ColonelJLloyd 

I took my Suntour Cyclone RD apart to replace the worn out jockey wheels with Bullseye replacements. I'm having trouble reassembling it and getting the spring set correctly. How do I go about reassembling this thing? The RD looks like this.

FBinNY 

Looks OK in the Photo, or was that before you took it apart?

Where are you having a problem? I assume the pulley swap was straightforward since that's simply a matter of pulling out the two screws which hold the pulleys and inner plate.

ColonelJLloyd 

The RD in the photo is for reference. I don't think it's necessary to post a photo of the actual RD. I need to know how to reassemble the spring/bolt for the upper pulley. I can get it back together without issue, but the spring doesn't have proper tension (if any).

dedhed

Poke around at yellow Jersey.

https://www.google.com/imgres?imgurl=...ed=0CBsQ9QEwAQ

ColonelJLloyd 

That's a useful link, but "where the pieces go" is not my issue. I need to know how to reassemble the RD so that the spring has proper tension.

Can a mod move this to C&V, please?

FBinNY 

It's been a long, long time since I rebuilt one of these, so I went to Deb's old Zebrakenko (still going) to look at her Cyclone derailleur for a refresher. Alas, it's a slightly different generation and uses a fixed stop cam and "B" screw rather than upper body spring.

If my memory serves, and if I don't offend you by stating the obvious, the key lies in engaging the spring both in the body and stop cam, then rotating the cam to load the spring before seating it.

If no one comes by to help, you can phone me some afternoon, describe what you have to refresh my memory, and I'll see if I can talk you through.
I don't want to publish my number, so email me at info at the site below my signature and we'll set something up.

ColonelJLloyd 

Precisely. Therein lies my problem.

FBinNY 

Like I said it's been a while and I need a refresher. Is there any way you can post a photo of the parts laid out on a table, showing the back of the body, bolt, spring and cam. That should jog my memory and I might be able to help.

ColonelJLloyd 

Here's some photos. Getting the RD back together is not the problem, but rather getting the spring set in the housing so that it provides the proper tension. I did not disconnect the spring from the bolt at the upper part (near the head of the bolt). I'm wondering if it that is the key, but I'm hesitant to disconnect it there for fear I may not be able to get it back in.

TireLever-07

HI Lloyd, I had a Suntour VGT rear Derailler for 14 years, on a Motobecane.It should not be that tough to get it back together etc. I got "Richard's Bicycle Book" circa 1982. Its got exploded line drawings of ,,,just about everything. I got an 8 speed Shimano Olivata rear der. to work on a 1986 Centurion,friction,orginal down tube levers,,well I gotta go ride. Chris

FBinNY 

It isn't a full moon, so it must be the heat, either that or I simply spaced out. I mis-read your reference to the the upper pulley spring as a reference to an upper body spring. The pictures clarified it completely. (definitely worth 1,000 words in this case)

First of all the leg of the spring should be at 90° to the coil, but they often break when you try to straighten so leave it alone for the moment, and see if it'll work as is. Now assemble the cage onto the body guiding the leg of the spring into the space at the bottom of the body, passing the bolt through the pulley as you go and tighten. At this point do not screw in the stop peg (the small 3/16" dia. threaded part). Tighten everything and make sure the cage rotates and returns to it's neutral slack spot (typically upside down) freely. Now wind the cage counter clockwise (looking from the outside of the bike) far enough that the stop peg hole is past the bumper on the back of the body, and screw in the peg while holding it there.

That's it. Chain tension will rotate the cage counter clockwise against spring tension, and when the wheel is removed the RD cage will rotate until the stop peg hits the bumper.

BTW- one of the issues with this particular derailleur is that the stop peg would fall out and the idler cage would rotate almost 360° making a tangled mess whenever the wheel was removed.

ColonelJLloyd 

The fact that it wasn't 90 degrees to the coil wouldn't allow me to fit it in the little hole so I attempted to bend it. It broke.

Anyone know of a source for a replacement spring? Should I be able to canabalize an older Suntour RD and rob the spring?

FBinNY 

Been there, done that, that's why I warned you.

Sun Tour used the identical spring in a number of derailleurs of that generation, so you might be able to canibalize one from a different model. Be sure you find one that is keyed to the bolt and bottom of the lower body, many are keyed to the top of the lower body and the idler cage.

BTW- if you're skilled with a torch, you might be able to heat the coil one turn back, and bend up a new leg. keep the heated zone very local, then quench in water or motor oil. Be sure to work roughly one full turn back so the orientation is right.

ColonelJLloyd 

You gave me fair warning and great directions. Unfortunately, the spring wouldn't work as it was and I had to give it a try. C'est la vie.