Getting Sea Sick in the corners

I am trying to track down the cause of my bikes wavy feel in harder corners. It only happens at about 60+ in corners that the bike almost feels as if it is going over waves. I start feeling a rather odd rise/lower, almost as if the rear tire is changing diameter on me. I am going to stiffen up the front springs, but I am wondering if this is something that others have encounteded or if I would need to go back and brace my frame, and then move forward.

Also, I have stock tires, wheels, and front springs with 15 wt oil. The rear has springs that are about 0.5" shorter and stiffer than stock.

Thanks,

I'm not shure what u are experiancing since kz's normaly wallow in the corrners ,but u may want to check the swingarm bushings.u may as well check the steering stem bearings while your at it.

check your swingarm bushings or bearings in case they have been changed any play back there will cause those symptoms take it easy until you have checked that if it trys to stand up in the corners check your steering head bearings as well. ride safe until you check them.

Sounds like rear shocks. How old are the ones on the bike, and what brand?

Swingarm bearings are new and freshly greased. I put them in myself (maybe that is the problem). The steering bearings are also new tapered ones. Shocks are 1978 vintage, but off of a larger bike. The stock ones were rusted and blown so I switched them out. Would it likely be a suspension imbalance? I will admit that I haven't touched the rear shocks as far as pulling them apart and cleaning/overhauling. They have a pretension which is set one step from softest, and a damping or rebound setting at the top.

Overall it does fine for handling, even at 60-70mph in other corners it does fine, it only seems to be a couple of flatter road sections with corners that I pull at 70mph in a family car with no problems (well, the tires chirp a little :whistle: ). So, at 60-65 I get the wavy feel, almost like the road isn't quite smooth, on these corners. It is an up/down but not a harsh one. Closest feel I have to it is riding on a flat tire. Anyways, a little unnerving so I am trying to track it down.

Would bracing the front forks help, or would that just add to the problem unless I brace the frame as well?

i have four position koni shocks in the rear and i can get sea saws going if i leave the settings too harsh or too soft for passenger or single riding...leading me to focus on the rear od your bike...
if you were getting a pogoing up and down at constant highway traffic in a straight line.... that felt like a big egg shaped front rim/tire i would focus on the front end.....
i had a pogo front following traffic at 50-65 straight lines... and found the p.o had some wrong/short/soft springs in the damn forks...new progressive springs ,new fluids, a 1" spacer jammed in the top of the springs... and some aftermarket air caps set at 9-11 p.s.i....i was smiling the firs time it left my street on it...and have forgot allready just how bad it was.....
yours is in a corner..i thin k swing arm?shocks/drive line lash/ bad tire /?????????good luck

As for the tires, they are new, granted I got the IRC flame tires so maybe they really are meant for cruising and not cornering. I hope its not the tires, I'd hate to have to wait to wear them out prior to fixing this. I'm on to tight a budget to change them out now, I'd just have to slow down and take it easy for a few thousand miles.

if you have replaced the swing arm bushings and rechecked the torque on the swing arm pivot and redid the steering head bearings check forplay and readjusted new bearings will often need that then i'd probably go after the tires those irc's are what we in the bussiness fondly call rim protectors that is about all they are any good for break down and by a decent brand name and i'll bet most of your problem will go away. look at dunlop michelin bridgestone or metzler any of the big names depending on how hard you ride you can very easily over match the tires you have on there now. look at the makes that the road racers use i'll bet irc is not one of them metzler makes one of the finest street tires available for older bikes and latly i have been using bt-45 bridgestones on my 1075 street bike and have been quite happy with those but i don't know your ridding habits i just know mine and i wouldn't put junk tires on unless it was an emergency i value my hide and my bikes too much.

Ok, checked the front springs and they are within spec (20.875" measured vs 20.55" spec). They are the stock springs as they are same turns and diameter except for the last 4 turns where it tapers a little and has the springs compressed.

I am looking at a set of rear springs from a KZ as I think the ones I have are just too stiff compared to the front. Also, I am going to machine some 1" spacers if I get some time this week to preload the front and will change out the fork oil at that time to some 30w synthetic motor oil.

As for my tires, I don't think the IRC's are to blame, they felt stiff enough in the side walls to not be flexing in the corner. I am going to try a few other things before I start changing tires. My swingarm is still torqued to spec as is my steering nut and I do not feel play in either of them. I am going to check my front wheel next and try to stiffen the front and soften the rear and see if I can get them to balance.

I have at least a week of no riding to try and get things worked out as I am waiting for new clutch plates and springs to address another issue that popped up with my bike. With any luck I'll have it together and ready for another try in time for March.

Thanks for the help so far.