Mk 3 Gearbox

Previously Katherine Scott wrote:

Hi Mike

A couple of things to check are both dowel pins in the primary drive case? to help with the alignment of inner and outer cases.

Have you replaced the bushes in the primary cover ? I have known them to be a little tight when replaced. you may need to ease them.

Best regards

Katherine Scott

Katherine thanks. Both dowel pins are in. Will check bushes

Previously richard_payne wrote:

Perhaps a daft question, but are you using the factory manual, and have you placed the large OD washer in the correct place ? If you look at the detail drawing, this washer which is described as the 'spring retaining washer' is placed between pawl spring and pawl arm but the exploded diagrams all show it on the other side, between arm and outer cover to retain the return spring.

The OE washers were very thin shim steel washers - anything resembling a mild steel large OD repair washer will be too thick.

In terms of camplate timing, once again, following the factory drawing and trying to align the quadrant as they have it will mean that it contacts the aperture in the inner cover.

It's quite possible to remove everything except sleeve gear and mainshaft without disturbing primary transmission, but in fact you don't need to go that far. It's a fiddle on the Mk3 though as the crossover shaft and the starter motor get in the way. You'll need to slacken off the camplate bolt and ease it forwards, then carefully move the quadrant by one tooth before moving the plate back in again.

Richard many thanks. The camplate timing is out for sure, and yes I probably did follow the workshop manual on re-assembly. Have you got the part number for the 'spring retaining washer' and 'pawl spring' so I can locate it in the parts book and help me to clarify.

Previously richard_payne wrote:

04 0135 and 04 0038.

The Andover Norton on-line shop is the easiest way to look at these parts in detail.

Unfortunately, this message board doesn't let me link as I use firefox or I would do that.

Richard thanks again. Yes I see the parts clearly on the AN site which is exactly the same as the parts catalogue I have here for the Mk3 which is what I would have followed for sure. So are you saying the AN exploded diagram is wrong with regards to the position of the spring retaining washer?

Previously christopher_winsby wrote:

Have you looked at Old Brits Norton web site Technical part? They cover gearbox rebuilds and other useful stuff.

Chris thanks. I knew they had technical advice about it and did look through it for prompts but obviously I didn't follow the advice close enough.

regards

Previously christopher_winsby wrote:

The back of the innerchaincase is held by a stud with hex bar in the middle secured to the gearbox cradle one end and clamping the chaincase between two nuts the stud is item 23 on Andover Norton web site ( chain case section). It might be worth checking that the stud is adjusted right and not pulling the chaincase out.

Thanks again Chris. I hadn't thought of that one. I do remember tightening it up on the rebuild but not checking it after the primaryside was re assembledso will check it for sure.

Previously dave_taylor wrote:

Previously mike_steer wrote:

Just completed total rebuild on my Mk 3. With jangling nerves started it up and we embarked on itsmaiden 'road trails'. Really pleased with the ride. Total contrast to BSA and Triumph TriplesI am used too.

Main problems are;

• Firstly, Gear shift is stiff on the change. Will select gears but not return to starting position. I have to touch it back with foot each time. Took primary cover off and activated/twisted change over rod and there was plenty of spring to return the rod back to its starting position.It appears that once I re-close the primary case it tightens again. Have changed the large outer washer and the 'E' clip that retains the gear shift shaft. It is better, the new washer is thinner than the previous one, but I'm not convinced its correct.The only thing I can think of is to remove some of the washer face to make it thinner. Is there anything else I should be looking at?
• Secondly, First gear won't engage. I've not put it back together correctly. In simple terms I need to take the gear box apart and adjust the teeth on the quadrant and change mechanism one way or another so all gears engage. Will I need to remove the primary side thoughto do this. Was hoping to remove enough of the gearbox innards with just taking the outer and inner casings off?

Could the problem be with the primary cover? I know that if the bike has been dropped on the near side the footrest can hit and delve in the primary cover ever so slightly. The through shaft is then nipped up between the primary cover and gearbox internals giving similar symptoms that you are experiencing.

Slacken off the primary cover and see if there is an improvement.

Dave

Dave many thanks for your input. I am going through the gear box at present. Outer cover off. The thing is though all the gears are selecting ok when I rotate the back wheel and lever the quadrant up and down. I'm going to put everything back now taking into consideration all the suggestions the fantastic members on here have offered up. Fingers crossed

Many thanks to those members who replied to my original post, Katherine, Richard, Christopher, Dave. Took on the advice and checked out everything. Strangely, when I took the outer gearbox cover off all the gears selected fine up and down the box. After scratching head several times the only other adjustment I had made was to screw out the neutral light switch in the gearbox casing. I concluded that the switch body was screwed in too far and the 'neutral dome' on the face of the camplate was stopping up against the threaded brass stem so I couldn't get full movement to engage first gear. There was me prepared to pull the gearbox apart. All fixed now.

Again thanks