Britbike forum Forums Thread Like Summary - And I thought I was a bodger

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I do think it reduced the vibration a bit. It’s a Triton and the usual recommendation is to give it a bigger balance factor than a Triumph.

I laid the bike on its side and attacked the flywheel adjacent to the big ends, enlarging a hole that was there already.

Just a hand-held drill and paper towels packed into the gaps, to stop the swarf getting into the crankcase. It’s easy!

It seems like a slight improvement. I haven’t taken any more metal out of the flywheel since: there’s such a thing as quitting while you’re ahead.

Quite a well known and successful racer here around the 90's used to set his motors up that way.
Mostly triumphs.

Weslake cranks had a trim-able heavy metal plug that could be removed and refitted.

There is absolutely nothing wrong with these procedures, balancing a single or twin cylinder
vertical motor of any type is hit and miss/stab in the dark as far as flywheel weight is concerned.
Blokes like Magnetoman could spend 20 years calculating what he thinks is right to find that
in the real world the bike had intolerable vibes at xxxx RPM.

Yes, it’s trial and error. Anyone can see how, in many individual cases, it can be better than the prescriptive factory advice.

'Cos the sludge tube plug is the timing side on the crank................

I like it, its the sort of thing i would try, how did it work out for you TT.?

Bodge? I thought that was how these things were assembled: measure, disassemble, more shims, measure, repeat.

Don't let Magnetoman see this.


It does emphasise the points that these bikes weren't considered to be anything special when the were new(er), and that anything can have happened to them* in the intervening decades.


[*] and it usually wasn't something good

I think thats something sent out by Hap and not the factory,

Its missing the part after "... a screw driver slot cut in the top edge is centerpunched to prevent backing out and thus the wheel is returned to its original mass"...... (It should say after it) now glue some 80 grade emery paper to a piece of 3"x2" start the engine, have a fellow operative start the bike and hold the bike at aproximately 5000 rpms, with your emery paper cladded staff, hold this against the flywheel to remove any burrs created or left from the plugging process, a slower rpm can be used but may add 1/2 hour to the process and increase service time and expense.

I did it to a Triumph engine.

and "using a board for leverage." That's rich.

Never attempt to clean a sludge trap whilst the crank is in situ, the sludge is compressed hard particles and no matter how good you at cleaning they will, by the nature of the beast, get to the big ends and sit there waiting to destroy the shells at first startup. A short cut to an engine rebuild.