The Knowledge - Velocette Owners Club

L #650 Please tell me the parts number of the gear box end cover ball bearing for prefix 5.
#651 I am not familiar with all of the various gearbox serial numbers and their potential
similarities/differences. I can tell you that this bearing in my '50 MAC is a FAG LS5. Readily available,
at least here in the States.
L #681 Could you please suggest any remedies for an oil leak from the kick-start ratchet box, it
appears to be coming from the shaft. Is there any way of fixing it apart from buying a new box?
#682 Try here www.velocetteowners.com/qanda/gb008.htm
#683 I used a 19-27-4 single lip seal obtained from Bearing Services Ltd., fitted into a 4 mm deep
recess carefully bored in the outer face of the kickstart housing. The shaft was carefully deburred and
its diameter cleaned (if it's pitted or damaged the seal will not last long) and eased through the seal lip
so as not to damage it with the flat for the cotter pin. The lever was fitted as normal, being careful that it
didn't slide back through the seal during assembly, and the whole assembly then fitted back into the
end cover as per the manual, but with a thin smear of Three-Bond silicon sealant on the mating face to
seal it. This part of my machine has been totally oil tight ever since.
#685 There are people who will do an exchange or conversion with an O ring seal fitted to stop the oil
loss. Colin East on 01522-810029 does, I'm sure there are others too
#686 Some years ago, I tried to cure such oil leaks and followed the advise found in FT Hints and Tips.
So I get the housing machined to fit an O-ring. This proved to be an improvement for a while, but
seepage came back, although less than before, as 0-rings are not designed to cope with repeated
rotations, and they wear. Especially if there is some wear in the assembly. I'm now considering to fit an
oil seal instead.
#694 A quick remedy to ameliorate the oil weep from the kickstart housing without recourse to
machining it, is to epoxy-resin a thin oil seal 1x3/4x1/8 imperial obtainable from a good bearing stockist
for maybe £2.00,to the outside of the housing cover over the kickstart shaft. This may sound a bit of a
bodge but it does work without interfering with the kickstarter engagement.
L #1086 Have some of you experienced another way to secure the sleeve gear bearing retaining
nut than butchering the g/b shell, each time at the same places, which I hate to do ? Is Loctite safe
enough ?
#1088 I've a very worn thread on my gearbox plus a worn sleeve gear bearing nut on my Venom I've
used Loctite but a retainer not a threadlock type. With normal threadlock I've had a problem, but with a
high strength retainer I've experienced no problems, though I must admit my threads are very worn. I
might also add I've had no difficulty in unscrewing the nut after I've used the retainer.
L #1969 After my 500 racer jumped out of 3rd gear several times at the last race meeting, I have
the gearbox apart. (And the road venom's gearbox for comparison) It runs a tt top gear and std 1st
gear. 1) The tt top gear with the sleeve-gear dogs looking very sorry. Does anyone out there have one
available ? 2) Any opinions on using a std sleeve gear plus tt 1st gear ?
#1974 You can use any sets of gears from a heavyweight box provided the total sum of the mating
gears on the main shaft and lay shaft add up to 44. There was an interesting article published by Bruce
McNair in Fishtail some years ago, which thoroughly analyzed combinations of using Prefix 12, 12R
and 14 ratios. Unfortunately I cannot tell you which edition of Fishtail it was published in. If you get
desperate I will scan the article and send it to you. You can therefore play with gears to ensure that the
engine stays within its power band for any particular combinations of gears. John Jennings from
Australia also developed a spreadsheet that calculates RPM and speed in gears. If you want I'll check
with John to see if he minds me sharing the spreadsheet.
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