Topic: Rotor/Rear Sprocket Lock Nuts

[stwinton]

Is there any alternative to using the old school bent washer trick to lock the rotor nuts and rear sprocket nuts? The nuts are thinner than usual so I suspect that nylon lock nuts won't fit. Or is there another reason why we have to stick with original spec?
Thanks!
PS...the CB550 is in its component parts...I await deliver of the long nosed C ring pliers from Dime City Motorcycles. 3 weeks to Australia! Might have to re-think this vendor...

[raymond10078]

Later bikes used flange nuts - with no locking mechanism - that's what I went with on my 750.

My son's 450 has similar nuts.

I didn't catch the year of your bike, but I'd bet you have 10mm studs.  If so, this should work:  90308-382-670 or 94050-10080.

[stwinton]

hi kandrtech
Thanks for the heads up about flange nuts. I have seen them but didn't know their name.
My little beast is a 1974 frame 75 engine. Its in pieces right now...down to its component parts.
The last bike I did (Bultaco 1971 Sherpa T) I replaced every nut, both and washer with new. Including nylon lock nuts AND star washers. But I never used a single flange nut...another bit of knowledge. Thanks!

[TonUp_UK]

I have a CB550F2 1977. Just doing a bit of restoration and I have ordered a set of M10 flange nuts to replace the original nuts / ali plate setup.
Problem is - the new M10 flange nuts will not fit, looks like there is a special thread on the studs? I have measured the studs and they are 10mm?
Any ideas?

[raymond10078]

I suspect that they are fine threads...not "special".  I see three nuts sizes/threads: M10-1.0, M10-1.25, and M10-1.50.  The 1.0 is a fine thread, and the 1.50 is a course thread.

[TonUp_UK]

So, M10 x 1.25 or M10 x 1 . Which is the correct one for my CB550?

[raymond10078]

Best way is to measure.

Count ten threads and measure in mm, then divide by ten.

[754]

Get a pitch guage or measure, most bolt sizes have several pitches.

[Airborne 82nd]

Something like this mine came with tap & die set.
http://www.grainger.com/product/VERMONT-AMERICAN-Screw-Pitch-Gauge-2NXA5?s_pp=false

[TonUp_UK]

I bought these off ebay "M10 x 1.25 Smooth Faced Locking Flange Nuts" and they are spot on.

[Tugboat]

M10x1.25 is Honda standard

[raymond10078]

Standard for what, exactly?  750 rear sprocket nuts are M12.  I forget what I ended up getting - possibly M12x1.25.

[calj737]

1.25 thread pitch for M10 bolts and nuts, plus caliper blind holes, etc...

[raymond10078]

Thanks.  Good to know.