Author Topic: I'm going nuts!  (Read 1301 times)

0 Members and 1 Guest are viewing this topic.

Online Devondan

  • Yama-God
  • ******
  • Posts: 2397
I'm going nuts!
« on: March 01, 2012, 09:29:30 AM »
Ok I've fitted up the new aluminium swing arm to my 77 YZ250D, and its looking good.  I have found NOS collars and new chain pullers are on order, but I then I realised that I needed a new axle as the 77 one was now too short !! - that's now arrived - NOS .. nice!!  But it didn't come with a nut. 

Now the problem - the 77 nut fits but will only turn on about 4 or 5 turns before it locks up,   I borrowed the nut off the IT 400D I have and that fits fine?  To the eye the threads and nuts look the same size - both axles are 1.5 pitch, but the micrometer says the 77 YZ is 15.5mm and the IT/78 YZ is 15.75mm?  but the old one is very worn so I cant be sure. 

So were the axle nuts a special Yamaha size different between the 77 and 78 YZ or am I going nuts? - or has anyone got a spare 78 nut!!! 

The on line parts books don't help as they merge the 77 and 78, but my paper 77 YZ book lists the number as 90170-16177-00 and the IT 400D that fits is 90179-16007-00 

Dan
IT  400D - Trail riding
74 Montesa Cappra - Racing
YZ250 H - Racing
Norton ES2 500 trials
Norton 250 Jubilee - Road
Norton 350 Navigator (in boxes)
Norton 350 Single M50 (in boxes)

Offline Jasonit490

  • Yama-Hero
  • ****
  • Posts: 293
Re: I'm going nuts!
« Reply #1 on: March 02, 2012, 04:22:57 PM »
Sounds like you need to find someone with an M16x1.5mm tap to clean up the thread inside the nut, that should fix your problem. Failing that if the nut still wont fit, the axle thread may not have been finished properly during manufacture and may need a die run over it.

                                                                               Jason.

Online Devondan

  • Yama-God
  • ******
  • Posts: 2397
Re: I'm going nuts!
« Reply #2 on: March 05, 2012, 05:02:15 AM »
The IT nut wont fit on the YZ axle - it seems too small  ??? the thread doesnt even start.  If the thread wasnt cut properly then I wouldnt expect the nut to fit.  As it stands the YZ axle and nut whether deliberately or not is not M16 * 1.5  :-\  ???
IT  400D - Trail riding
74 Montesa Cappra - Racing
YZ250 H - Racing
Norton ES2 500 trials
Norton 250 Jubilee - Road
Norton 350 Navigator (in boxes)
Norton 350 Single M50 (in boxes)

Online Martin I Henry

  • MODERATOR
  • Yama-God
  • *****
  • Posts: 9886
  • Europe
    • Dave's Bikes
Re: I'm going nuts!
« Reply #3 on: March 05, 2012, 06:01:25 AM »
I think I have the taps and die for that size.

You could always ship the items to me for correction if you can't sort it locally.

Dave R.

Online Devondan

  • Yama-God
  • ******
  • Posts: 2397
Re: I'm going nuts!
« Reply #4 on: March 05, 2012, 10:03:17 AM »
Thanks Dave, but all I need is an IT 400 axle nut, Cos I've borrowed if for the YZ !!

Dan
IT  400D - Trail riding
74 Montesa Cappra - Racing
YZ250 H - Racing
Norton ES2 500 trials
Norton 250 Jubilee - Road
Norton 350 Navigator (in boxes)
Norton 350 Single M50 (in boxes)