A7 gearbox woes

[BSA500]

Just taken the A7 for its MOT and it passed whopee. Now the woe. Tried to leave the station and the box is stuck in gear it took me 5 mins to get neutral so stuck it into second and rode home unable to change. Ok thought I quick removal of outer case and repair whatever was wrong. Parked up on the sidestand and the box spat out all of its oil I mean ALL bar a trimble full. Why?? I have not opened the box up and it was changing gear just fine before I left for the MOT. Looks like the seal has gone so I may just get out the spare box shell and replace the bearing and seal and swop over sound like a plan? have I missed anything?
Andy

[1660bob]

Hi Andy, take a look underneath first.If it has spewed almost all its oil, the sprocket seal may not be the culprit as it is too high.Given that the gearchange has suddenly gone west, some sort of mechanical issue has taken place (obviously)and my first thought goes to the detent plunger under the box at the front-has it unscrewed? Only other routes out of the box for the oil are, as far as the main casing is concerned, drain plug- no effect on gearchange as such(until the box seizes and throws you off the bike!!!) or the layshaft bush-has it disintegrated causing the shaft to drop and jam the selector forks? All a bit grim but needs proper investigation for safety. HTH, keep us posted, Bob.

[trevinoz]

Andy,
          I agree with Bob. It sounds like the detent has gone missing. That would explain the gear change problem and oil going missing.
Trev.

[BSA500]

Ran out and checked and the indent plunger is fine and dry. The oil does seem to be coming from the sprocket area and if you don't remember this bike was stolen and ridden around the woods for a couple of days. Maybe a selector and seal were damaged by less than careful gear changes by the little **%"!. But you are right it has to come apart so I may as well replace the bearing and seal, its been a while since I last did them.
Andy

[wilko]

Doesn't really explain the no changing though?

[BSA500]

Your right it doesn't but I shall start dismantelling this morning so I sould have a better idea later today and report back.
Andy

[BSA500]

Found the problem the grub screw from the selector rod has gone allowing the rod to work its self out and foul the gearchange pawl thingy. It was so well wedged I had to drive it out with a drift. Still means I have to get a new one and a seal as that seems buggered. If the bearing seems ok I will not take out the case saving me some grief.
Andy

[1660bob]

Sounds like a result Andy- i take it the oil was exiting via the hole vacated by the rod. Hopefully little or no damage then. Bit of loctite on the grubscrew will stop a recurrence-(nutlock, not the super powerful grade!).Make sure the slot in the grubscrew is not chewed up otherwise future dissasembly could be a PITA (Draganfly have new ones listed 67-3117),Best of luck, Bob.

[BSA500]

Yep Bob could be the reason I lost all the oil but I still will clean it all up and replace the seal. I am getting the bits from Draganfly.
Andy

[BSA500]

Just got the box apart and the grub screw is still there, one less expense. Looks like alot of the oil escaped via the bearing seal and the rest pass the selector rod hole. Lots of threadlock this time . New seal has been ordered.
Andy