OzVMX Forum

Clubroom => Tech Talk => Topic started by: Mudnut on July 24, 2013, 08:26:20 pm

Title: Yamaha YZ / IT Front Hubs
Post by: Mudnut on July 24, 2013, 08:26:20 pm

Hi all 

Ive another question 

Does anybody know how to tell the difference between YZ 490 & IT 490 front brake hubs ? I need to re-spoke a wheel and been advised the hub & spoke sets are different on each model  . Before you ask , the wheel is not fitted to either a YZ or IT but a JBR . The bloke I brought it off many years back swapped out the original forks & front wheel to use the twin leading shoe brake of the  Yamaha . Ive a hunch its YZ , the inside of hub ( brake side  )  has 1K711 in the casing . I notice the brake plates & hubs are different due to owning both . How ever I have no idea which one  is which . It may be even YZ465 but unsure if that had a twin leading shoe front brake . Can some put me out my miserly

Cheers

Mudnut

Title: Re: Yamaha YZ / IT Front Hubs
Post by: tony27 on July 24, 2013, 08:44:52 pm

YZ465 is tls brake, anchor point on the forks is at 45deg whereas 490 is 90deg
It hub will have lugs/cutouts on the opposite side to the brake for the speedo drive, apart from that I don't think there's any real difference

Title: Re: Yamaha YZ / IT Front Hubs
Post by: Nathan S on July 24, 2013, 08:50:56 pm

The 1K7 hub was the universal IT/YZ hub from 1977 to 1982 (plus the IT400C which donated its prefix). There were a couple of different brake plates to go with this hub - the differences do not relate to the hub, obviously.
YZ-Ks got a dimensionally identical, but visually different hub. 23X prefix, IIRC.
YZ-Ls and IT200Ls got the Z-spokes.
Not sure abou which hub the IT-Ks and later IT250/490s got - educated guess says 1K7.

Simple answer is: 1K7 hub = spoke kit for (say) a 1980 YZ465G will be what you want.

Title: Re: Yamaha YZ / IT Front Hubs
Post by: Mudnut on July 24, 2013, 09:40:28 pm

Wow

Thanks for the quick replies , so to make 100% sure the hub is off a 1980 YZ465G , the TLS brake plate I need to use  has 3R500 in casting & the hole for one of the brake activator shaft  is approximately 30mm on the left of  the fork anchor point . The other hub 23X00 prefix the TLS has 5X600 in the casing and the brake activator shaft  hole is over 80mm on the left  the fork anchor point diagonally  .

I would attach a photo but that facility has been removed due to  limited disc space on server .

Mudnut     

Title: Re: Yamaha YZ / IT Front Hubs
Post by: tony27 on July 25, 2013, 08:33:08 am

You've got it correct as to which brake plate is which, all about where the tab on the forks are

Title: Re: Yamaha YZ / IT Front Hubs
Post by: Mudnut on July 25, 2013, 08:25:46 pm

Thanks for the answers , one last question . I can get a complete set of spokes for a YZ465H 1981 on ebay , is this the same hub use on the G 1980 model  or did Yamaha change the configuration that year .

Mudnut

Title: Re: Yamaha YZ / IT Front Hubs
Post by: Nathan S on July 25, 2013, 10:22:59 pm

Same hub was used on all YZ125/250/400/465/490 from 1977 to 1982. It was also used on IT175/260/400/425/465 from 1976 to 1982.
...among others.

If there's any difference in part numbers for spokes, its purely to do with butted vs non-butted spokes and gauge of spokes - they will all fit perfectly.

Title: Re: Yamaha YZ / IT Front Hubs
Post by: Mudnut on July 25, 2013, 11:10:30 pm

Thanks Nathan , if you are ever in WA look me up & I'll shout you a few beers

Mudnut