Cross Country Cyclone build

[400brian]

I have changed the title of this thread once again to reflect what I am doing.

With the grandson's 78 Spitfire down to a little wiring work and tuning on the snow ( if we ever get any ), and with the 78 LF CC clone largely finished last February, I am really on a roll.

After riding the 78 LF in st Germain last Feb as we had no snow here, I found I really liked the CC suspension and the 1 1/2" thicker seat it had. I like the higher seating position, and the additional foam under my backside.

As we were finishing up the Spitfire, it occurred to me that the grandson will most likely out grow the Spit fairly quickly, and that I have a 76 Cyclone sitting in the shed that is pretty much in the same condition as the Cyclone I build for my wife back in 2023. Further, I have some parts left over from the 78 CC clone build and it is all fresh in my mind...I could build a CC Cyclone!

A 340 Cyclone with a CC suspension, gas tank and seat, would have the ride of the 78 CC without all the weight and added complexity of the liquid cooling.

The CC clone suspension I displayed at the Badger Steam and Gas Show is the suspension that is planned to go into that sled.

A couple of years before he passed, the late Jon Carlson told me he had ideas for one more sled. He did not share the specifics, but I remember he had talked about the idea of a Cyclone based race sled. I plan to try a version of that idea.

[400brian]

I had basically just roughed the suspension out because I wanted to display it at the Badger Steam and Gas show.

The test fit in the track indicated I was really close, but I have it back on the bench for a little more tweaking.
The front is right on at 9" wide, the rear is about an 1/8" wider. I have a good idea what is causing that. There is also a slight twist in the rails.
The previous suspension had that too, but altering the tightening sequence resolved it. So far that has not worked with this one.
Right now the plan is to get the width correct, then clamp the rails flat to the table to see if that will show me where that misalignment is coming from.

The grandson and I are contemplating on what we can throw out of the shop to gain more secure sled storage, there is never enough space under roof.

[400brian]

The suspension has been disassembled for final tweaking.

I taped a clean sheet of freezer paper onto the bench, drew a centerline, then drew lines where the track windows and drive lugs are located.
I am shooting for a consistent 9" rail width measured outside to outside of the new hyfax. You can see where I am using 3/8" threaded rod to hold the rails more or less in position.

I began at the rear by shortening the small shaft that bolts between the rails to obtain a rail width of 9" based on the ink lines I had drawn. I then adjusted the threaded rod inserted at the top of the towers and measured how long the lower shaft of the front arm needed to be. Originally that shaft has a length of 7 3/4". Using my benchtop belt sander, I carefully brought it down to 7 1/2", and did a test fit. I was satisfied with the result.

I moved forward to the aux idler brackets. I used a square to determine how plumb they were to the rails. The left was good, the right left a bit to be desired, I suspect that this is where the twist in the rails is coming from. Measuring the distance, I find the current length of the shaft I had in it should be good. I reinstall it and tighten everything up, and the skid remains flat on the table. I don't really understand that.

I turn the skid crossways to the table and the twist is back, either the skid is twisted, or my table is.

I moved some washers around to allow the rear arm to be bolted into the plastic bushings at the top of the rail bracket. That doesn't seem to affect anything twist wise. The twist I am seeing ( when I see it ) is about 1/8".

The lower tube in the front arm will now need to be shortened to match the shorter shaft, and I will probably have to adjust the length of the teardrop spacers mounted between the rails and the center rear idler.

[400brian]

For the most part, to narrow the suspension from a width of 9 1/4" down to 9", you shorten all the shafts that control the rail spacing a 1/4".
To narrow the rear arm connection to to the rails, you simply move washers from one side to the other, and to fit the rear axle between the rails, you remove two 1/8" washers, and add them back behind the outer idlers to properly space the idlers in the track.

I am learning a few things as I do this second suspension. As usual, you are not the first person to have this stuff apart at this point in time, and you may have parts missing or assembled incorrectly. The two 1/8" thick washers that Brock sent with the axle kit, I omitted as the simple way to take 1/4" out of the between the rails assembly. On the previous suspension build, ( I had to go back and look at the photos I took to see what I had done ) I had placed the washers between the teardrop spacers and the rail bracket. This had required me to shorten the teardrop spacers, and looking at this now, I guess I didn't have to do that, I could have just left the washers out. On this suspension, you will see that I ground a bevel into the end of the teardrop spacers where they come up against the center wheel. I did not do that previously, but it seemed like a good idea now.

On the rear arm, I moved an 1/8" washer on each side so that both were now against the outside arm, thus moving the rail bracket 1/4" closer together. On this arm I did the same thing, but I installed a 1/16" thick washer because 1/8" really didn't fit. I have no good explanation for that, but everything fits tight and looks like it will work.

To finish out the rear axle; It would make sense that the 1/8" washers I deleted from between the rails would now need to to be added back into the assembly between the rails and the outer wheels to get the wheel spacing right. Right now I have 1/16" washers between the wheels and the square spacers that fit into the rail bracket. Setting the skid onto the table and looking at where the wheels land on what I have drawn out, it looks good. I will not declare victory until I set it into the track and confirm that.

[400brian]

To finish the suspension I moved forward to the lower shaft of the front arm, ( the 3/4" shaft between the towers ).

The shaft had been shortened the amount needed , but the tube on the front arm still needed a bit more removed because it didn't swing freely.
I used the shaft as a guide to get the tube squarely trimmed, and used a 120 grit flap disc on the angle grinder to carefully trim the tube back evenly on each side to allow the shaft to protrude a bit.

BTW, there are two shafts that have been used. The original 78 CC and early 2nd gen LF used a hollow shaft with a long 3/8" bolt to tie the rails together. A later design used a shaft drilled on each end and a 3/8" bolt threaded into it from each side. In each case the shafts I have seen are aluminum.

Also, be aware that you will have to grind a chamfer into the inside forward edges of the towers to make clearance to prevent contact by the front arm.

A test fit showed that the front arm now swung freely and was just clearing the towers .

The aux idler shaft and wheels were installed as they had already been deem good.

The front shaft with the spools for the front springs is another item that has changed. The CC shaft was aluminum drilled for a bolt from each side, and holes for roll pins to locate the spools. On the previous build I used an aluminum shaft drilled on each end, but allowed the spools to freely float as per the 80+ design.

The shaft Luke sent me was a hollow steel shaft ( 7/8" OD 3/8" ID ). This requires a long thu bolt. At the moment I have a piece of Redi-rod installed.
The shaft I had removed from the donor suspension was steel drilled and tapped on each end. It had grooves worn into it, apparently from the springs wearing through the spools and then into the shaft ) so I chose not to use it.

The last item I looked at was the position of the side idler wheels. Again, you would think they would need to be moved out 1/8" on each side to put them back out where they belong, but like the rear axle, a 1/16" shim on each side seems to put them in a good place. A test fit in the track will resolve that.

The last thing I need to complete the suspension is a Fox gas shock. This is not for the faint of heart, the last one I purchased set me back $250.
I had been resisting that, but after riding the wife's 76 Cyclone with the 78 production suspension in it with a hydraulic shock ( and bottoming out on every bump ) I had been convinced I needed more damping. Riding the 78 LF with the CC suspension with the Fox shock in it was a huge improvement, so this one will get one as well, but it bites.

[jdjock]

I have a used CC track from one of Roger Janssen’s race sleds. Pm me if interested.

[jdjock]

Message sent

[400brian]

The Carver gas shock arrived a bit less than a month after I ordered it.

That was pretty much the final piece I needed to complete the suspension. The only pieces I might consider adding are the second pair of auxiliary idler wheels between the rails that were offered for the CC.