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wheel bearings:in or out during powder coat?

kwb210

New member
Picked up a pair of Lester mags that will reside on a 1974 R90/6 next summer. They have lived a variety of lives if you count the layers of paint, very good condition physically, just never lived with anyone who knew how to prep before painting! I am going to have them sand blasted and then powder coated black as they were originally. Do the wheel bearings need to be removed prior to this work? My blaster is good and careful about masking before sand blasting, I was just worried about the heat process. If removed can they be re-used?
Thanks!
kurt
 
I might consider the peace of mind by just replacing the bearings. You're going to have to go through the complete preload process whether you reuse the old ones or go new. Be sure that these Lesters have BMW inner parts...the spacer I believe. I read from Oak that many of the Lesters came with subpar parts and the result were less than satisfactory. If you upgrade the components to BMW parts, the wheels should be fine.
 
Just in case you are not aware of it, powder coat curing temperatures generally range from 375?? - 390??F.

I'd be just as concerned with bearing grease and seal degradation as with blast grit.

My vote would be to remove them.
 
Just in case you are not aware of it, powder coat curing temperatures generally range from 375?? - 390??F.

I'd be just as concerned with bearing grease and seal degradation as with blast grit.

My vote would be to remove them.

What he said, and on top of that when the grease melts, it will ruin the powder coat
 
Great advice

Great advice! I had been leaning that directon but it is nice to hear it from the collective, out come the bearings. Thank you guys! :thumb
kurt

I will probably do a little write up about the bike. Came to me after living downwind from the Hanford Nuclear Reservation. Lots and lots of corrosive damage to the bikes finish, weird, plus a bunch of just plain goofy fixes. So I started by stripping her down like a worker who visited the wrong side of the nuclear plant...yikes. How many cylinder base gaskets do you need to reduce the compression for the use of cheaper gas...:dunno
 
Picked up a pair of Lester mags that will reside on a 1974 R90/6 next summer. They have lived a variety of lives if you count the layers of paint, very good condition physically, just never lived with anyone who knew how to prep before painting! I am going to have them sand blasted and then powder coated black as they were originally. Do the wheel bearings need to be removed prior to this work? My blaster is good and careful about masking before sand blasting, I was just worried about the heat process. If removed can they be re-used?
Thanks!
kurt

Kurt,

From experience, pull the bearings and replace with new ones. Your guy can mask all he likes, but grit will get in and in the end you may destroy the I.D. of the hubs. Lister wheels don't come around every day. You will have to reheat the hubs after you have powder coated to reinstall the new bearings. The temperature will be about 190 degrees F, were as powder coat needs to be at 400 degrees F to flow.
 
Base Gasket

Did this bike come with a gasket?

If yes, then just replace with new.

If not, I wouldn't put one in there. Some Loctite 510 ("gasket eliminator") on the base will give excellent results. (There are many other less-expensive choices that will also work just fine.) This is Oak's current fave, and it sure did the job on my R100RS.

IMHO, whatever issues may arise from 90-91 octane can be resolved by careful tuning of the engine; I wouldn't lower compression but that's just one opinion.

Walking Eagle
 
Did this bike come with a gasket?

If yes, then just replace with new.

If not, I wouldn't put one in there. Some Loctite 510 ("gasket eliminator") on the base will give excellent results. (There are many other less-expensive choices that will also work just fine.) This is Oak's current fave, and it sure did the job on my R100RS.

IMHO, whatever issues may arise from 90-91 octane can be resolved by careful tuning of the engine; I wouldn't lower compression but that's just one opinion.

Walking Eagle

Actually I meant that as a statement not a question, but it reads as a question! The PO had added not one but two base gaskets in his pursuit to lower the need for good gas. Also lots of very personalized wiring, only the person doing the wiring has any inkling of what the wires should be doing. I will get together a story of the new rising of the plain old '74 R90.
 
Agreed:)

Approaching 400F is bad for most bearings. I was taught in gear school, the bearings begin blueing, weakening at these temps. We always could tell an overheated gearbox at teardown, when we visualized the bearings turning blue! A steering head bearing is not the same, but still a bearing and no need exposing them to this heat. Randy
 
Actually I meant that as a statement not a question, but it reads as a question! The PO had added not one but two base gaskets in his pursuit to lower the need for good gas. Also lots of very personalized wiring, only the person doing the wiring has any inkling of what the wires should be doing. I will get together a story of the new rising of the plain old '74 R90.

According to the MAX BMW parts fiche the 74 R90/6 had a base gasket so one needs to be there. I agree with Walking Eagle when it comes to lowering compression. A few pennies more for higher octane fuel = more fun. It's a motorcycle, not a farm tractor. OK some would argue that point but...

I am finishing a top end re-seal at the moment and following Oak's top end manual step by step since it has been years since I did this job. His manual contains addendums on sealing compounds over the years and my understanding is that Hylomar was found to harden up and get brittle over time and then the leaks start.. I read his recommendation on the loctite gasket eliminator however it's hard to find locally in Vancouver BC.

I opted to use this stuff which came recommended by a local wrench of some renown. He has been using it successfully to reseal engine cases, cylinders and various other high heat sealed components. You guys south of the 50th can pick this stuff up almost anywhere. Walmart sells it for $5.59 but NAPA in Canada charges $12. Amazon sells it too. This Permatex Ultra Grey stuff stays flexible which has advantages in this application.

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Take them out!!! The heat and dirt necessary for powder coating will damage a bearing, and it probably won't show up until you are going about 70 MPH on an interstate!

Play it safe
 
Picked up a pair of Lester mags that will reside on a 1974 R90/6 next summer. They have lived a variety of lives if you count the layers of paint, very good condition physically, just never lived with anyone who knew how to prep before painting! I am going to have them sand blasted and then powder coated black as they were originally. Do the wheel bearings need to be removed prior to this work? My blaster is good and careful about masking before sand blasting, I was just worried about the heat process. If removed can they be re-used?
Thanks!
kurt

OUT! The cost for new bearings is minimal for safety.

On sand blasting, see if you have someone in your area that can bead blast with plastic. The Lester mags are soft and not worth tearing the s*#t off the surface. Been there done that from experience.
 
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