Deceleration Steering Shake

[Jeff.C]

During January pulled the Concours down for Maintenance and repairs in almost three years racked up thirty-four thousand miles.

Rebuilt the rear Suspension & spring change (sag set), swing arm bearings, and all the needle bearings in the arms, rebuilt the front forks & Spring Change ( sag set ), new ceramic wheel bearings front and rear, New Cush drive rubber (the original was rock hard and transmitted every engine pulse to me during cruising ) steering head bearings, Kawasaki had none in stock and was a four-week back order, ( Purchased some All balls from eBay, Something I never Do) and figured pull the front apart next year just to check on the Chinese bearings and if I have the OEM parts by then swap them out.

New Conti Road Attack4 tires, powder-coated rims, EBC Rotors, rebuilt all the brake and clutch cylinders & calipers front and rear, ( Change my fluid yearly so kind of overboard ) EBC pads HH front and rear.

New K&N air and Oil filter, Motul oil, Valve job, thinner head gasket, blueprinted valve adjustment on the workbench, she runs like someone poked Godzilla in the ass!

So, after nine hundred miles and sixteen impressive second gear wheelies up to eighty miles per hour when the front tire softly comes down.

After all that work, imagine me letting off the handlebars during deceleration from 50-40 MPH and experiencing a head shake, 99 percent of the time this type is caused by worn steering bearings, but after everything replaced or rebuilt listed above made me question, what worked loose, or is falling off.

So went through my whiteboard and rechecked, all was good until I got to the steering head bearings, and found both the balls and races dented, must have gotten the set made from recycled Bud Light cans. In my work we only use Timken, or any one of the Japanese bearing manufacturers, figures the one time go out of my norm and get burnt.

Went ahead and replaced them with OEM, smooth as ever once again. Before you tell me, I should have replaced them with Tapered, Do not like the heavy feel of full contact on a heavy bike, and do not mind replacing balls every thirty thousand at the end of the life span.

Can't imagine running this brand of wheel bearings.

 

[2andblue]

Good write-up on the importance of high quality bearings at pivot, steering joints and caution on wheel bearings.

When you blue-printed the valve adjustment did you take a before / after cold compression number? I find this to be a telling number that truly shows the benefit of a valve adjustment and one that can be felt once put into operation. This will be different already due to the thinner head gasket curious what you are seeing now for compression numbers.

BTW - how much thinner of a gasket? The C-14 doesn’t have head gasket issues so I can only assume raising the compression was the motivation. Do you have a manual or oiled chain tensioner? Curious how much different the chain tensioner is adjusting / adjusted to, likely not much but in theory the thinner head gasket will essentially lengthen the timing chain - more slack.

Regardless, sounds you had quite the busy winter.

Wayne

 

[Jeff.C]

Hi Wayne, for me to respond thoroughly as to why I pulled the head, need to share the bike's background. Purchased it at the end of September 2021 from my local dealer who had it stored in a warehouse since 2013, The bike was a Police Enforcer conversion loaned to the city of Myrtle Beach S.C.

Ridden hard for a little over seven hundred miles and given back and the sale of four machines canceled.

Purchased it for way below wholesale, discount on all the parts to return it to Concourse status, before getting it running did a compression test and had three in the low-180s and one in the high170s.

Every valve was scary way out of spec after adjustment three came up to 193ish only one was 187, after getting it running would always in the back of my head felt the valves and seats were pitted from moisture, but might eventually bed in and get better, Moisture is the un-benefit of long improper storage.

January had planned to go back to using the ZX exhaust cam since I already was using the larger throttle bodies.

Did a compression test and was still the same readings after three years and all those miles, now we knew it was mechanical, Rings, Valves?

Time for a leak-down test-cylinder three was leaking out of the exhaust, just a slight hiss at the exhaust port, most would let it go, but not me.

Replaced all the exhaust valves due to pitting on the face and seats and set the lash to within .001 of each so that the lift and duration is equal across the cylinders, also run the tighter side of the specs and use the ZX14 numbers.

