78 Cyclone Rear Suspension info please?

General topics related to John Deere Snowmobiles
Liquifire 4/6
Posts: 1035
Joined: Thu Mar 08, 2007 1:00 am
Location: Roblin, MB

78 Cyclone Rear Suspension info please?

Post by Liquifire 4/6 »

During the last couple months, I've been working on a 78 Cyclone that I re-powered with a 488 Indy Trail engine. I haven't restored the sled to pristine condition yet but have instead just gone through it very thoroughly to ensure it is a reliable machine. I went completely through the rear suspension making sure all the pivot shafts turned freely and that all bearings were good. Nothing bent or busted in it anywhere and it looks like the suspension should work perfectly.

But, it seems to sit awfully low in the rear end. Maybe that's just the way these things were? With the sled raised on a stand, the rear end of the suspension still sits well up in the tunnel while the front portion of the suspension seems to stick out of the chassis the way one would expect it to. This is the only 78 Cyclone I've ever seen up close and I know the rear suspension in the 1978 models were unlike any other years. Did I do something wrong or is it just normal for that year?

I'l attach a picture showing it up on the stand but it's a bit hard to see. If there are any tips or suggestions anyone can give me on the 1978 suspensions, please let me know. Also, has anyone lowered the mounting point for the rear torque arm below the stock position? If you did, did you also have to lower the mounting point for the front torque arm?
Attachments
IMG_7154.JPG
Peter from Roblin, Manitoba
Liquifire 4/6
Posts: 1035
Joined: Thu Mar 08, 2007 1:00 am
Location: Roblin, MB

Re: 78 Cyclone Rear Suspension info please?

Post by Liquifire 4/6 »

Just thought I might as well post a few of pictures on the engine installation. We only have an inch of snow here so my testing thus far has been limited to a couple of short runs on the lawn but I have to say, this thing really seems to scoot along!
Attachments
IMG_7158.JPG
IMG_7156.JPG
IMG_7155.JPG
Peter from Roblin, Manitoba
User avatar
ihengineer76
Posts: 467
Joined: Sat Jan 19, 2013 11:53 am
Real Name: Tom Rehberg
Location: SC Wisconsin

Re: 78 Cyclone Rear Suspension info please?

Post by ihengineer76 »

Is the rear shock factory? It looks like it isn't fully extended or is too short. Can you manually extend the suspension any further?
1976 Liquidator - 970 mile raced sled
1975 340/S - I-500 raced sled
1978 440 Liquifire
Liquifire 4/6
Posts: 1035
Joined: Thu Mar 08, 2007 1:00 am
Location: Roblin, MB

Re: 78 Cyclone Rear Suspension info please?

Post by Liquifire 4/6 »

ihengineer76 wrote:Is the rear shock factory? It looks like it isn't fully extended or is too short. Can you manually extend the suspension any further?
As far as I can tell, it is the correct shock and it operated smoothly and travelled it's full range when I had it removed from the suspension. It is stamped AM 54601 Gabriel and when I looked at the John Deere parts site, that is the part number it calls for on the 1978 Cyclone. Something just doesn't seem right with the way it looks. And no, I can't seem to manually extend the suspension any further. I'll post a pic of the rear torque arm in case anyone can figure out what's wrong based on that.

The springs do seem to be under a fair bit of tension with the sled just sitting there with zero weight on the seat.
Attachments
IMG_7166.JPG
Peter from Roblin, Manitoba
AirborneX4Special
Posts: 1450
Joined: Sat Jan 30, 2010 10:54 am
Real Name: Pat
Location: N. IL

Re: 78 Cyclone Rear Suspension info please?

Post by AirborneX4Special »

When you push it downward manually does it return to where it is in the picture, or is the picture showing full extension of travel? It just seems a bit compressed, as if the machine were on the ground with someone sitting on it for a photo op. I have seen worn out shocks fail to hold the suspension at full extension with no load.
Liquifire 4/6
Posts: 1035
Joined: Thu Mar 08, 2007 1:00 am
Location: Roblin, MB

Re: 78 Cyclone Rear Suspension info please?

Post by Liquifire 4/6 »

The picture is showing it at what seems to be it's full limit of travel. My brother has a 77 Cyclone with the older style suspension which I would assume should have less travel. But this 78 seems to have less travel than his 77? I am going to yank the suspension back out of the sled tomorrow and take a closer look at it on the bench. Maybe I can post some pictures of it on the bench so that you guys can hopefully see if I assembled something incorrectly. And thanks for the input, guys!
Peter from Roblin, Manitoba
User avatar
fast823
Posts: 117
Joined: Tue Jun 30, 2009 3:31 pm
Real Name: Trevor Fast
Location: MN

Re: 78 Cyclone Rear Suspension info please?

Post by fast823 »

Anymore info on motor swap? I am saving a cyclone chassis to do same. I was hoping to just put in the older Polaris suspension at same time.
18 and counting
Liquifire 4/6
Posts: 1035
Joined: Thu Mar 08, 2007 1:00 am
Location: Roblin, MB

Re: 78 Cyclone Rear Suspension info please?

