possible mistake in doc .....???

miragev said:

like wrote in a previous post yesterday i'm rebuilding my 01 470
so i thought i would put in the upgraded roller bearings mentioned in the doc . which is in when rebuilding an engine section ..470 ..the bearing number there is SKFNJ2206ECP
i went to an offocial skf dealer they showed me the bearing it is 10mm to wide approx the number they gave me which are the same size as the original 6204 are NJ206ECP could there be one to many 2's in the doc's bearing number because there is no way the 2206's will fit THEY ARE WAY TO WIDE also according to the skf dealer they don't do a c3..in the roller bearing series aswell only standard ..am i right or am i missing something here ...??

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Yes, that extra 2 is a typo- NJ206 is the correct size roller bearing for the mains.

RE: Re: possible mistake in doc .....???

Koyo NJ206c3 should work for the roller, wide part next to the crank.Many have substituted to a deep groove ball bearing #6206c3 .If using the roller always preheat the inner race either factory tool or substitute ,no flame or direct heat.Some say to use the 6206c4 but be careful to exactly measure the shaft to bearing tolerance.

RE: Re: possible mistake in doc .....???

Koyo make the nj206 in c3.The c4 ball bearing must have a presicion fit on the crankshaft,if too loose the bearing will have excessice running clearance and rumble,if too tight it will have too little running clearance either during operation or during temp rise.
The roller bearing has advantages with respect to load while a deep groove ball has advantages to with respect to alignment and ease of instalation and initial cost.
The crank bearings should last in excess of 100 hrs,but keep in mind they are a part that works hard on these engines
On occasion when the counter balancer bearing fails it also damages the crank brg on that side and vice versa .

Hi there folks,

thanks for the notification, good to have attentive members around!
Comments on the Doc are always appreciated.

Just fixed the part# typo

I'm not sure about the C3 extension...

So if anyone can confirm... :roll:

Thanks,
Maddel

Re: RE: Re: possible mistake in doc .....???

miragev said:

i have just spoke to a husaberg dealer who said there have been problems with the collar snapping of the nj206's roller bearing's inner collar where it meets the crank has anybody had this problem and he advised me to stick with the c4 6206 what do other people think

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ok miragev

first of all thanks for pointing out the typing mistake. the roller bearing upgrade takes greater loads than the ball race however, everything must be spot on - that's all tolerances and unless you're prepared to measure them i'm not sure i'd upgrade. basically a ball race is very forgiving of all tolerances and the concensus is that they were never getting 'knocked out' so the upgrade is unnecassary.

there are a couple of ball race upgrades and nsman has mentioned the 'deep grove' 8-ball but there is also a 9-ball upgrade. both would be better and virtually 'slapping it together' will be fine.

if you go to roller then you must or a motor engineer must measure for the correct tolerances. thiis is why the rollers have been knocking out.

standard bearings are cheap and made to loose tolerances. they aren't made for any specific task, however, the C3 and C4 are made to a far higher tolerance and with expansion built in so that you might describe them as perfect: perfectly loose enough!

hope you follow that.

i recommend that unless you are SM, you go 9-ball or the deep groove that's been mentioned.

regards

Taffy

RE: Re: RE: Re: possible mistake in doc .....???

I really do not understand the 8 ball or 9 ball thing Taffy.Every 6206c3 I have ever seen has 9 balls in the cage...

RE: Re: RE: Re: possible mistake in doc .....???

ok then 10 ball!

taffy