Wobbly Acceleration - Harley Forum

Weasel_FXDLI · #1 05-17-2009, 01:53 AM

I'll do my best to exlplain this and if anyone has had this happen please let me know. 04' FXDLI

I was riding down the freeway and jumped on the throttle to pass a truck. The was no strange noice other than the engine over revving, I look down at the speedometer to see it pegged about 1/2 inch past 120, and it felt like the rear end of the bike was slipping to the left. I pulled off the road and took time to clean out my pants and check out my bike. The belt was tight and so was the rear wheel. Cautiously I got back on the bike and headed down the road. every time I would get on it to accelerate it felt as if the ass end was slideing to the left. The bike runs fine and shifts without any issues. Please if anyone might know whats going on let me know.

Weasel

Buzz Kanter · #2 05-17-2009, 05:37 PM

Check to make sure the axle and axle nuts are tight. Check the wheel bearings. Check to see if the wheel is true and the swingarm is tight. If they all check out, I dunno.

unclepsycho · #3 05-17-2009, 06:26 PM

Hi there, Welcome to the forum.

What year is your Dyna?;;;; (Edit: oops I see it is an '04 in your post)
It is wierd that the speedo and the bike are acting up at the same time....
could the back tire be spinning?
was the road wet?
or did the road have sand or something to make the tire spin?
or is there "blow-by" spraying onto your tire from a breather hose??

I nailed the throttle once and didnt notice the sand on the road till the back end did what you describe.

Definately check the axle and swing arm just to be sure [like Buzz suggested]. and look for oil film etc in the back tire area.

let us know what you find.

frisco-rigid · #4 05-17-2009, 10:56 PM

Gosh, what an interesting question/prob..

I'm guessing this is a Brand New prob, yes..????
Has any work been performed recently in or around the rear-end.?

You say the motor Over-rev'd,, soo, did you accelerate at all, alot, none.?

Most certainly check out Buzz and Unc's sugg's.. Good ideas..
OK, if that happened to me the first thing I would do (after clean pants) is lift up the rear end and check to eliminate EVERYTHING and I mean everything..
Alignment, bearings, belt-pulley, belt-teeth, axel adjusters and all the stuff Buzz & Unc said, etc etc.
If you find nothing, slowly work forward, check everything, put your hands on everything to wiggle push pull..
Is it Rubber-mount.? Check top & front rubber motor mounts..

If I didn't find anything I'd lift the front up and wiggle push pull everything.. Even the neck bearings for unusal play..

You will find something..

No offense but unless it's a first-gear Hole-shot you simply don't have enough power to break the rear wheel free unless there is a Loss of Traction caused by debris or oil etc. etc. under the rear tire..
My guess is that if there was enough oil spewed out to cause slippage youda seen it when you pulled over..

Doesn't your Speedometer read off the front wheel..
If yes then I see no reason for it to be affected by anything going on in the rear end.. Weird..

EDIT,,, good info Unc,, I wasn't sure, that's why I asked..

unclepsycho · #5 05-17-2009, 11:09 PM

Ya know, the speedo on my 06 Ultra reads off a sensor in the trans... Dont know about the '04 Dyna's tho.

evoKENevo · #6 05-18-2009, 02:37 AM

Something else to check is tire pressure. When tires spin at higher speeds they expand..when they expand the air pressure in them drops until they contract again...and in the meantime things can get pretty hairy especially if you're a little low to begin with.

I discovered that the

way years ago...and (uhh) just something else to consider here,