Speedo drive AGAIN

[gaz_powell]

make sure it runs smooth backwards and forwards - all best done before its back in the forks then unfortunately its a baptism by fire !!!

good luck

[vRSG60]

Spent an hour and a half sorting this out. It spins freely and an allen key rotates when put tin the end of the worm.
But I'm not sure mine will ever work properly. I put grease on the worm and assembly the backplate back on the hub, spin the backplate quite a few times and disassemble. The grease has hardly marked the gear drive and only at the very top, the grease hasn't gone very far down the teeth, indicating to me that the gear and worm are only contacting for a minimal distance at the top of the teeth. Hardly any mesh between the two.

Maybe this is why so many people have problems. It could be the outer diameter of the gear and worm is too small. Meaning there isn't enough contact between the two to provide a good, positive, lasting drive.

[vRSG60]

Test ride went well. A mile down the road no speedo at all.

Not a clue what to do now.

Can somebody post a picture of the worm assembled in the backplate showing the correct position or how much play there is. Mine has a LOT 3mm or so.

When the wheel is turning the force is to push the worm further into the backplate and I suspect over 40 years mine has worn the casting away and now the worn has minimal contact with the gear. I've tried washers but still no joy.

[vRSG60]

Should there be as much play in the worm drive as I have. Indicated by yellow pencil.

[vRSG60]

Well I've bought a new backplate but the amount of play in the speedo drive worm is just the same so I don't hold out much hope things will eventually work. Awaiting my 4th new speedo drive in a month now before it all goes back together.

[gaz_powell]

in the photo the worm isn't pushed fully home the tip should not seen when the assembly is tightened up

or is that just to show the play ?

[vRSG60]

Just to show the play Gaz, the action of the worm against the gear pushes it home in the bore.

[gaz_powell]

I have seen sets with metal worm and a plastic ring - which seems strange to me as the worm should be the sacrificial part like a vespa however the ring looks wider - might be worth a try might give more contact between the two parts once assembled

http://www.ebay.co.uk/itm/LAMBRETTA-SPE ... 43b2b542f5

or

scootRS new all plastic

http://scootrs.com/moreinfo.cfm?Product_ID=2429

keep us updated

[dapper]

Should there be as much play in the worm drive as I have. Indicated by yellow pencil.

I refer you back to my previous post where I stated that I put a 6mm SS washer on the worm drive first before installing it, to take up some of the slack you are indicating, so centralising the worm drive. I tried putting one on the other end of the worm drive, but it was a tad too thick and stiffened up the mechanism, so I wore away my fingertips making the second washer thinner until all was free to move smoothly. I've just got back from a rally in France (done about 450 miles) and mine is still workin fine, although it still does that thing where it's smooth up to 50MPH and then has a fit after that

[vRSG60]

Thanks, I've tried washers of various combinations in different places. I'll assemble it all tonight and take it from there.