Building the crank into the casings B50 only

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Mark Cook
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Building the crank into the casings B50 only

Post by Mark Cook » Fri Dec 18, 2009 2:31 pm

Starting with the lefthand crankcase. LJ7/8 zz. outer bearing spacer washer. outer race NF305. Pressed steel retaining plate. (unless you name is Peter and you should have one of my machined ones). inner spacer washer. Inner race NF305. This is the point where you shim. The idea is to get the conrod in the middle of the crankcase mouth. Notes The crank must not touch the retaining plate. The other NF305 must have some end float clearance on it's rollers. Too much shimming on the left hand side will cause the right hand bearing to bind. You will have this problem without any shims if you use an Alpha bigend kit. We machine 0.5mm from the right hand cheek to allow for this when we use Alpha kits. Clearance is checked with the crank bolted up against the LJ7/8. (Mount the sprocket and rotor).

The best way to do this is with measurements, but not easy to do for most people. So lots of dummy builds until you get it right.

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beat
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Re: Building the crank into the casings B50 only

Post by beat » Fri Dec 18, 2009 8:40 pm

hi mark,
this means, mine is just buildet up this way ?
beat :roll:

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Re: Building the crank into the casings B50 only

Post by Norman_John » Wed May 26, 2010 10:48 pm

Hi there,
Does anyone have the process for a B44 bottom end?
Cheers
John

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Re: Building the crank into the casings B50 only

Post by kommando » Thu May 27, 2010 6:48 am

My process is as follows, note that it is not std so entails some risk.

1. Check removed bearing for markings, drive side should be C3, timing side ball could be C3 or C4.

2. Buy 2 NF305E bearings to match the fits of orginals, if there was a C4 on the timing side if you do step 3 then you can drop to C3 on that bearing. The E identifies the roller bearings as Extra capacity which Norton called superblend. The rollers are barrel shaped and the roller corners do not dig in.

3. Relieve crank main bearing journals so that the main bearing inner rings are a tight sliding fit.

4. Install frozen roller outers in hot crankcases.

5. Install crank in cases and button up.

6. Check end float, due to using 2 rollers with no ball interfering you will be able to move the crank in and out easily.

7. Install shims to limit end float to 3-5 thou and to put rod in center of cases.

Have done this mod to several engines so far with no problems, using 2 E rollers gives the B44 the same main bearing capacity of the B50 (unless you install 2 E's in a B50 :mrgreen: ) . The lack of the retention of a ball is not an issue, there are 10's of thousands of Norton twin engines running 2 rollers with no control of endfloat but shims. Both bearing inner rings are locked to the crank when the crankshaft end nuts are installed and torqued.

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Re: Building the crank into the casings B50 only

Post by b50root » Thu May 27, 2010 7:49 am

Nice Kommando.

This above is for B44??

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Re: Building the crank into the casings B50 only

Post by kommando » Thu May 27, 2010 8:39 pm

All pre B50's back to and including C15G/B40G, you just have to make sure you lock both bearing inners with the crankend nuts, think there was some early B25's with a washer missing that could be different.

Have also done it to a C15 with timing side bush (well fitted with a needle bearing from Alpha).

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Re: Building the crank into the casings B50 only

Post by Norman_John » Thu May 27, 2010 11:57 pm

Hi Kommando,
You make it sound so simple, thanks! I already had the crank bearing journals relieved by Alpha in order to make the fitting easier, and have a bag of various shims to suit.

Do you make any allowance for the thickness of the 'goo' used to seal the cases? What goo do you use? I have always used Wellseal in the past.

Cheers
John

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Re: Building the crank into the casings B50 only

Post by kommando » Fri May 28, 2010 8:45 am

Go for the tight side of 3-5 to cater for the goo, I use a Loctite anerobic goo, you put lots on and it only sets in the absense of air, any excess wipes off or if inside gets mixed with the oil as its still liquid.
Last edited by kommando on Fri May 28, 2010 5:35 pm, edited 1 time in total.

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Re: Building the crank into the casings B50 only

Post by rhino » Fri May 28, 2010 3:59 pm

kommando wrote:I use a Loctite anerobic goo
Is that the technical term for it >44

Do you have a code? sounds useful :thumb

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Re: Building the crank into the casings B50 only

Post by rhino » Fri May 28, 2010 5:01 pm


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Re: Building the crank into the casings B50 only

Post by kommando » Fri May 28, 2010 5:34 pm

I bought this, was a lot less as it was ex MOD stock which has a shorter declared shelf life and was out of date, still seems to work regardless

http://cgi.ebay.co.uk/LOCTITE-574-FLANG ... 3a5b20e51f


Here is the seller, but he currently does not have any listed

http://stores.ebay.co.uk/Loctite-Bargai ... ec0Q2em322

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