Sidecover bearings

[Hal the Elder]

I'll Inform Oscar...

...that he's fortunate in having the superior load capacity of the Needle Bearings in his side plate.

This would be an advantage if a person should ever want to mill the head!

Thanks, Quenton...
HAL

 

[go-rebels]

Although the point has already been correctly made, one needs to compare the "dynamic" load ratings of both bearings. The ball bearing only gives a dynamic rating (@1000 rpm). The needle bearing shows a dynamic rating but it is obscured by glare in Quenton's pic. Assuming is near 10,000lb, that's greater than a 5x rating reduction... something still to worry about.

The bearing is only loaded radially by the crankshaft so the rated loads as shown in the manuals are absolutely critical! There is really no engineering uncertainty, and unless the engineers know for a fact that their pre-2008 design had a HUGE factor of safety, there's no good reason to down grade the bearing.

 

[august]

Quenton.

I guess I wasn't very clear in my post, when I stated my NE R had the "cheap" bearing.

I should have said it does have the 6904 bearing, which it does indeed have. Sorry for the confusion.

I am looking at ceramic ball bearings as a replacement, they are listed for use in racing motorcycles. Any thoughts on ceramic???

I still haven't come up with a good way to remove the existing bearing from the cover, any thoughts on that???

Regards August

 

[Quenton Guenther]

Hi August,

Thank you for sharing the information.

So far I haven't located a better bearing that will fit into the side cover. The only Ceramic bearings I have located so far has a 42 MM O.D. whereas the #6904 has a 37 MM O.D. I was at least hoping to find a double row replacement, but none have the correct O.D. to fit the side cover.

A little good news, the odds are high that an earlier side cover could solve your problem. It all depends on how wide the ledge is on your crankshaft. The WC-1 or 2005 to 2007 NE cover most likely will fit, and worse case would you might need to press the needle bearing a little deeper into the sidecover [easy to do]. Another option would be make an aluminum spacer to fit into the 37 MM hole in the side cover to reduce it to fit the #KX2012 needle bearing. The O.D. on the KX2012 is 26 MM, so the spacer would be 37 MM O.D. and the I.D. would be 26 MM. The spacer would need to be 12 MM wide.

I am sure Whizzer has plenty of WC-1 covers in stock, but I doubt they have many [if any] of the 2005 to 2007 NE sidecovers on the shelves. If converting to the WC-1 cover it will be necessary to change the mounting screws. EZ Motorbike Company is considering stocking a better version of the WC-1 sidecover screws [chrome, or stainless steel allen type] if there is a demand for them. Please look at the covers shown on an earlier post, and you can tell the WC-1 cover because the "circle" on the side cover is smaller and doesn't have the Whizzer logo embossed.

I would advise you on the removal of the #6904 bearing from your sidecover, but I don't have any experience with it because it fell out of the cover I am working with, and is loose when re-installed. I would guess a good way is to bend 2 pieces of metal and "hook" them on the inner bearing race and gently tap on the cover and it should easily remove the bearing. Maybe someone on this site might have a better way to remove it.

Have fun,

 

[go-rebels]

I like the use of the aluminum spacer. I would solicit the help of a machine shop to help fit the adapter-spacer into the 37mm ID of the sidecover. The tolerance needs to be just right to get a proper press fit and the only way to do that would be to turn one adapter down in an iterative trial-an-error method until the adapter "almost" fits, thus guaranteeing a good press fit. Then that one adapter needs to be trial fit against a group of side covers to see that the fit is consistent. Then the ID needs to be turned to provide a very tight slip fit to the bearing. When the adapter is pressed into the cover, then the ID of the adapter will shrink a little and provide a good press fit for the bearing. Once the first adapter is cut for the proper ID and OD, then measurements need to be taken and a group of adapters needs to be machined on a CNC lathe all at once to keep the costs low.

The ring adapter will have a 5.5mm wall thickness, and that is sufficient to easily press into the sidecover without buckling.

If someone can generate the measurements, I can facilitate the manufacture of the adapters.

Just my 2-cents...

 

[august]

I found a puller at my friendly local Kawasaki dealer that he let me borrow, so I got the old bearing out.

I did find a ceramic bearing of the right dimensions, but it was pretty pricey at around 90 bucks.

I ordered a replacement bearing of the same dimensions as the old one . It is an SKF bearing, has a dynamic N rating of almost 7000 and it's rated limiting speed of 26,000 rpm. It was not as much , about 40 bucks.

