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Discussion Starter · #1 ·
Hi Everyone,
I’m helping out a friend getting his bike back on the road. 1964 T120R converted to a hard tail. The forks need work but I don’t know what they’re off of. If anyone could help identifying them it greatly help getting parts for them.
Thanks, Dan
757116
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Hi Dan,
1964 T120R
The sliders appear to be Triumph, assuming they're chromed steel and the chrome is pitted? If they are Triumph, they can usually be dated depending whether the spindle caps are secured by '70-on studs-'n'-nuts or pre-'70 bolts; if bolts, whether they're '69 UNF (24 threads per inch) or pre-'69 BSC (aka "CEI", 26 tpi). Another change is the internal damping parts changed '68-on.

The chromed covers above the sliders to the top yoke aren't Triumph (or anything British?). I have it in mind the headlamp/mounting is Bates or another US custom parts maker? There also appears to be some sort of aftermarket cover over the top of the top yoke? Hopefully @KADUTZ will see this thread and chime in.

While the brake is '69-on, it was actually used up to '74 on the T100; likewise similar sliders if they're Triumph.

Because of the protrusion of the spindle outside the slider, I suspect the yokes are either contemporary with the "1964" or at least pre-'69 - '69-on, Triumph changed the yokes to space fork legs 1/4" further apart - I suspect the spindle's a longer '69-on one.

Hth.

Regards,
 

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@Stuart

The following will be on the assumption that (other than the headlamp, its mounting bracket, and the fork shrouds) parts used were Triumph. The previously mentioned parts were Kustom parts available over the counter during the 60's and 70's. I think it is safe to assume this machine was modified during or after 1969 due to the front wheel

While I will be repeating some of the statements above the brake hub is 69 or later TLS..

As far as the steering yoke lugs or trees (call them as you wish) I suspect they may be original. This can possibly be determined by measuring them and looking at the casting number (if it wasn't ground away by the plater year's ago).

Regarding the fork tube assemblies they appear to be triumph you will not really know what you need until you take them apart. They could be the original 1964 pieces. The seal cup was the same from 64-68 (97-1654)and all used seal 97-1500. Fork tubes used in 1964 (97-1649) were a different part number from 65-67 (97-1889). But I believe most of the other internal parts were the same 64-67.

As far as the sliders they appear to be missing the fender boss by the spindle/axle cap. I suspect their removal was part of the Kustomizing process. I am going to date them between 1964 and 1967 inclusive.(1964 used 97-1650/1651 and 65 thru 67 used 97-1842/1843) The axle spindle caps (97-1053) were first used in 1957 The retention bolts (97-1070) would be a CEI thread.

What Dberto needs to do is take the front end apart and match up items to what is shown in various years parts books online

K . 😷
 

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Discussion Starter · #8 ·
Hi Dan,

The sliders appear to be Triumph, assuming they're chromed steel and the chrome is pitted? If they are Triumph, they can usually be dated depending whether the spindle caps are secured by '70-on studs-'n'-nuts or pre-'70 bolts; if bolts, whether they're '69 UNF (24 threads per inch) or pre-'69 BSC (aka "CEI", 26 tpi). Another change is the internal damping parts changed '68-on.

The chromed covers above the sliders to the top yoke aren't Triumph (or anything British?). I have it in mind the headlamp/mounting is Bates or another US custom parts maker? There also appears to be some sort of aftermarket cover over the top of the top yoke? Hopefully @KADUTZ will see this thread and chime in.

While the brake is '69-on, it was actually used up to '74 on the T100; likewise similar sliders if they're Triumph.

Because of the protrusion of the spindle outside the slider, I suspect the yokes are either contemporary with the "1964" or at least pre-'69 - '69-on, Triumph changed the yokes to space fork legs 1/4" further apart - I suspect the spindle's a longer '69-on one.

Hth.

Regards,
Thanks Stuart,
From what I’m learning I think the front wheel is 69 or 70. The forks I don’t know much about. From the information from yourself and KADUTZ the sliders are probably original and modified. The forks have absolutely no dampening and will need all new seals and maybe new springs. Luckily there’s a British Bike shop close by that reopened a couple of years ago that sells reproduction parts and still has some original stuff so I’m lucky to have a place to match parts.
Looks like I have a idea what I’m working on now. Thanks for Your Help,
Dan
 

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Discussion Starter · #9 ·
@Stuart

The following will be on the assumption that (other than the headlamp, its mounting bracket, and the fork shrouds) parts used were Triumph. The previously mentioned parts were Kustom parts available over the counter during the 60's and 70's. I think it is safe to assume this machine was modified during or after 1969 due to the front wheel

While I will be repeating some of the statements above the brake hub is 69 or later TLS..

