Motorcycle Repair: STEERING, rear tyre, extended swingarm

Question
-Hi during turning the bike wants to go in a straight line you have to pull the bike round to get round a bend. it has a single original mono shock no notch in steering now but there was but had new bearing put in. rear tyre is not very old with loads of tread. it is now a single seater so riding position is a little more forward.
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Followup To
Question -
HI I BOUGHT A 1200 BANDIT WHICH HAD NO BODYWORK BUT GOOD ENGINE ETC. WHEN I PUT ALL THE NEW BODY WORK ON IT IT IS GREAT IN A STRAIGHT LINE BUT IS VERY VERY HARD TO GET ROUND CORNERS. WHAT SHOULD I LOOK AT FIRST. MY THOUGH WAS MAYBE THE JMC SWING ARM WAS TOO LONG. YOUR EXPERT OPINION WILL BE GREATLY APPRECIATED. CAN I SEND A PIC OF THE BIKE WHICH MAY ALSO HELP.
YOURS D JAMES.

Answer -
Hi Dodgey,

Can you be more specific when describing what occurs during a curve? What do you feel, at what speeds, does it have rear suspension or a strut? Do you feel a notch when turning the handle bars? How old and what condition are the tires? Is the center of the rear tire worn from smokin' burnouts?

I'll try and help ya with your replay.

Respectfully,
Mark Shively

Answer
Thanks Dodgey,

I know the "straight line steering" feeling you described. Gyroscopic effect going on.

I suspect the head stem bearing is too tight. Try loosening the nut and using a torgue wrench and tigheten to spec.

If that doesn't fix the sensation, I would suspect the extended swingarm having some effect.

If you learn the cause, please advise so I can shre the knowledge with others.

Send me a pic if you can. Sounds like an awesome ride.

mshively1@woh.rr.com

Mark