4350 pinch bolt

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1951 adam
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4350 pinch bolt

#1

Post by 1951 adam » Wed Aug 29, 2012 4:24 am

My parts books dont give me the size, or list this bolt at all.... but it is the number in the parts break down , Its the lower triple tree pinch bolt. The 41 to 84 book shows it as a 7/16 bolt, 55-and up, the cast number on my lower tree is a dash 48, and its a 7/16 20 thread. so I'm a little confused.....I orderd 4350's and they are a 3/8 corse bolt....did they change the tee in 55? The part number is omitted completly in the hardware section. it not even a prefexed part number on the lower tree, its a straight -48, any help much apreciated as always, Adam



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Re: 4350 pinch bolt

#2

Post by 1951 adam » Wed Aug 29, 2012 4:38 am

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Robert Luland
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Re: 4350 pinch bolt

#3

Post by Robert Luland » Wed Aug 29, 2012 10:48 am

Adam, if the brain is working this morning. There were three different bolts used over the years. I do not remember the particulars. Do yourself a favor and get a copy of an earlier manual. Bob L

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Re: 4350 pinch bolt

#4

Post by pan620 » Wed Aug 29, 2012 1:10 pm

My memory thinks..... 1949 3/8x24 with nut, 50-54 3/8-16, 54 up 7/16x20
Hope this helps.

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Re: 4350 pinch bolt

#5

Post by 1950Panhead » Wed Aug 29, 2012 1:32 pm

49 .375" fine stud with nut
50-54 .375" coarse bolt
55-57 7/16 fine bolt

Jerry

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Re: 4350 pinch bolt

#6

Post by Bosheff » Wed Aug 29, 2012 7:22 pm

If memory serves me, it should be a 7/16 fine thread bolt, probably hardened to some degree. I've never heard or seen a stud/nut set-up or a course thread bolt used for the pinch bolt to secure the fork tubes, but I may be incorrect....bosheff

1951 adam
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Re: 4350 pinch bolt

#7

Post by 1951 adam » Thu Aug 30, 2012 12:22 am

The concensus seems that I have a 55 style lower tree, I'm surprized that the part number was not updated to a -55 , Thanks for the input on this one, good stuff to know for sure, with bikes this old its hard to guess what happend thru the years.....might have been in an accident, or just put together with what was around, all part of the fun! Adam,...... I'll have to hunt down the correct number, my one book is a reprint up to 57, surprized it only offers the one part number...

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Re: 4350 pinch bolt

#8

Post by RUBONE » Thu Aug 30, 2012 1:42 am

Adam,
Many of the early trees were stripped from repeated tightening. The fix at the time was to drill them out, tap to 7/16ths, and run with it. I did a few myself! I may even have a service bulletin on it.
Original trees with 3/8ths holes in them are hard to find!
The first pair of trees I saw with studs in them I thought, "who did this goofy shit". It was later I found out they were correct!
Robbie

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Re: 4350 pinch bolt

#9

Post by FlatHeadSix » Thu Aug 30, 2012 2:52 am

I believe the 7/16 - 20 NF came along in '55, the hardware number for that one was 4638B, not 4350. I'm going from memory here too (not so good when you get to be an old man), but it seems to me that it originally came out in 1950 with the adjustable forks and then became standard in 1955 for all of them.

I may have some "reference" material out in the shop, I'll check tomorrow.
mike

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Re: 4350 pinch bolt

#10

Post by 1951 adam » Thu Aug 30, 2012 3:17 am

I just got the fork tubes together with the NOS springs, new seals, paper gaskets and nos lower nuts, the bushings are a nice fit, and the pre load with the springs feel perfect.....nothing like stock! just fits and feels right, I scored a nice set of NOS risers, and I got the rest of what I needed , caps ,hardware, bushings and those damn rubber washers 10 dollars each! waiting on the 49-59 timkens, then I can get her rolling and off the jack. Got so involved putting the forks together, I forgot to see my girlfriend!! Shes gonna be pissed....The things we do for our bikes. Thanks for all the great information ! Adam

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Re: 4350 pinch bolt

#11

Post by Limey_Dave » Sun Sep 02, 2012 12:40 am

The part number changed to 4570-48A not -55.
This is because the bolt thread doesn't prevent it fitting the earlier models.If they'd changed the size of the stem or something,it would have changed to -55.
It's common for parts to be changed four times,and end with a "D" on the end of the original number.
This is the problem with using later parts books,if you look in say a 1938 book,it will give a frame number for all VL's ending -36.
If your bike was a 31,what you did about the extra toolbox bracket,was your problem. :shock:

1951 adam
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Re: 4350 pinch bolt

#12

Post by 1951 adam » Mon Sep 03, 2012 6:18 am

Limey_Dave wrote:The part number changed to 4570-48A not -55.
This is because the bolt thread doesn't prevent it fitting the earlier models.If they'd changed the size of the stem or something,it would have changed to -55.
It's common for parts to be changed four times,and end with a "D" on the end of the original number.
This is the problem with using later parts books,if you look in say a 1938 book,it will give a frame number for all VL's ending -36.
If your bike was a 31,what you did about the extra toolbox bracket,was your problem. :shock:
Thank you Dave, I do understand that, but this is just a dash 48..... no letter prefix, thats what I dont get, did they even use prefix letters 60 years ago?

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Re: 4350 pinch bolt

#13

Post by RUBONE » Mon Sep 03, 2012 1:52 pm

Adam,
Keep in mind that casting numbers are not part numbers and sometimes the part has been changed but the original casting numbers are still used despite a machined difference that may only be reflected in part numbers. And also keep in mind that the letter suffix (not prefix) on part numbers goes way back , however they do not always denote an update, sometimes just a difference in finish, such as painted or chrome, or in the case of running lights a different lens color!
So the number on your tree does not automatically make it the earliest version!
Robbie

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Re: 4350 pinch bolt

#14

Post by 1951 adam » Mon Sep 03, 2012 5:44 pm

Robbie thanks for the info, It makes perfect sense now, I could have sworn I have seen suffix letters on cast parts, I might be thinking of actual part numbers, That I know are updated with a suffix, as always you are on point! thanks again , Adam

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Re: 4350 pinch bolt

#15

Post by RUBONE » Mon Sep 03, 2012 6:00 pm

Adam,
There can be suffix numbers on cast parts, but they don't change to denote a machining difference, they change when the mold is modified or changed. an example would be a K-Dodel cam cover as -52 and Sportster as -52A. Externally identical but different at the breather and front idler boss.
Robbie

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