Three Speed Gearbox | Scotts Owners Club

This topic has 2 replies, 2 voices, and was last updated 9 years, 2 months ago by fredvincent.

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15th July 2014 at 4:49 pm #3756

fredvincent
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Finally finding time to strip my 47 Flyer gearbox which, in a previous thread I mentioned, the gearchange does not move, which appears to be down to whatever lubricant was left in the box while it was standing for 40 years. The gears are covered in a soft varnish which presumably has stopped the sliding gear from moving and hence the selector fork. I have tried heating the end cover to release the right hand mainshaft bearing, but without force, does not want to move very far. Before I remove the box from the bike, I want to release the selector fork spindle. Once I have tracked down a ‘drag link socket’ or ground down a chisel with hex shaft, I will attempt to turn the 1” dia. screw head anti-clockwise if that is correct. I can only find cross-sectional drawings of Super 3-speed boxes, so am assuming that the spindle has a right hand thread and a square on the end at the gear change lever end with thread (front of box). Am I on the right track? I do not want to start forcing the screw head any more, as I have tried impact drivers and all sorts and just damaged the slot.

My other question is on the gearbox final drive chain sprocket – mine has a 19 tooth, but am not sure whether this is standard for a solo?

Thanks in advance.

15th July 2014 at 5:40 pm #12495

dave bushell
Participant

Final drive sprocket for a solo is 21 teeth.
The selector fork has a “V” cut into it and the selector arm has a corresponding male “V” that engages with the selector arm. On the rear wheel side is a plain bush and the whole assembly is clamped together by the bolt with the slotted head. On one of my gearboxes, the slotted bolt has been replaced by a normal hex bolt and a washer to retain the plain steel bush. The thread is right hand.
Dave

15th July 2014 at 7:55 pm #12496

fredvincent
Participant

Thanks Dave. I now realise that the only thread on the spindle is at the end holding the gearchange arm and that the spindle is free to turn in the bush with endfloat controlled by a thackery washer between the arm and the gearbox. In other words, the spindle should be free to turn including the slotted screw head when the gearchange lever is moved. Therefore, I should be able to take the lever off after the nut is removed and gently tap the shaft out. There I was thinking the shaft screwed into the gearbox!
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