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  1. #1

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    Default Ron finch springer help

    Recently picked up a 10ish over finch springer to go on my cb750 build. Its a GME frame i believe. neck is 7in and ID is right under 2in. Stem on the springer is way short and ill be having a new stem machined. I got a few questions since this is the first time ever dealing with non stock steering stuff. For the stem, i have it made 1 in through out the whole length correct? and what should the length of the stem be? tried finding measurements for it and had no luck. and i also need a bearing adjuster nut and a stem nut i believe. could someone point me in the direction of the adjuster nut, stem nut, and what races and bearing i need? been digging though forms and having trouble finding answers.
    Attached Thumbnails Attached Thumbnails bike 1.jpg   springer 2 (1).jpg   springer 2 (2).jpg  

  2. #2
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    I believe that is an Amen frame, probably once a Savior plunger, that got hacked off and a pointed hardtail welded on -
    I can see what looks to be some welds where the plunger box would have been; see Amen Savior for Honda 750 here, note neck, seat area, and side seatposts at 90 to top frame rail, and rear engine plates...your front engine mounts same as factory ad?:
    Click image for larger version. 

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    You have bearing races in that frame neck now? if so, what are the numbers on top and bottom one?
    If not, what are bearing race bore measurements - to the thousandths of an inch - use a vernier, dial or digital...need to be more precise than, "right under 2in". Measure OD of races too and record that info.

    Get a set of tapered roller bearings (commonly referred to as Timken - a major manufacturer), with OD of race to fit your neck, and ID of bearing to fit the neck; 1.000"

    You want a top nut and crown nut with spigots to fit tight inside the bore of the top tree, with 1" x 24 TPI to be standardized with typical HD stuff, so easier to find. What is ID of bore through the top tree?
    Click image for larger version. 

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    to measure for neckpost length, install top and bottom bearings, measure and record overall length from top of top bearing to bottom of bottom bearing.
    add thickness of both top and bottom bearing dust covers.
    Add length of top nut from bottom of nut to base of spigot.
    add thickness of top tree.
    add amount for crown nut, from base of spigot to about 1/8 to 1/4" less than full thread depth.

    For the bottom below the bottom bearing, it depends on how it is secured in the bottom tree - press fit with a set screw and shoulder on the bottom, press fit with nut on bottom, or welded...thickness of bottom tree is a determining factor.

    The neckpost can be relieved between upper and lower bearing fits, to allow easier installation of the press fit bottom bearing. The upper bearing is a sliding fit, size-on-size.

    A couple drawings I did to help show:

    Springer upper bearing assembly
    Click image for larger version. 

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    Springer neckpost drawing:
    Click image for larger version. 

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    As those springers do not have a full lower spring seat attaching the two front legs together at the top, the axle is taking the full load to prevent the wheel from rocking side to side...check for rocker axle hole wear, that axle is a tight fit in each rocker, and the rocker studs are a tight fit in their rocker bores as well. Get new wheel bearings - looks like a Hallcraft small brake wheel.
    That assembly could benefit from a springer top spring stabilizer ; see one example - can just be flat:
    Click image for larger version. 

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    Thread: springer
    http://www.chopcult.com/forum/showthread.php?t=51537

    Thread: 7/8" stem convert to 1" (Amen frame)
    http://www.chopcult.com/forum/showthread.php?t=55511

    some springer parts here:

    http://www.bitterendchoppers.com/SpringerParts.html

    https://paughcoparts.com/products/fo...and-sportsters

    https://www.paughco.com/2008-catalog...-springers.pdf

  3. #3
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    could also just extend the neckpost you have by slugging it; adding a section in the middle, like a CC member did here:

    Click image for larger version. 

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    Click image for larger version. 

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    Click image for larger version. 

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  4. #4

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    Thanks a ton for that response, much more info then i was expecting. When and got some digital calipers this morning, got of the springer off the frame, and pulled the bottom race out (no top race was in). also definitely seems that you are right about it being an amen with welded on plates. hard to tell if there are welds there with the paint on it but im gunna get it sandblasted eventually before i fix some issues with it so should be able to see better then.

