and rubber is supposed to be it! That looks to me to be the high point of travel buffer rubber.
This would have maybe been an easier install if the frame end of the spring had been held solid and the spring used as a quarter elliptic. No need then for another bend point.

[Sacrilege84]

No No NO.....she dropped when i took her off the stand......waaaaaay to low. My plans are for the drive shaft to be level at riding rest height. So that mean that the bike will be about 2 inches above where it is in that picture. Funny thing about stock, the drive shaft is really elevated at the stock position. And i know the travel wasnt THAT much! But anyhow.....the fulcrum point hasnt been installed yet....the amount of force on that spot where the spacer is, is amazing! So the appropriate amount of steel is gonna be applied and still be adjustable. But, I dont know about yall, I think it is turning out pretty dog gone good!

Here is where i think it is gonna sit-------->>>>

Cant pull the file...nxt post!

[Sacrilege84]

Gotta clean the lens on my camera huh? It has a small incline in the drive shaft but less than stock in the opposite direction.

[robin1731]

Is that the ride height?

[Sacrilege84]

Pretty close Robin...but the way i am installing the fulcrum block it will be adjustable. I am gonna put multiple holes so that i have some adjustment. Got to get that center stand out of there!!! I think that will give a better idea of the height. I am not ginna use it anyway! Need one?

[sunnbobb]

Whew! you had me worried! LOL

[LikeMike64]

Whew! you had me worried! LOL

Me too!!!

[Sacrilege84]

Crazy....not stuuuupid! Should get the other spring by the end of the week!!! Radiator shop is workin on the converted 4 core heater core.....should fit nicely in the tail of the bomb tank. Also, got a new, much better lookin' fan for the cooling motor. I hope to have the tank mocked up in the next couple of weeks.

[Sacrilege84]

Old Fogey.......You are right that fixed point attachment at the front of the spring would have been easier. But....with the forces involved it is better to split!!! The upward force of the spring is divided between the rear frame section and is inversely applied down at the attachment point near the swing arm pivot point. Plus the next part of the build will show why i am soooo worried about the geometry of the rear frame section. Its cuttin time!

[Sacrilege84]

Alright....so i kept messin around with the seat pan and could never get it to look right and function properly. So i did what any sensible man or woman would do!!!!! Cut off the rear upper frame section. Right?!?

Boy it sure is alot easier to make it work now!

I am going to loop the rear to cut off points together. Then i am going to run a true backbone down from the front cross member near the forks down along the topside of the frame and curve it up to mount the seat. As Emeril would say "Bam" problem solved! What do yall think about the mock up?

PS this setup should transfer the upward force created by suspension into a linear force into the cross member.....not to mention my kidneys!

[Fred Camper]

Seems like your backbone will need some cross braces to not become a suspension member, but I suspect you are way ahead of me on that. I am still trying to understand where that radiator is going...

[robin1731]

Ok, if I see this right. You have the hoop above the tire running from one side to the other. Thats good. In my opinion you need to from where that tube bends and goes forward. This needs to be tied in to the frame near the engine mount. At least in one location. Maybe you are going to do this. If not the load from the suspension is going to just push that pipe up and buckle it over time. Again, if I'm looking at it right.