Replacing bearings

[Farthom]

The bearings in my engine seem to be at the end of their life. I stick my finger in them and rotate them and they all feel somewhat..... sandy. In any case, I would like to head off to a local bearing supply and buy some new ones, but I'm completely in the dark as to what I'm looking for. There seems to be two kinds of bearings, one sealed, one unsealed.

Sealed Markings:
6202Z
AX

Unsealed Markings:
6202/PG
CXCL

Can someone fill me in on what these markings mean?

 

[DaveM]

The bearings are a very common metric size.

The bearings for the clutch use 6202 2RS C3. 6202 is a common metric size, 2RS means 2 rubber seals, C3 means extra clearance for heat expansion. I suggest 2RS bearings for the clutch shaft because there is no oil to lubricate the bearings in the clutch shaft area.

For the crank bearings use 6202 NS C3. Again 6202 is a common metric size, NS means no seals, the fuel/oil mix lubricates these bearings and the crank seals, C3 again extra clearance for heat expansion.

All the 2 stroke motorcycles I have ever had have used C3 clearance bearings but check with your supplier.

Check with the bearing supplier with the numbers I have supplied to see if they agree.

Also get some good quality seals as well, the Chinese bearings and seals leave a lot to be desired! Make sure you tell your supplier what you are using the bearings and seals for, for the crank seals you will need seals that are compatible with fuel usually, Viton if I remember rightly.

Hopefully others will point out if I am wrong in any way?

Regards,
DaveM.

 

[Norman]

Davem gave you some good advice for bearings, but watch out for the bearing dealers some try to stick it to you, you can find these bearing on line by doing a search, if you buy in bulk you will get a break on the price, but I think your just wanting enough for one engine. but it won't hurt to have a price idea before going to a bearing shop so you will know if your getting screwed.
I had a dealing with a bearing shop, I wanted a small bearing, this saleman priced that bearing at $15.00 for one, I knew he was way off base didn't by it, on line I placed an order for the same bearing, $10.00 for a pack of 10 included the shipping same bearing number same manufacture as the higher than jell bearing from the rip off bearing store.
I think an good online bearing seller is baileys bearing, sounds like the Jetson's work place. LOL!
I'll add that you will probably have to order your engine seals from one of the vendors, unless someone found a source for the seal that goes behind the mag rotor it seems to be a bastoid seal. the price for the stock seals wasn't bad less than $10.00 for both last time I checked.
link to bearing.
http://www.baileynet.com/index.php?id=31&productcategory=1000013

 

[DaveM]

Farthom,
The 6202 2RS C3 EMQ (Electric Motor Quality) look like good value. I would buy four of these bearings and just dig both seals out of two for the crank remembering the crank bearings and case seals are lubricated by the two stroke mix. You will need to clean the grease out with kerosine. Easy to do just insert a small screwdriver close to the inner ring and pry out the seal but be careful not to damage the bearing. Thank you for the link Norman. Also Norman is right it pays to shop around.

Regards,
DaveM.

 

[Drewd]

yep, our local bearing supply store, whisler bearing, charges 2-4x more for a bearing than what you would pay online. i almost died when they wanted 49 dollars for 12 foot of 401 chain that i bought online for 14 dollars shipped.

 

[DanielMaia]

Only to figure out..i recommend a good quality bearings, expecially for the crankcase. I bought 2x SKF 6202-2RS C3 for crankcase and clutch side, and are really good quality bearings.

More important of these bearings, is the roller bearings, that connects rod to piston, as knows has top end bearing.

 

[Farthom]

How important is the C3 marking? I have picked up some bearings, but the markings say only 6202NSE. They are sealed with rubber. I plan to dig out the seals for the crank bearings. This is all they had.


Do you think these bearings are bad to use?

What can happen if they dont have the C3 heat expansion marking?

Should I dig out one or both seals for the crank bearing?

 

[littletinman]

Could you just use the bearings for the clutch shaft, take the seals off, and use them in the crank side?

I have a bunch of the clutch side bearings, but have had a hard time finding the other, open bearings anywhere.

 

[littletinman]

n/m found the answer: https://docs.google.com/document/d/1BJQmfhKXxxZKV2swbg80BYJzzT8ySrtFwDKcNrdG750/edit?pli=1

 

[movinfast]

my question is can u replace the brass bushing with the bearings?

 

[mew905]

my question is can u replace the brass bushing with the bearings?

I would imagine so, someone else will have to confirm, but newer motors use needle bearings, and older ones use brass bushings.

 

[JonnyR]

would it be bad to red grease or use cam lube on the wrist pin bearing before i put it in?

 

[movinfast]

ya i know that the new engines use needle bearings but i didnt know if the bores and diameters were the same. on another note i would like to know the same about the crank grease i was told by an old timer who builds race cars it is always best to use zinc monopoly lube one the first start of a new build. he said both on cam and crank. it is thick stuff but still lquid. i would think it would be good stuff in are case too.