SuzukiSavage.com - Crankshaft bearing radial clearances

kojones Full Member Offline SuzukiSavage.com Rocks! Posts: 223 Finland	Crankshaft bearing radial clearances 05/07/17 at 04:05:54 The flywheel end roller bearing in my bike has a small clearance when rocking the crankshaft up and down, how much clearance should there be in a new bearing or how much is allowed? Clymer doesn't have anything about this. Suzuki spare is very expensive, NF208 bearing from another source costs about one fifth of that
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norm92de

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Re: Crankshaft bearing radial clearances
Reply #1 - 05/07/17 at 13:17:16

Kojones
Suzuki's manual doesn't say anything about crankshaft bearing play.
My guess would be basically zero up and down play.

They do give con-rod deflection as 3mm and big end side clearance as 1mm. Also crankshaft run out as .05mm which may relate to your question. The balancer spring free length should be 10mm.

Hope this helps. If I had it down that far I would not be skimping on bearings.

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kojones

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Re: Crankshaft bearing radial clearances
Reply #2 - 05/07/17 at 13:31:17

norm92de wrote on 05/07/17 at 13:17:16:

Kojones
Suzuki's manual doesn't say anything about crankshaft bearing play.
My guess would be basically zero up and down play.

They do give con-rod deflection as 3mm and big end side clearance as 1mm. Also crankshaft run out as .05mm which may relate to your question. The balancer spring free length should be 10mm.

Hope this helps. If I had it down that far I would not be skimping on bearings.

Excellent, thank you! That .05mm might be just what I need. Have to check the play with plastigauge, really hard to measure with a feeler gauge.

Not skimping on bearings, the cheaper alternative is equal or better quality than the stock Koyo Wink

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norm92de Serious Thumper Offline SuzukiSavage.com Rocks! Posts: 1180 El Paso TX Gender:	Re: Crankshaft bearing radial clearances Reply #3 - 05/07/17 at 14:28:39 I have always found that spec bearings are just as good as the OEM types from any bike.
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Ruttly

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Re: Crankshaft bearing radial clearances
Reply #4 - 05/07/17 at 14:38:23

Is the bearing on crank or in cases ? Or is lower end still assembled ?
Only way to measure it is with a dial indicator.
Flat roller and ball bearings have different specs.
If replacing bearings get the Suzuki bearings or you will regret it.
Wrong or cheap bearings will be a bad decision.

The engine YOU build is the difference between riding it and pushing it !
When building a engine it is not the time to get cheap , unless you prefer pushing to riding !

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kojones Full Member Offline SuzukiSavage.com Rocks! Posts: 223 Finland	Re: Crankshaft bearing radial clearances Reply #5 - 05/07/17 at 22:44:25 norm92de wrote on 05/07/17 at 14:28:39: I have always found that spec bearings are just as good as the OEM types from any bike. Yes, as the OEM bearings are spec bearings in 99 percent of the cases
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hotrod Senior Member Offline SuzukiSavage.com Rocks! Posts: 326 NC Gender:	Re: Crankshaft bearing radial clearances Reply #6 - 05/08/17 at 05:58:56 Bearings made anywhere except China.
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kojones Full Member Offline SuzukiSavage.com Rocks! Posts: 223 Finland	Re: Crankshaft bearing radial clearances Reply #7 - 05/13/17 at 06:28:40 Measured the play (case assembled) with a dial indicator, 0,03mm = 30um Could be a new C2 bearing when compared to internal clearance charts
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Ruttly Serious Thumper Offline Thumpers Rule Posts: 5096 Manteca , CA Gender:	Re: Crankshaft bearing radial clearances Reply #8 - 05/13/17 at 08:35:27 Is that with new bearings ? Be sure to take the measurement as close to the bearing as possible, not at the end of the shaft
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kojones Full Member Offline SuzukiSavage.com Rocks! Posts: 223 Finland	Re: Crankshaft bearing radial clearances Reply #9 - 05/13/17 at 08:38:35 Ruttly wrote on 05/13/17 at 08:35:27: Is that with new bearings ? Be sure to take the measurement as close to the bearing as possible, not at the end of the shaft Nope, with the old 50000 km driven bearings. No need to replace them as they are like new.
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Andy RN

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Re: Crankshaft bearing radial clearances
Reply #10 - 05/13/17 at 20:50:30

kojones wrote on 05/07/17 at 04:05:54:

The flywheel end roller bearing in my bike has a small clearance when rocking the crankshaft up and down, how much clearance should there be in a new bearing or how much is allowed?

If you have time, please post a picture of the parts you are talking about, and how you are measuring them. I'm a beginner, and it would help me learn. Thanks, and hope you are staying warm in Finland!

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Armen Serious Thumper Offline Half-Witted Wrench-Jockey from Jersey Posts: 1452	Re: Crankshaft bearing radial clearances Reply #11 - 05/14/17 at 04:38:27 If the bottom end is assembled, and you are moving the flywheel up and down and feeling any play at all, I would replace the bearings. It won't be getting any better by itself
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kojones

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Re: Crankshaft bearing radial clearances
Reply #12 - 05/14/17 at 10:20:48

Andy RN wrote on 05/13/17 at 20:50:30:

kojones wrote on 05/07/17 at 04:05:54:

The flywheel end roller bearing in my bike has a small clearance when rocking the crankshaft up and down, how much clearance should there be in a new bearing or how much is allowed?

If you have time, please post a picture of the parts you are talking about, and how you are measuring them. I'm a beginner, and it would help me learn. Thanks, and hope you are staying warm in Finland!

Unfortunately I didn't take any pictures when measuring, but here's a video that explains it quite well, altough this is the axial clearance, not radial.
https://youtube.com/watch?v=tIUrVJs-iDE

Luckily it's not that warm yet, as my Savage is still under progress Grin

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kojones

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Re: Crankshaft bearing radial clearances
Reply #13 - 05/14/17 at 10:30:55

Armen wrote on 05/14/17 at 04:38:27:

If the bottom end is assembled, and you are moving the flywheel up and down and feeling any play at all, I would replace the bearings.
It won't be getting any better by itself Wink

There should be a small clearance in a new bearing as well, the bearing in Savage is a regular Koyo NF208 without any other markings , the first digit (2) tells that it's a cylindrical roller bearing and the last digit gives the diameter of the hole when multiplied by five (40mm)

http://www.ntnglobal.com/en/products/catalog/pdf/2202E_a08.pdf
On pages 4 and 5 are the radial internal clearances for cylindrical roller bearings, and the measured 30 um is well within the specs of a new bearing.

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« Last Edit: 05/14/17 at 11:59:55 by kojones »

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Armen

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Re: Crankshaft bearing radial clearances
Reply #14 - 05/14/17 at 11:47:51

In applications such as the crank and trans bearings, the bearing would be pressed onto the shaft. The most common clearance I've seen are C3 bearings. This allows the bearing to be pressed onto a shaft, and roll without binding. Once the bearing is pressed onto the shaft, that clearance all but disappears. If I feel any up and down play on a crank end installed in a crankcase, the motor comes apart and new bearings go in.
Do as you wish. I only base my comments on 40 years of working on bikes and doing mechanical fabrication, going to factory service schools, and building bikes that won a few national championships.

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In theory, theory and reality are the same. In reality, they aren't...

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