My forks are bobbling!

[guest288]

Dropped the forks by 36mm through the yokes on the cougar to aid turning in.
Took the bike out for a cracking ride this morning, made a great difference to the little bike but now I've noticed that above 40mph or so I seem to have a repetative bobble through the bars. The tyre and rim still seem true, it seems as though its in time with the tacho gubbins but I'm not sure.
Any ideas guys?

[johnr]

is the wheel ballanced? tyres usually have a small coloured spot on one of the sidewalls, this is to be put opposite the tyre valve to help with ballance.
is it an up down bobble, or a side to side one?

[guest146]

By lowering the bike on the forks it removes a little  of the bikes self centering and its want to go in a straight line, hence the quick turning, but my guess would be it now shows up even a small out of balance that would not have been noticed before. Maybe a steering damper would help

Ken

[OMEGAMAN]

   I know it sounds a bit strange, but check the REAR wheel balance as this can upset the front (forks).