Re: solex s3800 - question on clutch reassembly

• Author: BrianSolex (---.proxy.aol.com)
• brianc
• Date Posted: 05-08-08 19:51
• Attachment: 1210290707_bearing_puller.jpg

Hi Jeff,
It is quite possible that the rotor (the thing with the fins) is bent, especially if it looks to you like the bike has taken a fall. It is a common problem and the reason why it is recommended to have a crash-bar on the front:
http://www.lesolex.com/catalogue_fullsize/parchoc3800tournant2.JPG The rotor is sometimes called a flywheel, although this is not quite correct.
I don’t know anyway of straightening out a bent rotor. It will most likely need to be replaced. Sometimes, if the warpage is very small, you can see where the rotor is scraping the coil and grind some of the inside diameter away.
The main bearing is not easy to remove. It comes out the crank-weight side, not the roller side. The lip of the crankcase is rolled over the edge of the bearing. When Velosolex was still around, they would not even sell the bearing, shim and seal separately…the whole crankcase was replaced when the bearing went bad. That’s why you will not see these parts listed separately on any exploded motor diagrams:
http://documatheque.galet.free.fr/displayimage.php?pid=679&fullsize=1 The drive roller assembly was also replaced as a unit when it went bad. In the 3800 manual, you will not find instructions for replacing the bearing or drive-roller: http://documatheque.galet.free.fr/thumbnails.php?album=148
There was a special tool that electrically heated the crankcase and bearing to remove the bearing, when it was done by a VeloSolex technician. You can see the tool here:
http://documatheque.galet.free.fr/displayimage.php?pid=1044&fullsize=1
I always replace the bearing when I work on a motor, because it is always worn, and the rubber shield of the bearing, which is the actual seal for the crankcase, is always blown-out, leaking crankcase compression. I don’t have one of the special tools (yet), so here is basically how I do it. I pry out the seal from the drive-roller side after removing the crankshaft. (New seals and bearings are available from VeloCruz, but they are standard size seals and bearings that could be purchased at a bearing supply house.) I hold the crankcase in a vise with a special puller tool that I made, gently heat the crankcase to just the right temperature, then pull the bearing out using my special tool. If done correctly, the lip will neatly fold out and it can be peened over the new bearing. (See attachment.) The crankcase is very delicate and it melts and breaks relatively easily.
The oil seal that you see does not seal the crankcase. It is used as a wiper to keep dirt away from the bearing area. Notice how it is installed. (in which direction) As I said before, the rubber shield of the bearing is what seals the crankcase.
When installing a new bearing, don’t forget the shim that goes behind the bearing.
I use a small shop press to press in the new bearing, using some idler bearing Loc-tite, then peen the lip over the bearing edge, install a new seal, then press in the crankshaft all the way, carefully supporting the crankcase to avoid having it break.
On this page:
http://www.velocruz.com/store/engine_parts.htm the bearing is SPM90073 and the seal is SPM91456, but the bearing is, imo, over-priced.