preventing power loss

mrbg

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Joined
Sep 22, 2014
Messages
217
it's BS that these motors with the crappy bearings are being sold, I was on YouTube and saw a British distributor showing the slop in the bearings and the links for good bearings. They sent a bunch of them back, I guess I'll have to contact the guy I bought from and see what kinda warranty they have I imagine they're not going to be happy take them back ! Here's the. YouTube linkhttps://youtu.be/4sFRAQvAkk4
Anyone else
it's BS that these motors with the crappy bearings are being sold, I was on YouTube and saw a British distributor showing the slop in the bearings and the links for good bearings. They sent a bunch of them back, I guess I'll have to contact the guy I bought from and see what kinda warranty they have I imagine they're not going to be happy take them back ! Here's the. YouTube linkhttps://youtu.be/4sFRAQvAkk4
Has anyone been able to return a bad motor ?
 


Will'smotobikes19

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Joined
Apr 9, 2018
Messages
1,578
it's BS that these motors with the crappy bearings are being sold, I was on YouTube and saw a British distributor showing the slop in the bearings and the links for good bearings. They sent a bunch of them back, I guess I'll have to contact the guy I bought from and see what kinda warranty they have I imagine they're not going to be happy take them back ! Here's the. YouTube linkhttps://youtu.be/4sFRAQvAkk4
Not only do they lack tolerances they don’t durbur or clean metal shavings off parts. I just bought a Chinese tap set and you wouldn’t imagine how many burs there are as well as mismatched threads that won’t grab.
 

Will'smotobikes19

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Joined
Apr 9, 2018
Messages
1,578
At this point just buy some Japanese ones, any bearings China makes won’t compare. Low prices may tempt but any country besides China can make stuff better. Italy, Germany, Japan even Taiwan.
 

FurryOnTheInside

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Sep 23, 2013
Messages
3,451
So you can rip the metal shield off one side of the FAG 6202ZZ and press in, but Why did he choose the metal shielded 6202ZZ. Is the choice of the metal sheild because of the heat?
And does the type of bearing mean that the clutch will be less draggy when pedalling?
Is the 6202ZZ able to spin freely under the axial load pushing the inner race to the right that seems to be impossible to avoid? Are there any better bearings for dealing with that?
 
Last edited:
Joined
Feb 15, 2019
Messages
57
So you can rip the metal shield off one side of the FAG 6202ZZ and press in, but Why did he choose the metal shielded 6202ZZ. Is the choice of the metal sheild because of the heat?
And does the type of bearing mean that the clutch will be less draggy when pedalling?
Is the 6202ZZ able to spin freely under the axial load pushing the inner race to the right that seems to be impossible to avoid? Are there any better bearings for dealing with that?
The metal shield is to ensure that no oil is going to get through. It makes that side of the bearing sealed. Therefore if it is pressed in correctly all of the lubricating oil from the gas mixture is going to stay inside the crankcase and not leakout. Also this creates a sealed barrier so you don't have an air leak in the system causing a lean condition. You don't rip one side off, the bearings are made that way with only one side that is sealed with the metal ring. And these bearing will make a big difference in drag and life of an engine. Google different bearing types there are a lot of them when I replaced mine I did some research and learned a lot. SKF brand is the best out there you won't find anyone who can disagree with that.
 
Joined
Feb 15, 2019
Messages
57
I forgot to mention that I found there was excess resistance in the clutch shaft bearings which was discernable just by turning the shaft by hand (after I removed the chain and clutch) On the sprocket side bearing I had to use my exacto knife to pry the seal off with the sprocket in place since I couldn't remove it. So I couldn't get as much BADFISH GREASE in there as I'd like but it's extra lubricating properties hopefully will make up for that. With both bearings greased the shaft turned much easier. People don't realize that a little turning resistance anywhere from crankshaft to rear wheel robs a big percentage of power when the engine is of small displacement.
If you remove the bolt/ housing that your clutch cable passes through on top of the case you can pump grease inside there if you get the proper rubber tip for your grease gun. It's a lot easier because it lubes both bearings on either side. I believe that was the intended design as those bearings only have a seal on the outside they are open inside the case. Fred at cr machine has a video on it. He drills a small hole in the side of the case so you can see it come out when its full i just pump it in until i see a little bit coming out of the bearings then take a small screwdriver and press the seals back in. Way easier than taking covers off both sides and fiddling with the seals and all that. This way you just take clutch cable out unscrew one bolt and fill it up both sides taken care of at once. And who doesn't need a clutch adjustment anyway. Lol hope this helps.
 
Joined
Feb 15, 2019
Messages
57
Almost every time I take mine apart I resurface the head and the cylinder mating surface and yet I still get leaks as is evident by the oil on the cylinder fins. A good design allows compensation for the mating surfaces to distort due to unequal heating (due to most of the heat at the exhaust side). I may make a head gasket out of fibrous gasket material. I've also toyed with the idea of grooving the head and cylinder to accept an o-ring. A lot of motocross engines have o-rings.
Make sure that oil isn't coming from your exhaust gasket. I've noticed if you have a small leak there it tends to blow back on the cylinder while riding and makes it appear to be a head gasket leak. Just a thought.
 
Joined
Feb 15, 2019
Messages
57
I have been considering o-ringing, also. One more thing to point out concerning leaks, the sparkplug mounting surface was not flat on my last engine, luckily I work at a machine shop with a flycutter, otherwise I wouldn't know how to true it up. Finally, I've had sparkplugs that had a bad sealing ring on them.
I've heard copper gaskets are the way to go. You can use them over and over And they won't crack or anything. True??
 

The_Aleman

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Joined
May 2, 2007
Messages
875
Copper is def superior to any reused crush washer! That said, a crush washer works awesome once.
 

FurryOnTheInside

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Joined
Sep 23, 2013
Messages
3,451
The metal shield is to ensure that no oil is going to get through. It makes that side of the bearing sealed. Therefore if it is pressed in correctly all of the lubricating oil from the gas mixture is going to stay inside the crankcase and not leakout. Also this creates a sealed barrier so you don't have an air leak in the system causing a lean condition. You don't rip one side off, the bearings are made that way with only one side that is sealed with the metal ring. And these bearing will make a big difference in drag and life of an engine. Google different bearing types there are a lot of them when I replaced mine I did some research and learned a lot. SKF brand is the best out there you won't find anyone who can disagree with that.
I was talking about the main clutch bearings. The bloke in the video wanted metal shields on his clutch bearings, not on his crank bearings. The ZZ in the product code means it does have two metal seals. The single side sealed bearings are not so common. The both sides sealed ones are common.
 
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