My '59 Enfield /Indian 750cc Chief High Compression Build

[Scottie J]

Do you guys think I could make just a single one of these shocks work for me?  Obviously I don't want to overload the shock, but I also only plan on a bike/rider weight of 550-575#.  If you don't think one will be enough, I do have an idea to mount both shocks centrally like a mono shock, but it will be tight I think.

http://www.ebay.com/itm/13-330mm-Rear-Air-Shock-Absorber-Yamaha-Zuma-125-BWS-125-Moped-Black-silver-/180770535718?pt=Motorcycles_Parts_Accessories&hash=item2a16c37926&vxp=mtr

Scottie J

[Briz]

I think you'd be better off adding mounts to the swingarm to take conventional twin-shocks. That monoshock, without its linkage assy will make for a huge amount of suspension travel. You're not going motocrossing, 2-3" of travel is plenty.

[Scottie J]

Well if that's the case, I'm a little bummed that so many people gave so many contradictory answers.  Now I have 2 big ugly gussets welded to the frame and now I'm being told I shouldn't have done it and I should have went about it differently?  I feel like I just destroyed a piece of history.   

Scottie J

[Sumner]

Well if that's the case, I'm a little bummed that so many people gave so many contradictory answers. ...Scottie J 

Hey it is the Internet and opinions come and go and maybe all have something to offer one way or the other  .  Read them and then come up with "your" plan and go with it and consider that 5 years from now it might of evolved 180 degrees. 

I've got hundreds or hours of work into my lakester that I'm getting ready to cut out with the plasma cutter in an hour or so and will be making a huge change in direction.  These things happen  .  If you go down the road to making something work on the salt figure you are going to be modifying it so that it will never serve another purpose and it won't most likely ever return to its original condition. 

If you decide it is best to move the shocks (and I agree that aero is first and everything else takes a back seat to it) then cut out the new mounts and grind the welds down and you won't ever know you put them in there.

Good luck,

Sum

[Scottie J]

Hey it is the Internet and opinions come and go and maybe all have something to offer one way or the other  .  Read them and then come up with "your" plan and go with it and consider that 5 years from now it might of evolved 180 degrees. 

I've got hundreds or hours of work into my lakester that I'm getting ready to cut out with the plasma cutter in an hour or so and will be making a huge change in direction.  These things happen  .  If you go down the road to making something work on the salt figure you are going to be modifying it so that it will never serve another purpose and it won't most likely ever return to its original condition. 

If you decide it is best to move the shocks (and I agree that aero is first and everything else takes a back seat to it) then cut out the new mounts and grind the welds down and you won't ever know you put them in there.

Good luck,

Sum

This was the exact conclusion that I've come to.  It's not what I wanted to do but I think I'm stuck.  No big deal, you live and learn, just not looking forward to cutting those gussets off, it too long enough just trying to cut them initially.       But I'm beginning to wonder, how important IS rear suspension on the salt?  I know I've seen pics of Salt bikes that were rigid chassis.  How rough is the actual surface of The Salt?   Should I consider making some custom adjustable rigid struts?  Or should I find a way to mount those adjustable shocks I posted in in Reply 255?  I don't want to come across as clueless, I've built handfuls of classic hot rods, but when it comes to this Salt Aero stuff, well I am clueless.  Seems like every time I read something new on aeros it's almost contradictory to what I read the last.

So needless to say I'm a little confused.  This doesn't affect my motivation to build this bike at all, but I do agree with what you said Sumner.  I just need to take every thing that I've read and come to my own conclusion. Live, learn and build one season at a time.   

Scottie J

[SPARKY]

SJ   remember---you have no seat time - YET- on salt---as Sum said  It got to be ---YOURS --- you are the one who has to make it work.  Leave it in there, run it draw your own conclusion ---do what it takes to get on the SALT   then modify---may save one or two years as you are going to change it any way.  UNless you are running PP then you have fewer options!!

[Briz]

You aint wrong! its a learning-curve all right Scottie!
First time we went, we had twin-shock suspension. It didn't seem to make a whole lot of difference. This time, we made the frame rigid.
Doesn't hurt to have it, but making it rigid, its one less thing to worry about.

[Koncretekid]

I googled the following: "motorcycle rear drive dynamics" and got 46,000,000 results in .56 seconds.  Take your pick.

[Scottie J]

I googled the following: "motorcycle rear drive dynamics" and got 46,000,000 results in .56 seconds.  Take your pick.

My point exactly.   

[panic]

A mono has another advantage: you can prefab alternate linkage ratios (another set of holes) to play with the travel distance, lbs/inch rate and static height much more easily.

[Nortonist 592]

My thoughts on suspension is not to think too hard about it.  The salt is usually smooth and I don't think you'll be making 'Busa H.P. so I wouldn't get hung up on suspension.  My sidecar up until last year was rigid all round and never had a problem even when El Mirage was crap.  Lock it up solid and worry about making power.

[Koncretekid]

If anyone wants to study the dynamics of motorcycle drive mechanisms, I recommend the following reference:
http://books.google.ca/books?id=rJTQxITnkbgC&pg=PA216&lpg=PA216&dq=motorcycle+rear+drive+dynamics&source=bl&ots=DYjPEfcRrx&sig=fyA_2BJxEPoISoSGh3yS2VFs7kg&hl=en&sa=X&ei=9LIAU67BKamqyAHV1IGYDw&ved=0CGUQ6AEwBw#v=onepage&q=motorcycle%20rear%20drive%20dynamics&f=false

Don't dwell on it. It's complicated.

[Scottie J]

I'm thinking something like this.

http://www.ebay.com/itm/07-08-Honda-CBR600RR-CBR-600RR-Adjustable-Rear-Strut-/380444144668?pt=Motorcycles_Parts_Accessories&hash=item58943cf41c&vxp=mtr

Or This
http://www.ebay.com/itm/GSXR-600-Adjustable-Lowering-Strut-Solid-Strut-Busa-lowering-Strut-/271112505080?pt=Motorcycles_Parts_Accessories&hash=item3f1f9086f8&vxp=mtr

Scottie

[thefrenchowl]

Last 2 times I was at Bonneville, the bike was rigid end...

Smooth ride, but we felt maybe we weren't attaining the speed we should cause of the rigid end and tyre unhooking too often...

So for this year's Speed Week, I've re-fitted the shocks... We'll see...

Draw somewhere what your bike should look like and its contents and go from there.

Deviations are allowed, but in the main, try to steer straight to your design...

Remember. it's your bike and your balls on top of it once running, so just make sure you're happy with it, not what other guys think about it...

Patrick

[Old Scrambler]

I LOVE the multi-million chances you have for change

A few pages ago I suggested twin shocks...............but its your choice.  I reason (based on basic readings in suspension engineering) that the duty of shocks and springs is to keep the tire in contact with the surface at all times. BUT.........I have restricted my shock travel to about 2-inches and have them set quite stiff so I have minimal sag when I add my weight.

WE (Dave Murre and myself) made a plan and built accordingly with no direct experience at Bonneville. We were successful with a record on our first trip in 2011. We skipped 2012 (no $$$) and returned for another successful run in 2013. We are building another bike for 2014 and hope to be successful with both bikes.

Plan your work...........and work your plan.  Somebody said that in a text book.