As far as the steering yoke lugs or trees (call them as you wish) I suspect they may be original. This can possibly be determined by measuring them and looking at the casting number (if it wasn't ground away by the plater year's ago).

Regarding the fork tube assemblies they appear to be triumph you will not really know what you need until you take them apart. They could be the original 1964 pieces. The seal cup was the same from 64-68 (97-1654)and all used seal 97-1500. Fork tubes used in 1964 (97-1649) were a different part number from 65-67 (97-1889). But I believe most of the other internal parts were the same 64-67.

As far as the sliders they appear to be missing the fender boss by the spindle/axle cap. I suspect their removal was part of the Kustomizing process. I am going to date them between 1964 and 1967 inclusive.(1964 used 97-1650/1651 and 65 thru 67 used 97-1842/1843) The axle spindle caps (97-1053) were first used in 1957 The retention bolts (97-1070) would be a CEI thread.

What Dberto needs to do is take the front end apart and match up items to what is shown in various years parts books online

K . 😷
Thanks KADUTZ,

My experience with Triumphs is limited and I’m learning lots. This is the third Bonneville I’ve worked on. 1973 T140V, 1977 T140V and the 1964 T120R. Also a 2006 t100.
The Part numbers are a big help but I think you’re right I’ll need to take the forks apart and match the parts. Luckily there’s shop close by that sells reproduction parts and has some original parts so I have a place to match
The information I’ve received from yourself and StuartMac is a great help.
Thanks, Dan
 

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Hi Dan,
think the front wheel is 69 or 70.
Mmmm ... Triumph did more evolution than revolution, so many parts can either be - or appear to be - compatible:-

. If the brake plate is 8", it's '69-'74; if it's 7", it's '69-'71.

. It's likely the spindle and brake plate centre nut are contemporary with the brake plate. If it turns out the fork legs are the pre-'69 6-1/2" centre-to-centre, and you're replacing the wheel bearings, the '69-on spindle-'n'-nut can be replaced with the shorter pre-'69 bits at the same time? (y)

. The brake plate/shoes will fit in any Triumph drum of the correct diameter; however, if 8", Triumph changed the drum at least three times during the 1960's; images taken from each side between your previous two (i.e. at 45 degrees to the line of the wheel or the spindle) showing the spokes into the drum will identify which version you're dealing with.

Forks
sliders are probably original and modified.
Please confirm whether the sliders are aluminium alloy or chromed steel, the horizontal centre-to-centre distance between the legs. In what way are the sliders modified?

absolutely no dampening
As I posted earlier, the internal damping parts changed '68-on; it's possible the original builder struggled to connect say, '64 stanchions with '68-on sliders so simply left out the internals?

will need all new seals and maybe new springs.
Imho, maybe strip them down, photograph what you find and post the images here? Posters here can tell you both if anything's wrong and if anything's missing.

Don't bank on repro. parts being or fitting together better; there are (y) parts, but there's plenty of crap too. (n)

In addition to new seals and springs. new stanchions also might be wise - they can bend just under the bottom yoke even if the bike hasn't been involved in an accident. They can be rolled straight but Triumph hard-chromed stanchions '70-on and the pattern part makers seem to have adopted this for all stanchions, (y) but struggle to maintain dimensions ... :rolleyes: Thread not long ago about replacement springs, the OP found difficulty buying two new the same length ... you might need to cough up extra for a pair of Progressive Suspension's. :rolleyes: Etc., etc.

Stanchion and spring dimensions are in the workshop manual; parts books can be read here, click on the one(s) required. The forks' (the bike's) fasteners are pretty-much guaranteed to be a mixture of British Standard (incorrectly-called "Whitworth" by many of your countrymen ...) and Unified threads; if you don't have screwpitch gauges already, consider getting a set?

Hth.

Regards,
 

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Thanks KADUTZ,

My experience with Triumphs is limited and I’m learning lots. This is the third Bonneville I’ve worked on. 1973 T140V, 1977 T140V and the 1964 T120R. Also a 2006 t100.
The Part numbers are a big help but I think you’re right I’ll need to take the forks apart and match the parts. Luckily there’s shop close by that sells reproduction parts and has some original parts so I have a place to match
The information I’ve received from yourself and StuartMac is a great help.
Thanks, Dan
Dan

www.vintagebikemagazine.com has printable parts books pages take a look over there your time spent reviewing the books will be time well spent. Stick with the 64-67 books (my opinion) for the fork parts Also review the manual Stuart posted it is written in English not quite the same as it is spoken over here.