The thinner head gasket was more in line, to bring the combustion quench or squish closer to where it needed to be and away from mass production loose tolerance, wanted to run more timing and get the best combustion and overall engine performance.

Run a manual cam chain adjuster, no reason to raise the static compression cause dynamic compression ratio as it is already high enough for a street bike.
All and all this engine when mechanically tuned correctly really just shines everywhere!

Thanks
-Jeff

 

[SethInIllinois]

Well, apparently I just learned something. C14s have ball steering head bearings? My C10 and all my other late-80s-designed Kawasakis have tapered rollers (My ZX600-C actually has the exact same bearings and seals as my C10).

I thought ball bearings all got phased out for tapered rollers by the 1980s.

 

[2andblue]

Thanks for sharing overview of the history and machine’s evolution.

At the end of the day where did you land for the compression, considering replacing the pitted exhaust valves?

Wayne

 

[cmoore]

Jeff.C, the ebay purchase of the All Balls Steering Head Bearings caught my attention. I no longer buy any critical auto or motorcycle parts from ebay or Amazon. Too much cheap chinese fake crap. I was recently burned with some fake Denso plugs for my Tacoma. Never again.

 

[Jeff.C]

Well, apparently I just learned something. C14s have ball steering head bearings? My C10 and all my other late-80s-designed Kawasakis have tapered rollers (My ZX600-C actually has the exact same bearings and seals as my C10).

I thought ball bearings all got phased out for tapered rollers by the

Taper bearings have a place, but did not replace ball bearings!

 

[Jeff.C]

Jeff.C, the ebay purchase of the All Balls Steering Head Bearings caught my attention. I no longer buy any critical auto or motorcycle parts from ebay or Amazon. Too much cheap chinese fake crap. I was recently burned with some fake Denso plugs for my Tacoma. Never again.

Hate to say it! I knew better but rolled the dice hoping for at least till the OEM arrived and maybe push it out further, no one to blame except myself.

All Balls is not fake Chinese crap, it is real low end Chinese crap sourced from various overseas suppliers and the last few years have saturated the markets.

If you look at the dust covers on All Balls wheel bearings, you will notice the manufacturer name is missing but the industry part number is there.

The two manufacturers in china that supply all balls are KML & RB Tech, both are listed as Tier 3 bearing factory’s

 

[Jeff.C]

Thanks for sharing overview of the history and machine’s evolution.

At the end of the day where did you land for the compression, considering replacing the pitted exhaust valves?

Wayne

If I remember the compression was even across the bank mid 190s and leak down showed 8 percent so in our world that close to perfect.

 

[fartymarty]

.........replacing balls every thirty thousand at the end of the life span.

So my never serviced nor replaced original OEM steering head bearings are dust at 128,000+ miles?

 

[Just Cliff]

So my never serviced nor replaced original OEM steering head bearings are dust at 128,000+ miles?

I don't know how there still functioning at that mileage with no service Marty. I replaced mine the first time around that same mileage, but they had been serviced also. I replaced them the second time with about the same mileage on them, but again they were serviced.

They are rather easy to service without removing forks or even the front wheel.

 

[Jeff.C]

So my never serviced nor replaced original OEM steering head bearings are dust at 128,000+ miles?

Have no idea Marty, only you can answer that!

-Jeff

 

[fartymarty]

I don't know how there still functioning at that mileage with no service Marty. I replaced mine the first time around that same mileage, but they had been serviced also. I replaced them the second time with about the same mileage on them, but again they were serviced.

They are rather easy to service without removing forks or even the front wheel.

Have no idea Marty, only you can answer that!

-Jeff

Well they feel fine when I'm riding, and I've tried to get them to show some play or clunking by going forward a few feet and hit the front brake hard....seem fine. I'll have to take my forks off again cause they are leaking around the seals after only 15,000 miles after the dealer replaced the seals...maybe while those are in the shop (a different one this time) I'll take a closer look at my steering head bearings.

My initial response was more in reference to your (Jeff C.) remark about them only being good for 30,000 miles, seems a bit short to me.