    Measurement for race seat on top of neck is 1.9025
    Bottom of neck is 1.9585
    OD of bottom race (number L44610, Bower) is 1.99709
    and bore in top clamp is 1.3210

    Stem has a set screw and seems to be pressed in from the top. Im gunna disassemble the springer possible tonight to remove the bottom tree and see if i can get the stem out. if not ill run it down to the machine shop on monday and have my dads buddy remove it.

    I do have a question on how to remove those top spring nuts. not really sure how to go about that.
    also is there anything that should be replaced or inspected while i have it apart? I looks like i might have to replace the 2 smaller inner rebound springs
    Click image for larger version. 

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    also will definitely put one of those top spring stabilizers on. great idea.

  5. #5
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    Why not ask Ron Finch ?
    He's still around.

  6. #6

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    got it figured out. got the springer disassembled tonight. figure i should be able to find out what the bushing tolerances should be by digging through the forms. everything looks fairly good though. Also pretty sure this (https://www.lowbrowcustoms.com/produ...g-and-race-set) is the correct bearing i need after going through the timken bearing catalog. I do have one question about the stem still that i need an answer too. does the bottom of the stem need to be stepped at all for the bearing to be firmly pressed on or can it just be 1 in all the way through the stem?

  7. #7
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    This article shows springer maintenance, and using a ratchet strap to compress springs for removal & assembly:

    Springer 101: Routine Springer Maintenance

    Click image for larger version. 

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    https://cyclesource.com/springer-101...r-maintenance/


    In one of the ChopCult links above, it shows setting up side clearance for the rockers at 0.002" to allow movement, but not bind.
    Use shims to get the proper clearance for rocker side clearance.

    I do have one question about the stem still that i need an answer too. does the bottom of the stem need to be stepped at all for the bearing to be firmly pressed on or can it just be 1 in all the way through the stem?
    Look at the 2nd drawing I did above - it shows that the neckpost has a section between the upper and lower bearing machined locations that is machined (non-precision) to be less than the bearing ID to allow easier bottom bearing installation. The bottom bearing should be a 1 thou press fit on the stem.

    Original ad for Finch - note comment about special bushings;
    Click image for larger version. 

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    Measurement for race seat on top of neck is 1.9025
    1.9025"= 48.3235mm

    Bottom of neck is 1.9585
    OD of bottom race (number L44610, Bower) is 1.99709
    1.9585" = 49.7459mm
    and
    1.99709" = 50.726mm
    Better re-check those measurements as you have the bearing race 38 thou, almost 1mm, larger than the neck bore

    and re-check your measurement for the L44610 bearing race, as it is 1.980" (50.292mm) OD:

    "1.980" OD Bearing Race/Cup #L44610"
    https://www.pacifictrailers.com/prod...44649-bearings

    Stock Honda CB750 steering bearing dimensions are 48.5mm and 50mm OD, top and bottom:

    CB750 (1969-'78)
    upper bearing: 26mm x 48.5mm (48.5mm = 1.909" )
    lower bearing: 30mm x 50mm (50mm = 1.9685" )
    CB750 (1980 -'82): upper:26 x 47 and lower: 30 x 55

    Japanese Bike Steering Stem Bearing Sizes
    https://www.dotheton.com/index.php?t...es-list.20951/

    So not sure again about your measurements.

    That bearing set you linked to in the Lowbrow site is factory HD part number 48300-60;
    dimensions are 25.4mm ID x 50.3mm OD, and height outer race: 10.65 mm, height inner race: 14.8 mm
    https://www.wwag.com/cgi-bin/WebObje...ge=%21WW1378#0

    that one will work for the bottom if the L44610 was a good fit in there, but your measurements show the upper OD about 78 thou smaller...

    Confirm that your new digital calipers are measuring properly - measure that bottom bearing race to confirm the 1.980" measurement...adjust as required, then re-check your measurements.

    read the relevant info in those chopcult links above again too.

