I stripped down my Dommi AMC gearbox as I couldn`t trust the person who apparently `rebuilt it ` and true to form immediately found a broken Kickstart return spring ! On continuing I noticed some worn `Dogs` on Main shaft 2nd and 3rd gear cogs. (See pics Attached ) . Is it advisable to replace these two gears due to the wear ? I have no idea if the box worked as I am still building the bike. It appears my gearbox is an `Early` one as I read they changed some gears after a certain year. I have found both gears for sale but only one supplier (Andover Norton) hold them in stock. RGM advertise them at a more reasonable price but don`t have them in stock ( Sorry Ashley ! ) . There seems to be a shortage of these Main shaft gears as Layshaft gears seem to be so much easier to get . Am I right ? Does anyone else notice this ?
ALSO the gear change Quadrant retaining bolt simply will not undo. It simply rotates either way and looks like it is `swaged` over on the inside. Anyone seen this before ? Please see photo Attachments and thanks up front for any advice .
Gear wise i would replace…
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Thanks , No offence to AN as…
Thanks , No offence to AN as they have helped me with loads since trying to get this dommi together . The quadrant has been held from moving but the retaining bolt is just spinning and not coming out .
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The quadrant that you've…
The quadrant that you've depicted fits into the main shell through a bronze bush in which it can rotate. A seal and a short hexagon-headed screw complete the installation. To remove the quadrant usually requires the screws removal and a stiff press pushing the quadrant into the empty shell. If the screw's thread is stripped you should be able to hacksaw the head off and then with the quadrant removed the rest of the screw drilled out and re-tapped. (1/4 inch X 26 tpi BSCycle thread - probably 3/4 inch long _ same length as the camplate securing screw). It could be 5/16 inch screw with a reduced hex, hexagon head. Good luck, Howard
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Having removed the cam plate…
Having removed the cam plate I can see when I turn the bolt that the bit that looks swaged over is spinning too. I have no way of holding this to enable the removal of the Bolt it seems other than trying your suggestion .
Thanks , Wayne .
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If you have a large easyout…
If you have a large easyout try that from the gearbox side, failing that grind the head of the bolt off (the washer should prevent any inadvertant grinding of the gearbox shell) when the quadrant is removed from the shell you might find that you can unscrew the rest of the bolt with your fingers.
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Thanks Peter , I will be…
Thanks Peter , I will be attempting to do the job today .
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What a great bit of advice ,…
What a great bit of advice , the large Easy out worked brilliantly . Got the bolt out without any grinding too ! I`m amazed that the only thing holding it from `spinning ` is the splayed end which I tightened up after getting the quadrant out by splaying it out again with a large ball bearing and the ball end of a hammer. I wont be over tightening the bolt when I reassemble the box and have drilled it to enable wire locking. Another job overcome thanks to you , Cheers .
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Just to answer...
... your original question, those dogs have had it. They won't stay engaged and you'll get jumping out of gear. It seems you're wise not to have trusted the person who rebuilt it.
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Gear wise i would replace those pinions that have the worn dogs otherwise you stand a good chance it will jump out of gear. You can try secondhand but it will always be a lottery as to condition.
What do you call a 'reasonable' price? Go to Nova Racing transmissions and see how much it costs to manufacture gear sets and pinions. ANs price is very reasonable and more importantly available.
Regarding the quadrant. refit the inner cover and prevent the quadrant from turning by using a bar in the quadrant aperture. Then undo the bolt