Post by Liquifire 4/6 »

I ended up removing the rear suspension from the sled last night and I could see no way that I could have erred in it's assembly or installation. Everything seemed to operate the way it should. This morning, I downladed a manual and took a look at the section pertaining to the rear suspension of the 1978 models. The picture they show of the suspension installed in the sled looks identical to the way mine looks. The rear portion of the skid appears to be tucked too high up into the tunnel while the front portion of the suspension hangs down lower the same way as mine does. So it seems there is nothing wrong with my suspension. It just doesn't look right to me and I am seriously considering making a new lower mounting point for the rear torque arm.

The new hole would have to be below the running board as there is not enough space to drill a new hole below the existing hole since it is only about an inch above the running board. That would put the new rear hole almost 2" lower than the stock rear hole. Would I need to also lower the front hole? And if so, would I need to go the same 2" lower or would it only need to be lowered slightly from stock? Some of you have likely lowered rear skids on these sleds so any opinions would be appreciated. My main concern would be that I not put any undue stresses on the track. Here's a pic from the manual showing the stock set-up
Attachments
IMG_7168.JPG
Peter from Roblin, Manitoba
Liquifire 4/6
Posts: 1035
Joined: Thu Mar 08, 2007 1:00 am
Location: Roblin, MB

Re: 78 Cyclone Rear Suspension info please?

Post by Liquifire 4/6 »

fast823 wrote:Anymore info on motor swap? I am saving a cyclone chassis to do same. I was hoping to just put in the older Polaris suspension at same time.
Might be best if I just start a new thread on the motor swap. Not sure if I'll have time today but I'll try
Peter from Roblin, Manitoba
harleysportster
Posts: 2965
Joined: Thu Jul 14, 2005 12:00 am
Real Name: Pat Scott
Location: Southeast Pa.

Re: 78 Cyclone Rear Suspension info please?

Post by harleysportster »

Pm me your email and I'll send some pictures of my stock 78 cyclone suspension.
'76 440 cyclone
'76 440 liquifire
'78 440 Cyclone
'75 JDX8 (sold to a member here)
'78 Liquifire(CrossCountry Clone)
'80 Liquifire(sold)
Liquifire 4/6
Posts: 1035
Joined: Thu Mar 08, 2007 1:00 am
Location: Roblin, MB

Re: 78 Cyclone Rear Suspension info please?

Post by Liquifire 4/6 »

harleysportster wrote:Pm me your email and I'll send some pictures of my stock 78 cyclone suspension.
PM sent. Thanks a bunch!
Peter from Roblin, Manitoba
harleysportster
Posts: 2965
Joined: Thu Jul 14, 2005 12:00 am
Real Name: Pat Scott
Location: Southeast Pa.

Re: 78 Cyclone Rear Suspension info please?

Post by harleysportster »

Liquifire 4/6 wrote:
harleysportster wrote:Pm me your email and I'll send some pictures of my stock 78 cyclone suspension.
PM sent. Thanks a bunch!
As it turns out, it is easier sending thru this format. It looks like your suspension is normal as compared to mine.Image
'76 440 cyclone
'76 440 liquifire
'78 440 Cyclone
'75 JDX8 (sold to a member here)
'78 Liquifire(CrossCountry Clone)
'80 Liquifire(sold)
harleysportster
Posts: 2965
Joined: Thu Jul 14, 2005 12:00 am
Real Name: Pat Scott
Location: Southeast Pa.

Re: 78 Cyclone Rear Suspension info please?

Post by harleysportster »

Here is some eye candyImage
'76 440 cyclone
'76 440 liquifire
'78 440 Cyclone
'75 JDX8 (sold to a member here)
'78 Liquifire(CrossCountry Clone)
'80 Liquifire(sold)
Liquifire 4/6
Posts: 1035
Joined: Thu Mar 08, 2007 1:00 am
Location: Roblin, MB

Re: 78 Cyclone Rear Suspension info please?

Post by Liquifire 4/6 »

harleysportster wrote:Here is some eye candyImage
Yes, the first picture you posted looks exactly the same as my Cyclone so I guess mine is normal. But what's up with this second picture? Is that a newer 80-84 Liquifire track and suspension in a 78 Liquifire? I like the look of that!
Peter from Roblin, Manitoba
harleysportster
Posts: 2965
Joined: Thu Jul 14, 2005 12:00 am
Real Name: Pat Scott
Location: Southeast Pa.

Re: 78 Cyclone Rear Suspension info please?

Post by harleysportster »

That is my version of a 78 cross country clone using a 1980 skid and an Arctic Cat all rubber track.
'76 440 cyclone
'76 440 liquifire
'78 440 Cyclone
'75 JDX8 (sold to a member here)
'78 Liquifire(CrossCountry Clone)
'80 Liquifire(sold)
Post Reply