    You can reach out to Ron Finch here:

    http://www.finchscustoms.com/
    and
    Ron Finch ( Finch's Custom Cycles)
    https://www.facebook.com/Ron-Finch-F...2952548402143/
    Attached Thumbnails Attached Thumbnails finch double spring springer, view from top.jpg  

  8. #8

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    ok finally got a chance go check the measurements again.
    I also noticed that depending on if the caliper was in line with the backbone or not the measurement was considerably different so i got both.
    top
    in line with backbone 1.9390 in, 48.9966 mm
    Across backbone 1.9025 in, 48.3232 mm

    Bottom
    in line with backbone 1.9855 in, 50.4317 mm
    across backbone 1.9640 in, 49.8856 mm

    I used that race to make sure the caliper was reading right so it should be pretty accurate now.
    My understanding is that these amen frame (pretty sure this is an amen frame after looking at old ads, the mounts, seat angle, neck ect. all seem to be the same as the ads) came with either a harley or a honda style neck, taking the bearing that corresponded with the neck. The neck overall length is 6 15/16 in. I assumed that this meant it was a Harley style neck, because it seems that the honda style necks were 7.5 in. the races seems to be closer in measurement to the Honda measurements though.

    Looking though the Timken bearing catalog has left me fairly confused on what bearing to be running. i have read though those posts and a ton of others other other sites trying to find someone who had a similar neck to mine but haven't been able to find anything that was similar. also rechecked the bore on the top clamp and got 1.3270 in (33.7058 mm). I also cant seem to find what crown nut would work for this bore and all the crown nuts i find do not have the measurements, just what type of springer they were made for. tried finding what the bore measurements were for various top clamps but also came up empty handed with those searches. as you can probably tell this is my first time really messing with steering stem stuff so i really do appreciate the help so far.

  9. #9
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    looks like the neck frame tube is a bit out-of-round by about 0.020"

    Based on the average of your measurements of 48.660 mm top, and 50.159 mm bottom, looks like a Honda neck at 48.5 and 50 mm; both about .16 mm (0.006") over standard factory measurement.

    CB750 (1969-'78):
    upper bearing: 26mm x 48.5mm (48.5mm = 1.909" )
    lower bearing: 30mm x 50mm (50mm = 1.9685" )


    The neck overall length is 6 15/16 in.
    Harley neck at 7-1/16":
    Click image for larger version. 

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    Stock CB750 frame was 7.46" long:
    Click image for larger version. 

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    The bearings would be tapered roller replacement with races for Honda CB750; 1969 - 1978; and bearings with 1" ID for your springer neck.

    The typical bore through the center hole of the top tree to match the spigots on the top nut and crown nut, as found on Jammer, Paughco, DNA, midUSA, others, is 1-1/4" (1.250"):
    look at drawing here:
    https://www.jockeyjournal.com/forum/...ad.php?t=99702

    You measured that bore at 1.327"...that may be why there is a sleeve in the top in this Finch springer pic:
    Click image for larger version. 

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    Tapered roller replacement bearings:

    Honda CB750 Neck Bearings

    Safety is just as important as looks. Ever drive a bike with bad neck bearings? Not fun!
    This tapered neck bearing set will give you support that OEM ball bearings never had.
    With people changing neck angles, this bearing set is even more important!
    Fits 1969-1978 SOHC
    FR-034 $39.95
    http://www.cyclexchange.net/frame__end.htm

    Will need to drop in L44643 tapered bearings with 1" ID to match your springer neck.
    Can use utility trailer bearings:
    https://www.etrailer.com/Trailer-Bea...er/L44643.html

  10. #10

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    awesome man, ill order those then. Didn't realize you could run the 750 races and drop in different bearings. I appreciate the help a ton. Once i got the bearings and nuts ill get the measurements and get that stem made up. Ill post a picture in here once its all done. Thank you for the help, you have be way more helpful then i could have imagined.

  11. #11

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    Click image for larger version. 

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    Got the Stem made up, bearings and races in, and got the springer all mounted up. Very happy with the stance now. got a bit more work on the springer but gunna put that off till later in the build. thank you for all the help.

  12. #12
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    That looks so good. well done.
    Can you share some details on what you used for bearings, how you made the neck, and the modifications needed to get it all together...it might help the next guy.

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