Handling Wobble at speed

[Strawhead]

My partner has a sportster 1200C 2003. it has been lowered by use of 11" shocks at the rear and hugger springs in the front. The suspension is as you would expect, on a par with a rigid!! it also has a set of 10" mini apes

The real problem lies with riding it at reasonable speeds, say 60MPH around long sweeping bends, as it leans over when under power the steering starts to wobble and you have to ease up on the throttle.

The tire pressure is spot on as per factory spec, the wheels are not buckled and run nice and true.

is this anything to do with rake and trail?

many thanks

Andy

[Bilbo]

There are a few things you could look at. I don't think it's rake and trail as you haven't done anything to upset that balance.

First, if you have fitted stiffer (as well as shorter) shocks on the rear, you may be advised to get the heavy fork oil from HD stealer to restore the balance.

Secondly, have the adjustment on your headstock bearings checked. It may be that there is some undue freeplay in there.

Check that the rear wheel is lined up correctly.

[Strawhead]

Thank you for the response.

The front already has harder springs and heavier duty oil.

The belt is nicely aligned on the rear, if the rear wheel was out of alignment i would imagine this would cause issues with both belt and handling, I will needless to say check that the alignment is correct though!

will also check headstock!

furthermore, I noticed the instability on her old 883 which had been lowered similarly but that time it had drag bars!

thanks again

[Simon_Y]

Does the thing have the original tyres? You may need to adjust the pressure to the new brand's reccomended level don't forget the standard harley OEM tyres are Dunlop.

You may want to look at the condition of the front wheel bearings wear in these can also cause wobble.

R,

S.

[Strawhead]

Hi Simon, the tires are Dunlops. are the bearings likely to be shot after a measely 6000 miles!!!! (Feeble mileage i know, we bought it just before she became pregnant and it has only been used by me intermittently)

thanks

Andy

[grbrown]

Do both of you experience the same thing?

I had cowhorns on my first Harley and suffered what I thought were similar handling problems. I found it was actually me tensing my arms, especially at speed and when cornering. Apes could easily have the same affect.

If you find nothing wrong, having checked the things mentioned, ride the bike with ear plugs. That is not a joke! The reduced noise levels you experience will reduce tension and may shift the speed, at which things start feeling odd, up the rev range. If that happens you have the source of your problem.

[Strawhead]

Thank you Graham,

I had the same effect with both short drag bars as well as the mini apes. i am usually pretty relaxed on the bike but obviously it always appears to happen on the same stretch of road so i guess it could be a psychological tensing on my part as i feel that it is pretty dangerous!!

when my wife was following me on her sportster the other day she felt unable to keep up with me because of what she termed instability but this was on a straight line dual carriageway with only mild bends!!

will check everything and I will give the ear plugs a whirl

thanks again

Andy

[Urrell]

Check the tightness of the bolts attaching the riser to the top tree.
Mine was very loose causing a very vague and hard to pinpoint wander.

[daddykemp]

You say it was on the same stretch of road......
Could it possibly be the road surface that's a bit rutted and your tyres are falling into the ruts? .Pull over and take a look, and if it is the road then have a moan at the council bods!!! It can't do any harm can it?

[daddykemp]

I was also going to say that as you can see from my avatar that I also run apes (19" ones) and I have no problem with wobbles up to about 75/80mph.
It may be worth, if it's a confidence thing, to look at fitting a steering damper. I believe that Zodiac do one for sporties.