Could someone please point out the finer points of identifying a 1969 inner timing cover part number 70-9482.
My '69 Lightning came as a basket case without the inner or outer covers.
I read somewhere that there are six different types of these covers from start to finish.
Studying my extensive collection of parts catalogues ( I think I've got eleven now) only three years ('67, '68, and '69) have the dipstick hole in the cover AND the early type clutch actuating arm.
The '67 and '68 have the same part number (68-868)
The 1969 cover is apparently unique to that year.
So that narrows it down to two types which are easily identifiable.
So what is the difference between the '67/'68 cover and the '69 item ?
I'm not seeing any obvious difference just looking at the parts books
Wasn't there a change in idler pinion and the bushes?
Greetz alex
Hi,
The earlier cover part number is for the "inner cover". The 1969 part number is for "inner cover with fixed fittings". Possibly the 1969 cover was partly assembled.
Best wishes...
Quote from: Gup holland on 23 Apr, 2023, 16:29
Wasn't there a change in idler pinion and the bushes?
Greetz alex
I've just checked that and I think you may well be right.
The '68 reprint catalogue I've got shows one flanged bush fitted to the crankcase, but no bush at all for the inner timing cover.
Looks like someone at BSA made a boo-boo on that one.
The one bush shown is 68-28, with 68-978 for the idler pinion.
'69 and '70 shows two straight non-flanged bushes 70-9809 and 70-9104 for the idler pinion.
I'm assuming that the crankcase and the timing cover are machined differently for the new type bushes,
So today I have learned something else about my A65.
Many thanks
Maybe for your information or others, i have 63 cases and a late inner cover part no: 71-1047 ( Can not date it, I think 70).
In the case there is a flanged bush, in the inner cover a plain bush. The pinion is from the late type.
It's mixed but fits. The whole engine is from several parts, work of a former owner, do not know the history.
It has the 3 ball clutch lever and dipstick.
On the crank side there are 3 numbers, they should match with the case numbers. The 2 bushes has been line reamed. I renewed these bushes so it have to be line reamed again.
Took some pictures of the cover and the pinion.
Greetz alex
Many thanks Alex.
That's one of the things I love about the old industry British bikes.
If you have engineering skills you can mix, match, and modify to your hearts content
67 cases should not have the gearbox dipstick within it as that was part of the crank case, however 68 should, parts books often have information from earlier years as the books were printed prior to the bikes completing production.
68 bushes were the top hat type for the idler gear and 69 were not which has already been pointed out. I believe some 69 cases had the cross hatch webbing which you sometimes see on them as this was an attempt to reduce the harmonic noise to meet Mira specifications - it didn't seem to work as later bikes carried on without them.
In reality, providing the inner timing cover has the two locating dowel provisions then any of the cases will fit without a problem. Just ensure there is some endfloat for the idler gear and that the idler gear and its pinion is the correct your your inner timing case/crank case setup. And where possible, line ream the bushes, from memory this is 11/16"
My own 68' for example has a 71' inner timing cover fitted and I modified it to accept the correct clutch mechanism for 68'. To look at you would never know.
Hi,
The cross hatching inner cover should not be used on 1969 bike, it hasn't got the solid dowel holes or oil dip stick cast into it.
Best wishes...
Quote from: Bess on 08 May, 2023, 11:47
Hi,
The cross hatching inner cover should not be used on 1969 bike, it hasn't got the solid dowel holes or oil dip stick cast into it.
Best wishes...
Thanks for the clarification on that one Bess, I'll amend that from my last post if it will let me. (Which it won't as it must be time limited)