Well karcraft have advised me that the selector forks for a 3 synchro box are NLA and the same goes for the synchro springs...

I am assuming here it's a 63-on 850 box, not the POS early one with Minor 1000 cone synchros instead of baulk rings... they make good landfill.
Synchro springs for the 3 synchro baulk ring box you should be able to use the same as a 4 synchro, which is p/no 22G2262.
If Kc has none, try elsewhere.
Heck they are only a spring, we do still have some springmakers in this country...
According to AC Dodd in the UK, they are rated at 4.5kg max load. Not hard to get made from a sample...

3-4 selector forks are the same for 3 synchro and 4 synchro. Kc has them listed in current catalog.
1-2 selector fork 3 synchro is p/no 22A611, if Kc has none look elsewhere.

Some people in UK just squeeze these forks in a vice and re-use them, I think it's dodgy engineering as they are cast bronze (brittle) but there ya go.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Ok last question
How bad is it to reuse the gears if the dog teeth are rounded off?
Seeing as they will be extremely hard to find...

It will still work, as long as the dogs are not worn away badly.

One other IMPORTANT thing with a 3 synchro- carefully inspect the 1st gear teeth on both the cluster and the sliding outer ring. They tend to chip, or wear at an angle. The latter can cause jumping out of gear.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Sorry guys I have another round of questions

Quoting Dr Mini from this old thread;


Does this mean that if I have the later B form gears then just by putting in a cooper S layshaft I will then have a cooper S ratio box?

Thanks all for your help...
Cheers,
Alex

No it doesn't. 2nd gear IS the same, but 3rd gear isn't, neither is the 1st motion shaft, or the cluster gear (laygear).

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

you'd also need the right casing that had clearance for the S crank

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did I tell you that I won a trophy?

Only if you want a 1275... he just wants the gearing.
Nothing is impossible, I put a 1275 on an early 850 case once. Araldite and masking tape came to the rescue.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

that kills that idea i did think there would be more to it...
oh well it sounded good for a while
Cheers,
Alex