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Collets and .... collets

Posted: Sat Mar 21, 2020 11:06 am
by AyJayBee
I have finally got round to starting to rebuild a 1961G80, bought as a project about 15 years ago. I stripped the bike and stored items 'safely', but the ravages of time and other distractions - including other bikes - are taxing my memory … 'now where did I put ….' or 'did that go that way round?' The latest stumbling block found me trying to rebuild the head - I know, hairspring valves can be a swine to fit, but this took the biscuit ….. having ground in the valves, I started to fit the inlet. I have one of the semi circular spring compressors which was duly fitted and I dropped in the first collet, followed by the second …. bit of a fiddle, but when I released the pressure on the springs the collets would not fall into place. Several hours - yes, HOURS! - found me still struggling with the first valve, until my son returned from work. He came to see how I was getting on, and his keener eyesight spotted a slight problem - the two collets were different profiles, and would not fit together. On checking I found there were 2 different pairs, one for the inlet and one for the exhaust, as the valve stems were different sizes …. Is that normal? Having matched the collets to the collars - also different! - twenty minutes later found everything sorted, well for the moment anyway, but watch this space! Tony.

Re: Collets and .... collets

Posted: Sat Mar 21, 2020 1:41 pm
by Rob Harknett
not got a 61 bike, but never found differences as you have found, on bikes I have got .

Re: Collets and .... collets

Posted: Sat Mar 21, 2020 3:03 pm
by 1608
As long as each valve stem is the correct fit in its guide ( don't confuse the i/l with exh valve) thats all that matters. The wasted bit of the v/stem may vary slightly for each set of collets.

Re: Collets and .... collets

Posted: Sat Mar 21, 2020 5:17 pm
by SPRIDDLER
1608 wrote: The wasted bit of the v/stem may vary slightly for each set of collets.
Agreed. And perhaps after all these years it may have received a universal pattern valve (and collets) which will not necessarily be the same design as an AMC factory valve.

Re: Collets and .... collets

Posted: Sat Mar 21, 2020 5:36 pm
by ajsph
in 1960 the 500 single got a new type of exhaust valve (026029) and collets
Poul

Re: Collets and .... collets

Posted: Sun Mar 22, 2020 3:30 pm
by AyJayBee
Thanks for your responses - there is a noticeable difference between the assembled collets to suit presumably the valve stem diameter. a 'pair' made up from the two different sets would not locate in the stem recess. But at least the problem was sorted