That should be plenty for anything I will do with this motor. I didn't feel like getting into all the spacers and such.

I have made my self feel better any way. Thanks to Quenton for the heads up on checking the bearing placement. I wouldn't have thought to look at that on my own.

Regards August

 

[Quenton Guenther]

Hi August,

Thrilled you found a good bearing, sorry it was expensive.

Many have opted to change the side cover so far, but it costs over $54.00 for the WC-1 version. And almost $59.00 for the earlier NE sidecover. The needle bearing [$17.45] is included with the sidecover.


Does you crankshaft have any side movement? Let us know how the new bearing works out.

Have fun,

 

[Whizzer Motorbike]

Dear all,
Our manufacturer changed the crankshaft bearing with the intention of helping the engine run smoother. So far, the 6904 bearing has been used in over 1,000 bikes and we haven't heard of any failures yet.

Since we are not bearing experts, after reading this, we contacted our bearing suppliers here in Dallas. One of these reps also races dirt bikes. They feel the addition of the 6904 ball bearing is actually an upgrade to the HK2012 needle bearing for this application. According to them, the HK2012's that were being used will cause more friction and will heat up quicker. From what we've read and been told, the 6904 is rated for higher RPMs. In regards to pricing, our cost on the 6904 bearing is actually more than the HK2012 so money was not a factor in this decision. If anyone has any concerns about this change, we would suggest contacting a bearing supplier and asking them which bearing they would use in this application, the 6904 or the HK2012. As August mentioned, there are ceramic ball bearings available for the 6904 as well which cost about $40.00 each (Koyo brand) if purchased from our supplier here in Dallas. The other three bearings in the crankcase are also ball bearings, and there are also ceramic bearings available for these as well but we haven't received any pricing on these yet. We're sure there are many that have different opinions regarding this and are more knowledgeable about bearings than we are... if anyone has an engine problem as a result of this bearing failing and your engine hasn't been modified to the point that it's ready for Bonneville, please let us know as we would like to help you.

Thanks,
Whizzer USA

 

[ibdennyak]

I just took the side cover off of the NE R model I just got.

The bearing is the cheap model, but it doesn't seem to be as deep as what Quenton has found.

By my measurement, when my cover is firmly seated, the crankshaft is all the way through the bearing.

I determined this by holding the bearing, while still installed in the cover up against the end of the crankshaft. With the end of the shaft just starting into the bearing, I measured the distance between the cover and the crankcase, and had over 9 mm distance.

I would go ahead and replace the bearing with a good one, but I can't get the old one out. I tried heating the cover, but there is no place to get any kind of a wedge under the bearing to lift it out of the cover.

I could use some suggestions as to how to remove the bearing without doing any damage to the cover . This bearing is certainly not as loose as the ones Quenton described.

Also , my crankshaft has a shoulder on it to prevent movement I think.

I have added some pictures for your enjoyment.

As a side note to Quenton, I called Dave about my starting problem which I have bugged the H#ll out of you about, and he is going to send me another carburetor to try.

August ( Jack Waechter)

http://s269.photobucket.com/albums/...=view&current=whizzercrankshaftbearing003.jpg

http://s269.photobucket.com/albums/...=view&current=whizzercrankshaftbearing005.jpg

http://s269.photobucket.com/albums/...=view&current=whizzercrankshaftbearing007.jpg

http://s269.photobucket.com/albums/...=view&current=whizzercrankshaftbearing006.jpg

I see you solved the removal problem, but an oooold mechanics trick I learned from an oooooold mechanic is to fill the cavity with heavy grease, and insert a fairly tight fitting object in the bearing ID, and rap it sharply with a hammer. It uses hydraulic principals to remove the offending bearing and works quite well in a *ghetto sort of way*.

Denny

 

[n8ygn]

bearing removal and old mechanics

I was just getting ready to reccomend the old mechanic grease trick I wondered who I told that to. Another way that is the easiest way is to freeze the bearing only rapidly and it will fall out of the side cover us old mechanics use to use r 12 but that is elegal now but they do make other freezeing agent now that can be used. I liked the Bonneyville statement Lee she did too did you catch that. Just another old manic I mean mechanic (Dane) Been turning wrench 37 years but must admit mostly push buttons now a days. PS Has anyone considered Thrust bearings this would stop the side to side motion. Just an idea to add in while I'm at it, now it's time to climb down off my soap box.