MRC Forum- brought to you by www.morini-riders-club.com Member: g7AW3f

For my unfinished Kanguro I need the nut that goes on the end of the camshaft on the left to hold the pickup rotor while also driving the tacho. The various parts manuals I have are all for the electronic tacho models so I don't even have a part number. If you've got a suitable nut that'd be brilliant, and the part number would also be useful so I can search for one online.
Thank you
Julian

Ok, for the electric tacho variant it is an M7 nyloc nut.
On my 1978 bikes the same nut is used to secure the rear brake torque arm to the frame and the clutch lever mount to the handlebar (if yours still is, then this nut/bolt can be changed to 6mm items and you can use that nut).
Of course, you shouldn't reuse a nyloc, but...
New nyloc M7 nuts are available from Dave Middleton but you might need deep pockets. See: https://www.stainlessmiddleton.co.uk/

Hi Julian, the tacho drive nut part number is 46.03.33, sorry I don't have one to spare but Mdina have them.

I wonder wether it is the same metric m7 nut as for the brake levers etc. Surely it will be a "fine thread"!

Underneath you need the special washer as usual. But don´t forget to ad also a spring washer! If not, the nut will en up like the one from the foto. The end of the cam will open the square hole for the speedo cable.
This one probably was used without the special washer. But I also have seen them a bit less destroyed when the special washer was used without the additional spring washer.

norbert

Another vote for using the correct washer. A jangling about pickup rotor soon leads to no sparks - BTDTGTTS.
46.03.33 is the same as on the 250 V which all have mechanical tacho drive.

Thank you all for your prompt suggestions, I've found the correct nut 46.03.33 on mdina's web shop. I'll buy some M7 washers and spring washers separately. Then I'll coax see how accurate the rev counter counts

julianharty wrote:Thank you all for your prompt suggestions, I've found the correct nut 46.03.33 on mdina's web shop. I'll buy some M7 washers and spring washers separately. Then I'll coax see how accurate the rev counter counts

The washers referred to are special ones (not the spring washer obvs) It's flat but with a recess on the back. I may have some of those as well as the nuts but it will be a day or two before I can check.
A regular flat washer won't do the trick!

Steve,
If you have the relevant washers that'd be really helpful. Thank you.

Meanwhile, does anyone know the part numbers for these special washers please? I'm building up a shopping list for the various parts currently.

Julian

According to the 250 V parts list - 47.07.03 6 x 13mm - special 'dished' washer as Steve pointed out.

Hi Julian, the dished washer is the same as on most later ignition rotors and there is a larger sleeve/washer on the tacho drives that have an additional support bearing.
Both types use the same drive nut and spring washer.