The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: edboy on 04.05. 2016 22:36
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hi a10 engine builders.
i ve just bought a ngk japanese roller bearing for my engine rebuild. are they any good?
i have an old r and m lrj30, hoffman r130l v3 which look too old to replace. what do you think?
i intend to thrash this engine and wonder if was wiser to pay double for an old stock r and m or hoffman but the problem is that there are different types of r130l.
e.g. 40j 97p - what does that mean?
unfortunately all my local bsa dealers have retired or have passed away and precise information is not in my haynes manual.
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Dont know about NGK bearings... *eek* I took the advise of a couple of experts &
replaced mine with a NSK Nippon Seiko K.K Tokyo Japan # NF206W...
No problems here.. *smiley4*
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thanks wozza, i ordered one today.
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I know their very hard to find but a C3 clearance is recommended The bearing is (should be) tight on the shaft and housing (shrink fit). A standard CN bearing can get a little tight if it gets hot enough eg racing or extended high speed road riding in the Red Center.
Cheers
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i ve seen the triumph bearings advertised with c3 clearance but not the a10 ones. hence my question as to which bearing is best .
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I've run a CN in the plunger for 20 years with no problems. She even made it onto the race track a few times.
Cheers
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I have an original chart from the BSA drawing room and it lists all the bearings that fit all models and it doesnt state any specific bearing other than "normal" bearings.
I have always used CN or "normal" bearings in all my BSA's and have never had a problem.
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Your probably right Brian. I just remember years ago (before the internet) being told by a race engine builder to use C3's for the drive side. As an apprentice F&T we had to work out which grade to use with different interference fits.
Cheers
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Its hard to workout some of this stuff sometimes when there are no hard and fast rules or recommendations, its usually a give it a go and see what happens thing.
Its a bit like the drive side bearing that is meant to be a roller, I use ball bearings in mine and so far have not had a problem. The plunger A10 I had did 45,000 miles on the roller bearing in it and my current s/arm one has done 22,000 miles so far without a hitch and the bearing still feels like new. The reason I use a ball bearing is so I dont have any end float problems.
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I have an original chart from the BSA drawing room and it lists all the bearings that fit all models and it doesnt state any specific bearing other than "normal" bearings.
This chart is great. Thanks for sharing it. I think it's intereting that it's a hand-drawn drawing rather than a typed list.
Richard L.
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Good information
Is there a part number for the ball bearing? and which motors would it fit. All A10's All A7's??
Thanks Keith
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Its hard to workout some of this stuff sometimes when there are no hard and fast rules or recommendations, its usually a give it a go and see what happens thing.
Its a bit like the drive side bearing that is meant to be a roller, I use ball bearings in mine and so far have not had a problem. The plunger A10 I had did 45,000 miles on the roller bearing in it and my current s/arm one has done 22,000 miles so far without a hitch and the bearing still feels like new. The reason I use a ball bearing is so I dont have any end float problems.
Brian that is interesting as when I did my A10 58 GF I just replaced that bearing with what came out of it, a ball bearing which I got from the local bearing shop, not realizing that it should have been a roller bearing.
I have been wondering whether I should replace it after reading some posts here but after reading your post I think I will just leave sleeping dogs lie *thanks*
However you must still set the end float to .0015 because it would loose to much oil pressure if you didn't, I assume you did that.
It would be interesting to hear other comments on the "for and agents" of using roller or ball bearings on the drive side *conf2*
Peter
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RichardL.
The bearing chart would have been an engineering drawing, it was more than likely ink on linen. The size of drawing would have been quite large too.