Speedo spring

[conbs]

Ian,

I am a little late to the party but, if you don't have it back together yet....

The shaft that the needle is on has two lube points. The top one is right behind the needle and plate. Brass IIRC. The second one is at the bottom end of that shaft down inside the cup. The shaft comes to a point and rests inside a bushing that is in the lower cup. The outer cup is magnetized and as it turns it pulls against the inner cup which pushes against the spring. The more revolutions, the more the magnet pulls on the speedo shaft and the higher the needle registers. But, the top shaft does not "spin", so, it HAS to have a clean and well-lubed bushing at the bottom of it. You likely still have some gunk down in that bottom bushing. if you don't get it cleaned out you can expect increasing trouble. You can take the speedo frame apart and pull the top shaft out of the lower cup to clean things up. Be very careful you don't tweak that spring. BTW it was calibrated when it was staked so that it pushes back against the spinning cup with the right pressure so that your speedometer reads accurately. To calibrate it they use the formula on the face plate. G is right that you don't want to tweak the spring. You want to spend your effort getting everything clean and moving easily.

There is a 3rd lube point where the speedo cable comes into the housing. You can get to it without taking anything apart.

I did quite a bit of research on this a while back. There is a guy from England that had a pretty good site and he recommended synthetic oil (bike chain, I think) because it does not thicken up like petro-oils - no volatiles to evaporate.

I hope this helps you.

[ian choplin]

Thanks a lot Conbs. It is not back together, so I'll look at it later this week. I did put some very light oil where the cable attaches, nowhere else.
It appears to work a little smoother each time I spin it, but occasionally the needle will bounce once or twice before it settles down. Maybe your recommendations will solve this.
I'll post back with results.
Thanks
Ian

[mike1969]

Just wanted to add a little info on the subject.
I've repaired 8 or 9 Dream speedos. When I tested them I used my Makita 18v drill. At full speed on the drill the speedo would register 30 to 35 mph. The return bounce of the needle is normal. When the speedo is installed it won't bounce.

[G-Man]

Mike

Sounds like your drill runs about 1000 - 1100 rpm. The Calibration for these is 2240 or 2250 rpm at 60mph.

G

[conbs]

Just wanted to add a little info on the subject.
I've repaired 8 or 9 Dream speedos. When I tested them I used my Makita 18v drill. At full speed on the drill the speedo would register 30 to 35 mph. The return bounce of the needle is normal. When the speedo is installed it won't bounce.

Mike,

You have more experience than I do on repairing Dream speedo's. I would agree that running the drill at full tilt and then stopping suddenly can produce the bounce. Your speedo cable will not stop suddenly while riding (unless you lock up the front brake). Under normal riding the revolutions of your speedo cable will wind down slowly with normal braking and there would be no bounce.

If you run the drill up to speed and slow it down gradually (as would happen when you are riding) you should not get the bounce. That test can be done before putting the speedo back together. Agree?

[mike1969]

Conbs, Hopefully we're talking about a very small bounce down the 5-10 mph level and not a 30 or 40 bounce.
After I did my first speedo and realized it was the drill causing the small bounce I ignore it. If the speedo climbs smoothly and comes back down smoothly it will be ok.
You also have to make sure the speedo doesn't climb to 60 or 70 mph when using a drill to run it. That would mean you are probably using the wrong lubricant.

[conbs]

Agreed.