Author Topic: In-line handlebar top triple tree / top yoke  (Read 2380 times)

Offline duTch

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Re: In-line handlebar top triple tree / top yoke
« Reply #15 on: 15.12. 2019 00:00 »
 
Quote
......OIF 1971->  ............ and does away with the BSA fork tube taper........

 You sure about that ?
 I bought my NOS Conical/OIF forks from the US and they have taper tops, as do any others I've seen- which isn't a lot

 I'll extra double check later though.....

Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline AnthonyA

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Re: In-line handlebar top triple tree / top yoke
« Reply #16 on: 15.12. 2019 00:57 »
Well Sluggo that's some crazy work. Mind-blowing actually, and the fact that back then they went all over the place. No wonder they went bankrupt haha !

I don't plan to use fork ears, as the standard headlight and its fairing will go away, replaced by a more discreet lamp with a smaller diameter, and no fairing. I find the whole thing very heavy looking (and simply heavy !).

Anyway, I'm kind of clueless now...
A10 Road Rocket (swing-arm)

Offline Swarfcut

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Re: In-line handlebar top triple tree / top yoke
« Reply #17 on: 15.12. 2019 09:48 »
Anthony. Have a look at Yamaha XS Series yokes. These have pinch bolts to suit plain tube legs and a more forward handlebar mount. Bit of a knife and fork job, but may be more to the style required. But as usual, a whole lot of extra work to mix and match.

Swarfy.

Offline duTch

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Re: In-line handlebar top triple tree / top yoke
« Reply #18 on: 15.12. 2019 10:45 »
 I dug my spare Comical/OIF yokes out;

 kinda ~'bout 6,3/4" between centres of tubes, Taper on top yoke= 1,3/8" (tube diameter) down to 1,14" over 3/4" thick
 Handlebar risers are rear of the tubes by about ~kinda 1/4' max, and ~kinda 'bout 40mm forward of the stem ** handy if you want to add higher risers

 incredibly over-precise measurements I know, but I wouldn't want to mislead anyone  *eek*

 Pic coming from phone sho®tly
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline RichardL

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Re: In-line handlebar top triple tree / top yoke
« Reply #19 on: 16.12. 2019 11:44 »
Thank you guys for the pictures and knowledge !

I don't mind cutting into the fork shrouds for them to fit, they're no concours parts anymore. I want to keep them though.

So, if I do this (top yoke A65 but stock bottom and steering + cutting into the shrouds), it will work ?
Cause I found one used online, and I don't know if I buy it or not...  *conf*

Anthony,

My A10 has the '62-'65  A50/A65 "moustache" top yoke with an A10 bottom yoke, so, width is correct. (The range of years is as close as I can tell from brief research.) I have headlight ears, not shrouds, and, yes, they are almost exactly 1" shorter than A10 ears. I also have A10 stanchions and they work just fine. I don't know if they are longer than A50/A65 for that yoke and don't really care. The story of why I have this combination is too tedious for this post. I've included some photos taken in a cramped space in my garage.

Richard L.

Offline AnthonyA

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Re: In-line handlebar top triple tree / top yoke
« Reply #20 on: 17.12. 2019 10:30 »
Thank you Richard, it looks perfect, this is exactly what I want to do !
Side note, the color of your bike is gorgeous, and the shape/size of the tank is what I'm looking for.
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Re: In-line handlebar top triple tree / top yoke
« Reply #21 on: 17.12. 2019 11:15 »
G'day Ant.
I doubt if you will be able to cut down your fork shrouds. The top is tapered to fit the staunchion, if shortened it will be very loose and the headlight ears will be too high. The ones on Richards bike look like early A50/65. 68-5059 and 68-5060.
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
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Offline RichardL

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Re: In-line handlebar top triple tree / top yoke
« Reply #22 on: 17.12. 2019 12:01 »
...and, yes, they are. Here is a quick shot at the story, now that I'm not thumb typing.

Bought the bike in '73 for $50. At the time it had an A50/A65 moustache top yoke, but I didn't know a damn thing about original parts. Put $3K of '70s money into having a shop restore the bike. In Novermber of '79, on my way home after a beautiful day at Malibu Beach, a kid made a left turn in front of a rather novice rider making a legal, but dumb, passage through a green light. After sitting in storage (mostly outside, the bike, not me) for 23 years, I decided to give restoration a try. Still not knowing anything about original parts, I bought A10 top and bottom yokes on eBay. I also pounded out some dents and had my headlight ears re-chromed. Lo and behold, my beautifully chromed headlight ears were not long enough when I went to reassemble the front end. After doing the research, I decided to buy a replacement A50/A65 top yoke rather than new ears and new chrome. Much cheaper, and faster to the finish.  Rebuild took around three years at my slow pace. Rode her around 60 miles before lack-o-sludge-trap-knowledge gave me another opportunity to rebuild the engine.

