The Knowledge - Velocette Owners Club

coming from (top end, barrel, bottom end, timing chest etc.). It can be quite revealing. I wouldn't advise
getting too close to the HT lead!
L # 6179 My Venom makes an irritating intermittent squeak while riding. Of course, as these
things go, I can't reproduce it in the garage. While poking my head around while riding, I think it may be
coming from the Lucas Dynamo. Does anyone know if the bearings in the Dynamo require periodic
lubrication, some other form of attention, or is my Dynamo on the way out?
# 6186 Ah, the Intermittent Squeak! Shortly after buying my first Velo, it seemed certain that a mouse
had taken up residence in old and crumbling foam inside the seat of the Venom, as every time I took
the bike out for a ride it squealed in terror, especially when I wound on the throttle. I even went so far
as to take the cover off the pan to release the hapless vermin, but the foam had crumbled honestly
without rodent help. Anyway, after putting the bike on the stand and running her up and down the rev
range, it was clear that the squeak was coming from the cylinder head. How had the mouse survived in
there? Removing the head and annealing the copper head gasket got rid of the mouse for good.
# 6193 I'll try additional diagnostics when out on my morning ride this weekend. I know it is an engine
generated noise, as pulling in the clutch, letting revs drop to idle at speed stops the squeaking. This is
still a very new bike (612 miles from new so far), and was built quite casually it seems in 1970, so
anything is possible. By the way, how does the head gasket potentially make this noise?
# 6194 Loose head hold down nuts allows the head to lift when hot, creates leakage past head gasket
# 6195 I had a similar problem and the beauty with singles is you can give the head a little lap against
the barrel. Problem solved, tightened me nuts and me head's not loose either.
# 6188 While your noise could of course be one of any number of things, it might be worth checking for
something mysterious which gave me a bit of grief lately on my own VM .. . symptom was a weird
screechy sort of noise (almost like that sick rattle that accompanies a partial nip-up of the piston). The
cupped dust cap over the lef tside front wheel bearing is meant to be a press-fit onto the narrow
shoulder of the collar/spacer that sits on the end of the bearing spacer around the axle. In my case it
had become slightly loose (dunno how) such that it could move enough to longer be aligned axially with
the axle ~ & consequently the inner edge of the cup could pick up on the face of the ali hub underneath
it, & it would start or try to spin despite the efforts of the axles clamping effect to stop it .. . . so hence
the horrible screeching noise as it argued with the two opposing faces/forces . .. The solution was to
dismantle the assy &, after pressing the cup back onto the (far too) narrow shoulder in carefully
squared alignment, a couple of spots of TIG have hopefully secured it permanently. BTW, the collar it
sits on was extra tight on the hub/bearing spacer so I relieved that fit slightly while all was apart.
L # 6301 Has anyone any idea why an engine that has a strong tick over, accelerates well with a
good handful and has a good top speed should always cut out when the throttle is opened a fraction off
the throttle stop? The carb is on a standard setting with a good plug and ignition.
# 6303 blocked idle jet?
# 6304 Sounds a little weak - is the slide worn?
# 6307 Try raising your needle one or two notches! douglas.
# 6308 Try a bigger pilot jet. If it wont start anymore then the pilot jet is too rich, go back one size and
that is the right size. Pick up should then be clean and responsive.
# 6311 Go back and review the AMAL tuning instructions and study the pictures. Throttle openings up
to 1/8 = pilot circuit throttle 1/8 to 1/4 = cut-away 1/2 - 3/4 = needle position 3/4 to full = main. If the bike
starts fine and idles well, the problem is the transition between the pilot system and the slide cut-away.
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