Sidecover bearings

Discussion in 'Whizzer Motorized Bicycles' started by Quenton Guenther, Jan 18, 2009.

  1. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    "If it ain't broke, don't fix it"

    The original Whizzer company supported the right side of the crankshaft with a Torrington needle bearing mounted in the sidecover. The WC-1 new edition motor used a similar needle bearing. The NE motors sported a new sidecover that was thicker so that allen screws could be used to attach it to the crankcase. The original Whizzer used different thickness spacers to keep the crankshaft centered, the new company didn't make any provisions to keep it centered. Often on the new generation motors the crankshaft will move sideways, but usually isn't a real serious problem [unless you are running at "Bonneville"].

    I have 3 motors on my bench from owners to rebuild. One is a WC-1 with a Westman cylinder, and the crankshaft is "solid". The second motor is a 2006 NE, and the crankshaft moves approx. 1/8" side to side. The third motor is a 2008 NE, and the crankshaft "wobbles" and moves from side to side approx. 3/8". The play on the 2008 was way too much, so I removed the side cover to see what I needed to do, and to my surprize, the German needle bearing wasn't there, instead a #6904 ball bearing was mounted in the side cover. The bearing was so loose in the cover it fell out when I turned the cover over.
    I was still in shock that the quality needle bearing had been replaced with thin ball bearing. I quickly located my bearing book and looked up the number, sadly here are the facts. The bearing is called an "Extremely Light Plain Ball Bearing" and has a very, very, very low rating of 1824 @ 1000 RPMs. The original needle bearing is 12 MM wide, whereas the replacement is only 9 MM wide. Not only is the new bearing much thinner, but it is recessed deeply into the side cover. They also located 4 washers on the end of the crankshaft to help make up the extra space, but only a part of the crankshaft rides inside the bearing [very little support]. The earlier NE motors that used the needle bearing enjoyed complete crankshaft support and a bearing that was rated with a load capacity of 12100 [static], about 15 times better than the current ball bearing.

    Was the bearing downgraded because of money? I have never had a problem with the Vintage needle bearing, I have never had a problem with needle bearing in any of the new edition motor. I will post several photos to show what I found.

    Have fun,

    Attached Files:

    Last edited: Jan 18, 2009

  2. KilroyCD

    KilroyCD Active Member

    Incredible. It doesn't take a rocket scientist to realize that the ball bearing will ultimately fail, and then what kind of catastrophic damage might follow? :thinking:
  3. go-rebels

    go-rebels Member

    Who are the Engineers in Taiwan that approved this change! I can hardly believe that there is any type of Engineering Change "process" by which there is an analysis made and some "Chief" engineer ultimately signs off on the request.

    The cost of such lack of control is warranty $$$ and disgruntled customers. What must the head office in Texas be thinking (assuming that all warranty repairs don't go directly to Quenton (!)?
  4. Mountainman

    Mountainman Active Member

    wooo is me -- a simple comment to make from up top the old mountain

    it does make one wonder -- what the heck is going on

    usually we wish to improve THINGS so as to be even stronger

    going in the other direction does not make sense in the long run

    I want my motor bike THING to be sturdy
  5. RdKryton

    RdKryton Active Member

    I am sooooo glad I have the needle bearings. With the added power I have from the upgrades that have been done I don't believe the ball bearings would hold up in my engine. I may be wrong but I don't want to find out the hard way.

  6. august

    august Member

    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)
  7. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi August,

    It seems new Whizzers are somewhat like the weather, if you wait long enough it will change. Thank you for taking pictures and sharing them with us.
    I was hoping [wishful thinking] that the 2008 NE motor I was working on was just a case of Joe in Taiwan running out of good bearings and grabbing anything he could make work. But after seeing your crankshaft it is clear that the motor I have was just a link in the evolution of the NE motor. The motor I am working on has 4 spacers between the crankshaft gear and the bearing, whereas your motor has the end of the crankshaft "machined" with a ledge to replace the spacers. Of course this opens the door to ask several new questions. Is the bearing in the side cover the same as the one I have? Does the gear on the crankshaft have a larger I.D. than all the previous motors? Is the crankshaft bearing race surface 20 MM, if so what is the O.D. of the ramp the gear is on, or has the end of the crankshaft but cut to under 20 MM? The ball bearing in the 2008 NE motor is 9 MM wide, O.D. 37 MM, and a 20 MM I.D. All previous crankshafts had a hardened surface to ride inside the needle bearing in the side cover, is the surface hardened on the new version?

