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Author Topic:   bearing size?
garyl
Dirt Full Roller

Total posts: 68
posted April 25, 2005 07:22 PM  
new crank,to tight on oil clearance.Do I need 1 under or 1 over size brngs? where do I get them,prefer race bearings. thanks

jpotter94
Dirt Forum Racer

Total posts: 94
posted April 25, 2005 07:28 PM  
you need to polish them to get your clearance..if you got the right bearings going to a 1 under would be too much,and 1 over would make it even tighter..use emery cloth and polish until you get the clearance you need..

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted April 26, 2005 08:06 AM  
What clearances did you get? rod or main?

You would want 1 over bearings, but they might give you too much. You can also use half a standard with half a 1 over and get .0005 over if you had to.

jpotter94
Dirt Forum Racer

Total posts: 94
posted April 26, 2005 08:21 AM  
have to clarify my first post,DO NOT USE EMERY CLOTH TO POLISH,i wasnt paying attention when i posted that late last night,what i meant to use to polish is scotch bright,it will not hurt anything and gets the best finish nor will it wear out anything.we put out about 30 motors a year.now depending on what your clearences are at now you may need to get undersized bearings but if you are relatively close take my advice and polish the bearing with scotch brite and get your clearence.be careful when doing it as a little polishing goes a long way!

awkwardjeff
Dirt Forum Champ
Total posts: 562
posted April 26, 2005 10:01 AM  
Okay, I copied this from your other post...Ford5, you are correct, and I should have watch my wording........they do make bearing that are .001 over and .001 under........one is for new cranks that are too tight......the other is for cranks that have been polished from standard and are now a little loose...... since the crank is too tight OVERSIZED bearings are what you need....... when we talk bearings we are talking about inside diameter......and that size needs to be bigger to gain more oil clearance. thus making it a oversized bearing

...about oil clearances. You have 3 different threads wanting the same information. Obviuosly you didn't believe my answer to your question. jpotter94 has given you advice, and it's the same advice......along with the other option of scotch brite the bearings, when we are talking about a .0005 to .001 clearance it's hard to keep the bearing round and there is a reason there is a coating on the bearings. jpotter94 also gave you the same option of useing a half from the oversized bearing then a half from the standard size bearing........mixing and matching bearing half will gain you .005......

at this point I would ask, who measured the crank and bearings for you? that person should be able to get you the bearings you need. and if you measured it yourself, that's good, you can find a .0005 but don't know where to get the proper bearings. Most people don't have the tools unless they have the knowledge......


quote:
Originally posted by garyl:
new crank,to tight on oil clearance.Do I need 1 under or 1 over size brngs? where do I get them,prefer race bearings. thanks


sdhnc29
Dirt Forum Champ
Total posts: 934
posted April 26, 2005 04:37 PM  
If it is a race crank, I'd personally send it back to whomever made it, and tell them to give you one that is on size!

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