 

[Jeff.C]

Hey Marty, my view on things tends to lean more towards perfection protecting myself and customers, let me explain my position, Marty, As a partner of an Independent repair shop mostly V-Twin performance, my job is to inform and educate the customer to make the best-informed decision.

Let me give you an example of how I operate, you bring me your bike for the front fork seal repair, and During the drop process I greet you and find out things about your past maintenance, you sign the repair order for me to diagnose your issue and to come up with a plan of PROPER repair.
I called you and say Marty looking over the front forks it appears the hard chrome is wearing off and there are some scratches I cannot stand behind sanding them out, Also since you mentioned to me that this bike was bought new by you and has been super reliable for one hundred and twenty-eight thousand miles with just tires and fluid changes, we are advising new fork tubes, slider bushings, and steering head bearings, because of the following reasons and explain what the failure consists in the short term, Here is your estimate I do understand Marty that it is more then you expected wanting to reseal just the left fork leg and you need to think about this!

You call me back and say Jeff I just want to fix the left leg, I say Marty sorry to hear that, and your bike will be off our lift and parked in the spot you dropped it off, please see Vanessa at the service desk to sign that you refused the repairs and she has your keys, Sorry Marty we could not build that relationship and wish you the best.

I perform that ritual ten times a week and just know shops and dealers are in a race to the bottom and are happy to take your money, not us we are three months out and have been that way for six years.

Those bearings are small and have a very small contact patch, Kawasaki did that for light steering and feedback something you lose with tapered, Goldwing’s use the same setup as most high-end Italian and some Japanese sport bikes The Concourse is heavy, and in my professional opinion, thirty thousand is an honest lifespan. Cant respond as to why you do not feel or what you perceive as alright could be a horror show for me riding your bike, not insulting you but we become acclimated to what is between our legs.
see it all the time on guys riding bikes that have not had a valve adjustment since they owned it, the bottom of the header is rusted out and leaking but insist on asking me for an estimate to install sprockets for more acceleration!

I do not apologize in advance if I sound arrogant on this forum, as more and more realize this is not the forum or place for me to share or educate or make people read what I see feel and do five days a week, so please do not take what I write as being an ass it's not that at all, it's more of just being certain and standing 100 percent of what Jeff does.

My advice to you as a Human is to find a repair shop that asks you a lot of questions and can come up with a plan to repair your bike correctly.

Peace out
-Jeff

 

[Just Cliff]

I agree with both of you. As for Marty 30K seems a little short & I do run mine much longer, but that's with regular greasing & correct torque setting. If I was in Jeff's shoes & was a qualified mechanic with a shop, I'm sure I'd do a lot of things more often than I do.

Also, I really like his take on how to perform repairs, all or none. That's the way I worked when I was in business (different type), do it correct like I thought it should be done or call someone else. Otherwise, you'll probably be calling back latter complaining about something.

I did replace my lower tubes at 131,000 because the hard chrome was wearing off as Jeff mentioned. This could be where you at now & possibly wasn't visible 15,000 miles ago.

When you do pull your bearings Marty, they are bound to be a bit crusty even though you don't feel it. Water is bound to creep in a little over time.

 

[Jorge]

Just some general comments from someone who's been involved with bearings, mostly ball bearings, for a long time.
Chinese steel mills do not care to.make steel that is clean enough to use on bearings, and they make seals from knock-off materials (lowet quality) to reverse-engineered designs - not a good combination.
Dirty steel means they leave inclusions, which are starting points for bearing failures.
There are many types of bearing failures, two biggies are bearing spalling, and corrosion.
Spalling is where a bearing goes from smooth to rough because the inner race develops a "pothole". Spalling can happen with good grease and seals, but bad grease can encourage it. Dirty steel really accelerates this.
Corrosion happens when water/junk gets past the seals. If the seals get hard, wear our, or are just a poor design, they will not seal. Most bearing issues I've seen on bikes appear to be corrosion related.
It's easy to get good quality bearings. Murph carties top-quality ones.
You can also buy them from industrial supply places like Grainger...often in-stock.
For only a few more dollars, get good ones.