One thing you might notice with the A50/A65 yoke is the steering lock on centerline. A10 steering locks are off center. My answer was to attach a metal plate to the landing on the steering head where the A10 locking hole is found, then, make a new hole in the new plate. Works fine, since steering locks are just mild discouragers anyway.

Richard L.


Offline RichardL

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Re: In-line handlebar top triple tree / top yoke
« Reply #23 on: 17.12. 2019 12:04 »
One more thing, as if that wasn't long enough. Don't forget that not all A50/A65 top yokes were the "moustache" type with centered handlebars.

Richard L.

Offline AnthonyA

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Re: In-line handlebar top triple tree / top yoke
« Reply #24 on: 17.12. 2019 18:21 »
Tremendous help Richard !
And thanks for the story time, I always appreciate a little background.
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Offline Sluggo

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Re: In-line handlebar top triple tree / top yoke
« Reply #25 on: 20.12. 2019 00:58 »
I am sorry I was not more timely, I had surgery recently and really behind the curve, as well as an impending weather crisis now unfolding.  (lots of excuses) 

I went down and started doing photos and measurements.  I will hold off on the expansive "Comprehensive interchange and triple tree & Fork/stanchion ID" thread because I am not satisfied with the photos, lighting and need to do a better job of ID.  Admins have been generous in allowing Sticky Tech threads & worth doing properly so its useful.  I HAVE most every variation and some mystery ones to do it. But a crusty poorly photo illustrated one that jumps around the years is not helpful.

But to respond specifically The Mustache mid 60s trees would be your best bet. Its POSSIBLE you could use the 68-70 style Triumph ones that use P clamp risers, but not everything will line up.  I also photo'ed some of the ALLOY BSA B50 OIF variants and the 1971 and up Triumph-BSA OIF variants as well as the the T150/T160 and T140 Disc brake variants that ALSO use the P clamp risers.

I also did some surveys on fork tubes.  When I mentioned the taper, I slightly mis-spoke (The dangers of reliance on memory).  So heres the deal.

TAPER and Fork OD and Tree ID's vary.  SOME, but I am not sure which years but SOME BSAs used a stepped Tube OD and that presents problems in many ways.  REPOP tubes frequently  dont have that stepped OD.

Secondly, the tapers on the ends Differ.  On some early 60s BSA unit twin A65 forks I meaured the taper is gradual and then increases towards the end of the tube, but it appears the taper starts aprox 2" down,

But a 1971-72 BSA OIF tube no such long taper and it clearly is visible about 0.820 from the end and I would have to measure with a taper gauge or angle finder but its way different than pre 71 BSA.

The stems, also differ in length and in some cases the threads and OD.  The Mustache style stems seem to average around 7 & 5/8ths total from tree to top including lower bearing race.

The OIF stems are small in OD, approx 0.75-0.76 and the alloy trees for the BSA B50-B44-B25 have an odd threaded stem with fine thread at the top and a course thread THRU the bottoms.  Overall length total was  just a hair under 7" but from the tree to tip was 6". 

I also found 2 different thread forms to the tops of OIF stems, a medium course and a fine thread.

I have some pictures I will post tonight but, also keep in mind I need to recheck measurements because it was below freezing here, and my calipers were acting up.  **Approx.

More soon.
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Offline Sluggo

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Re: In-line handlebar top triple tree / top yoke
« Reply #26 on: 20.12. 2019 01:08 »
Better pictures coming as long as we dont lose power, Storm, its a' comin!

Mustache style trees, I will post up years and part numbers as well,. Got a long spread sheet and pages of notes.

Threads and land of Trees and parts current sorting.  *** IF ANYONE HAS ANY EARLY TRIUMPH TREES FOR A 48 AND 52 (pre-nacelle on the 48 AND nacelle on 52) i AM NEED OF SEVERAL SETS. TRADE OR CASH.
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Offline Sluggo

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Re: In-line handlebar top triple tree / top yoke
« Reply #27 on: 20.12. 2019 01:26 »
Alloy style typically used on BSA-Triumph scramblers. (Unit 500 twins Triumph hybrids, Unit Single B50s-B44-B25, *Note I have a late B50 that was sold and titled as a Triumph 500 single, sold in 1974 and have original receipt)

Land O' Trees and my current mess in storage. (Feel free to come by and lend a hand, There is a bar next door, Also all the coffee you can drink, and Mrs Sluggos cooking.)

Close up of Taper, I can do better, but thats what I could manage under the circumstances.

The Pre OIF unit single style trees. I *BELIEVE* but will confirm there is 3 variants of these but might be a viable option, They have a reverse lean for the cast in risers and might be an option. These were used on C15s, C25, B25, B40, B44, and the Triumph T25 variant. 
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