Once you get the tube/slider assembly out of the machine you will want to remove the seal cups. These unscrew from the lower member (slider). While a special tool is available they can be loosened using a piece of old inner tube, a hose clamp (like on your cars radiator), hammer and your blue vise. Wrap the cup with the inner tube and snug down the clamp over it. The hex of the clamp screw facing so it will take the blow from the hammer as it it hit to unscrew the cup. I have seen pipe wrenches used also but they tend to tear up the cup.

Your comment on the forks having no dampening makes me wonder if the bike had a internal fork spring conversion done with a few slugs added to restrict movement. When I first saw your pictures I wondered how that front suspension worked. with the covers as low as they are. One last item and to more or less repeat Stuart the sliders are dirty chrome and not aluminum correct. Once you get the forks post some pictures so we know for sure what you have

K 😷
 

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Discussion Starter · #12 ·
Hi Dan,

Mmmm ... Triumph did more evolution than revolution, so many parts can either be - or appear to be - compatible:-

. If the brake plate is 8", it's '69-'74; if it's 7", it's '69-'71.

. It's likely the spindle and brake plate centre nut are contemporary with the brake plate. If it turns out the fork legs are the pre-'69 6-1/2" centre-to-centre, and you're replacing the wheel bearings, the '69-on spindle-'n'-nut can be replaced with the shorter pre-'69 bits at the same time? (y)

. The brake plate/shoes will fit in any Triumph drum of the correct diameter; however, if 8", Triumph changed the drum at least three times during the 1960's; images taken from each side between your previous two (i.e. at 45 degrees to the line of the wheel or the spindle) showing the spokes into the drum will identify which version you're dealing with.

Forks

Please confirm whether the sliders are aluminium alloy or chromed steel, the horizontal centre-to-centre distance between the legs. In what way are the sliders modified?


As I posted earlier, the internal damping parts changed '68-on; it's possible the original builder struggled to connect say, '64 stanchions with '68-on sliders so simply left out the internals?


Imho, maybe strip them down, photograph what you find and post the images here? Posters here can tell you both if anything's wrong and if anything's missing.

Don't bank on repro. parts being or fitting together better; there are (y) parts, but there's plenty of crap too. (n)

In addition to new seals and springs. new stanchions also might be wise - they can bend just under the bottom yoke even if the bike hasn't been involved in an accident. They can be rolled straight but Triumph hard-chromed stanchions '70-on and the pattern part makers seem to have adopted this for all stanchions, (y) but struggle to maintain dimensions ... :rolleyes: Thread not long ago about replacement springs, the OP found difficulty buying two new the same length ... you might need to cough up extra for a pair of Progressive Suspension's. :rolleyes: Etc., etc.

Stanchion and spring dimensions are in the workshop manual; parts books can be read here, click on the one(s) required. The forks' (the bike's) fasteners are pretty-much guaranteed to be a mixture of British Standard (incorrectly-called "Whitworth" by many of your countrymen ...) and Unified threads; if you don't have screwpitch gauges already, consider getting a set?

Hth.

Regards,
Hi Stuart,
The sliders are chromed steel. Measuring the distance between the sliders ta the axle caps is 6 1/2” if this is the correct place to measure. The modifications the stanchions I mentioned was actually modified sliders, the chroming and the fende brace mounts. The left side the mount is actually there. The right side appears to be broken off.
Thanks for the links to the work shop manuals! Will be a great help.
Working on the 77 t140 I learned about after market parts quality and seems like LH Harris makes good quality parts,
Working on vintage Triumphs was not something I planned on doing but they are finding me and I enjoy working on them. Having a forum like Triumph Rat that puts me in contact with people like you and KADUTZ is a great help. Hope sometime I’m able to be of help also.

Thanks, Dan
 

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For what it's worth those sliders were fired 64-65 only. They have a cast bottom lug for the axle instead of the machined one used 66 onwards.
 

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Hi Dan, Rod,
sliders are chromed steel.
those sliders were fired 64-65 only. They have a cast bottom lug for the axle instead of the machined one used 66 onwards.
Thanks, guys.

Rod: possibly just for my information, by "bottom lug", you mean the bit between the tube of the slider and the spindle, or the bolt-on bit below the spindle?

Measuring the distance between the sliders ta the axle caps is 6 1/2” if this is the correct place to measure.
You were measuring between the centrelines of each leg, not between the inner faces of the axle caps? Given there's only 1/4" difference between 'later' ('69-on) and 'earlier' (pre-'69), if judging the centrelines of the the fork legs accurately is difficult, measure between the centres of the big hex. heads, one at the top of each fork leg?

Hth.

Regards,
 

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Hi Stuart,

By lug ( For want of a better word ) I mean the part below the bottom of the tube but also in this case the cap. If you enlarge the pic and compare it to the same part on your T100 fork tube you will see both the lug and cap are completely different from the more common 66-70 design.
 
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