Author Topic: m.k gearbox  (Read 448 times)

0 Members and 1 Guest are viewing this topic.

Offline phil1

  • Full Member
  • **
  • Join Date: Mar 2017
  • Posts: 59
  • Location: Aylesbury
m.k gearbox
« on: 11 Jun 2021 at 08:30 »
Hi my friend Bob has recently acquired a mk.v is there a quick answer to no fourth gear? just feels it won't quite drop in, unfortunately he has persisted riding and the result is no gears at all!, so after removing gearbox selector cover the worst was clearly visible one selector had broken in half, any thoughts appreciated.  Phil.

Offline LENBOY

  • Member
  • *
  • Join Date: Dec 2013
  • Posts: 8
  • Location: united kingdom
Re: m.k gearbox
« Reply #1 on: 13 Jun 2021 at 10:08 »
Hi Phil
I was hoping one of our engineer members would have answered this for you as my engineering knowledge is next to nil, but here goes. I am assuming it is one of the two gear selecta forks that have broken which I have not heard of before, if that is the case the gearbox will have to be separated from the back of the engine to remove the shaft they pivot on which is drawn out from inside the gearbox bell housing and is retained by an aluminium slotted plug. I hope this helps, but stand to be shot down if wrong. Best Wishes,Len.

Offline eddie

  • Master Member
  • ****
  • Join Date: Mar 2006
  • Posts: 1726
  • Location: Hampshire, UK
Re: m.k gearbox
« Reply #2 on: 13 Jun 2021 at 11:33 »
After a life of 65+ years, the majority of gear selectors have needed some remedial work. Any building up of worn forks or pins has to be done professionally, as overheating or sudden cooling can render the selectors glass hard (and equally as fragile!). One broken selector may result in loosing one or two gears - but not all of them. If all gears are missing, I would start by looking at the input shaft or flywheel coupling. Following that, work your way through the box to check for other damage - with a broken selector, the 'box may have locked up due to 2 gears being selected at the same time - the broken selector leaving one gear engaged while the other selector engaged another gear - possibly shearing a key or splitting a gear pinnion.

Regards,
               Eddie.

Offline phil1

  • Full Member
  • **
  • Join Date: Mar 2017
  • Posts: 59
  • Location: Aylesbury
Re: m.k gearbox
« Reply #3 on: 13 Jun 2021 at 17:07 »
Hi Eddie
            Thanks for the info, gearbox is now off and looking in the bellhousing some evidence of previous dismantle. Cheers Phil.