SuzukiSavage.com /cgi-bin/YaBB.pl General Category >> Rubber Side Down! >> Crankshaft bearing radial clearances /cgi-bin/YaBB.pl?num=1494155154 Message started by kojones on 05/07/17 at 04:05:54

Title: Crankshaft bearing radial clearances Post by kojones 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? Clymer doesn't have anything about this. Suzuki spare is very expensive, NF208 bearing from another source costs about one fifth of that  ::)

Title: Re: Crankshaft bearing radial clearances Post by norm92de 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.

Title: Re: Crankshaft bearing radial clearances Post by kojones on 05/07/17 at 13:31:17 32332E31656E38395C0 wrote: 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  ;)

Title: Re: Crankshaft bearing radial clearances Post by norm92de 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. :)

Title: Re: Crankshaft bearing radial clearances Post by Ruttly on 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 !

Title: Re: Crankshaft bearing radial clearances Post by kojones on 05/07/17 at 22:44:25 0E0F120D59520405600 wrote: 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  ;)

Title: Re: Crankshaft bearing radial clearances Post by hotrod on 05/08/17 at 05:58:56 Bearings made anywhere except China.

Title: Re: Crankshaft bearing radial clearances Post by kojones on 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  :D

Title: Re: Crankshaft bearing radial clearances Post by Ruttly 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

Title: Re: Crankshaft bearing radial clearances Post by kojones on 05/13/17 at 08:38:35 6C4B4A4A52473E0 wrote: 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.

Title: Re: Crankshaft bearing radial clearances Post by Andy RN on 05/13/17 at 20:50:30 080C090C0D0610630 wrote: 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!

Title: Re: Crankshaft bearing radial clearances Post by Armen 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  ;)

Title: Re: Crankshaft bearing radial clearances Post by kojones on 05/14/17 at 10:20:48 445045424648290 wrote: [quote author=080C090C0D0610630 link=1494155154/0#0 date=1494155154]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![/quote] 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  ;D

Title: Re: Crankshaft bearing radial clearances Post by kojones on 05/14/17 at 10:30:55 794A555D56380 wrote: 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  ;) 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.

Title: Re: Crankshaft bearing radial clearances Post by Armen on 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.

Title: Re: Crankshaft bearing radial clearances Post by kojones on 05/14/17 at 12:38:21 1E2D323A315F0 wrote: 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. Yep, you're right, the clearance disappears or gets smaller when installed, depending on the ID of the bearing and the OD of the shaft.

Title: Re: Crankshaft bearing radial clearances Post by justin_o_guy2 on 05/14/17 at 18:51:16 The Nugget 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.

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