    I did notice the bearing in the side cover is the same depth on your motor as the one I am repairing. It looks like the crankshaft end is longer and therefore would sit deeper into the bearing [a good thing]. Another good thing is don't think there were more than eighty five 2008 NE5 Whizzers produced.
    For anyone owning one of the 2008 NE5 Whizzers with the same setup as I just discovered, there are several modifications possible. I will list them in order of poor to what I consider the best fix. First option is to make a spacer and place it between the bearing and the side cover to cause more of the crankshaft to fit into the bearing race for better support [poor, because it still uses the "Extremely Light Plain Ball Bearing" made in Taiwan] FTR, Not long ago a certain company was bragging to me about how they got rid of the cheap Taiwan bearing in their automatic clutch and replaced it with a quality German bearing. Second choice to modify the motor I am working on, would require replacing the sidecover with a NE cover [#2013NE $58.95] with the good ole' German needle bearing [A direct fit, and the best solution, however are they available?], and the third and still a great choice is to replace the sidecover with a WC-1 cover [#2013 $54.15 + screws].

    The difference between the WC-1 and the 2005 to 2007 NE sidecover is the mounting screws and the thickness. The NE sidecover uses allen screws whereas the WC-1 uses phillips "cupped" screws [#93600-05015-18 $8.50 per set]. I know there are quality aftermarket screws for the WC-1 sidecover made to use the allen head pattern [Whoever has them please call me I want to buy some]. Another difference is the NE sidecover has "Whizzer" etched into the cover, whereas the WC-1 sports a smooth circle on the outside [I will include photo, WC-1 is top right]. Although the NE cover is thicker, the WC-1 is a perfect fit because the bearing races aren't as deep to make up for the wider cover.

    The pictures from August indicates the current and most likely future Whizzer motors will use the ball bearing in place of the needle bearing. I checked all my new NE/SE motors and luckily all mine have the needle bearing sidecover.

    Have fun,

    Attached Files:

  8. bobco

    bobco New Member


    For your allen head pattern bolts for the WC-1, go to and type in 91294A211 and that's for a black oxide M5x14mm flat socket head cap screw.....and number 92125A211 is the stainless steel version...same dimensions and both are .8mm pitch, 10mm across the head of the screw...

    91294A211 is $9.50/100 so you can do 10 engines with this screw
    92125A211 is $11.73/50 so you can do 5 engines with this screw

    I buy machining tools and all of my hardware from these folks...a nice local Ohio Co. Their shipping is lightning fast too!! :D

  9. Hal the Elder

    Hal the Elder Member

    Oscar Has Needles.

  10. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi Hal & Oscar,

    That is great news! I suspect only a handful of NE5 Whizzers have the "Extremely Light Plain Ball Bearing". Checking NE5 motor serial numbers has revealed that only the final production of the 2008 NE5 have the #6904 ball bearing. Most likely all the 2008 NE5 Whizzers use the ball bearing.

    When I find an extra few moments I will remove the sidecover from My Ambassador and see what "lurks" inside. I am still doing research to determine when the sidecover bearing was down-graded. Thanks to August on this site we now know the NE-r uses the light weight ball bearing, but don't know if it is the #6904 because of the way the end of the crankshaft is "cut" down. The jury is still out on which bearing is used in the Ambassador II.

    It looks like the sidecover with the needle bearing [WC-1 or 2005 to 2007 NE] can be installed on the 2008 NE motors if it has the spacers on it from Taiwan. If it is machined [like August's NE-r], I don't have enough information yet to offer an upgrade.

    I will include photos of the bearing specs.

    Please note, the "Extremely Light Plain Ball Bearings" doesn't list any "Features",
    whereas the "Open End Needle Roller Bearings" List "Features" like

    Extremely high speed

    High load capacity

    Extremely low rolling friction

    High lubrication capacity

    Low sensitivity to misalignment

    Just to mention a few.

    This infromation isn't intended to "bash" anyone, any company, or any vendor, just supplying important information to keep our Whizzers in the best condition possible for durability.

    Have fun,

    Attached Files:

    Last edited: Jan 20, 2009
  11. Hal the Elder

    Hal the Elder Member

    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...
  12. go-rebels

    go-rebels Member

    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.
  13. august

    august Member


    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
  14. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    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,
    Last edited: Jan 20, 2009
  15. go-rebels

    go-rebels Member

    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...
  16. august

    august Member

    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
  17. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    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,
  18. Whizzer Motorbike

    Whizzer Motorbike New Member

    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.

    Whizzer USA
  19. ibdennyak

    ibdennyak Guest

    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*. :devilish:

    Last edited by a moderator: Jan 24, 2009
  20. n8ygn

    n8ygn Member

    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.