[dhowlan]

I realized there hasn't been a photo lately.

 

[Andytheflyer]

Interesting to see those US spec bars - they are high up, and the different rear light housing. All you need now is a front mud fender. Looking good to go.

 

[StuartMac]

Hi Andy,

US spec bars - they are high up,

Fwiw, not really, it's partially the angle of the photo. and partially they're a little higher on the '69 top yoke, which has the 'bars mounting cast on, rather than the rubber-mounted eyebolts on your bike. I have the same 'bars on my T100 and T150 with rubber-mounted eyebolts, I hate the shape of the late-1960's-on "UK" 'bars, particularly with the standard footrests position.

Hth.

Regards,

 

[Andytheflyer]

Hi Stuart - now that's interesting. My 72 UK&GE came with the cast in mounting top yoke, as shown in the 72 parts book. However, in the baskets of bits I bought, there was a top and bottom yoke, with the bottom yoke having a parts label 97-4501, so a T100 bottom yoke. The 'spare' top yoke has the rubber inserts, but no parts label. I fitted the cast-in mount top yoke - but I have the rubber inserts top yoke in the shed. Looks like I should swap the top yokes. The boxes of bits did not include the handlebar P clips, which is why I thought that the cast in mount is correct - but maybe not.

 

[StuartMac]

Hi Andy,

My 72 UK&GE came with the cast in mounting top yoke,
However, in the baskets of bits I bought, there was a top and bottom yoke, with the bottom yoke having a parts label 97-4501, so a T100 bottom yoke. The 'spare' top yoke has the rubber inserts,

My T100 has a rubber-mounted-eyebolts top yoke because it has a disc-brake front end - a mixture of T150V and OIF bits, T150V yokes because, essentially, all dry-frames use the same bits.

Your spare top yoke will fit your bike if it has the threaded holes to mount speedo. 'n' tacho., the stanchion holes are 6-3/4" centres and tapered internally. The other three variants are:-

. pre-'69 if otherwise the same but stanchion holes are only 6-1/2" centres;

. conical hub if it lacks threaded holes to mount speedo. 'n' tacho. but does have the two extra holes to rubber-mount the ends of the thick wire headlamp brackets;

. disc-brake if the stanchion holes are 7-5/8" centres and parallel.

cast in mounting top yoke, as shown in the 72 parts book.
The boxes of bits did not include the handlebar P clips, which is why I thought that the cast in mount is correct

Both top yoke types were available in '72 and either could be fitted easily, so original ("correct") was more-likely whatever Meriden had and/or whatever the original buyer wanted? As you have both yokes, try the rubber-mounted eyebolts and see how you like them? Only real issue is the quality of the Metalastik bushes; buy from a reputable dealer and hopefully you shouldn't get 'floppy' ones ...

A couple of details to bear in mind with those pre-'73 'US' bars:-

. There are at least two versions (discounting the confusingly-various part numbers ) - pre-'71 and '71/'72, the former has two small (threaded?) holes in the left 'bar for mounting the corresponding horn/dipswitch.

. The T100R 'bars are wide; my T100 having later switch clusters, I lop about an inch off each end, reducing the overall width to about 29"; with a drum-brake lever, I think @triumpt120rv has lopped a bit more off his bike's?

Hth.

Regards,

 

[Andytheflyer]

Hi Andy,
Your spare top yoke will fit your bike if it has the threaded holes to mount speedo. 'n' tacho., the stanchion holes are 6-3/4" centres and tapered internally.

The T100R 'bars are wide; my T100 having later switch clusters, I lop about an inch off each end, reducing the overall width to about 29"

Thx Stuart - I'd been wondering for a year what the spare set of yokes fitted. The stanchion spacing is indeed 6 3/4, and the top one has the threaded instrument bracket mounting holes. The Metalastik bushes are installed, but seem solid. I'd have to change them - and I've been round the floppy bushes circus on my TR7RV. It was hard to find the stiffer ones though, but they are way better.

The bars that came in the 'kit' were beyond recovery so I have pattern ones - these are 27" end to end, so OK for me.

Looking at the spare yokes closely, I reckon they are NOS, or maybe if they date from 1982 when the bike was dismantled, they would have been just NS. They've never been fitted onto stanchions. They just need a wash and brush up and they'd be fine. Top yoke has a p/n of 97-3667 cast into the part. Could be a winter project to fit them and the P mounts.

Thx for solving the mystery - I suspect a PO (and there have effectively only been 2) must have decided to change the top yoke when he stripped the bike, but the plan was never completed.

 

[StuartMac]

Hi Andy,

With apologies to Daryl for hijacking his thread ... 😔

spare set of yokes
Metalastik bushes are installed, but seem solid. I'd have to change them

Mmmm ... bear in mind there's a lot of leverage when 'bars and eyebolts are installed and everything's tightened up ... before condemning what might be perfectly-good bushes, imho build up the necessary, tap the yoke on to the stanchion tapers and heave the 'bars about a bit?

reckon they are NOS, or maybe if they date from 1982 when the bike was dismantled, they would have been just NS. They've never been fitted onto stanchions.
Top yoke has a p/n of 97-3667 cast into the part.

They're NOS - '69 was the first year of the 6-3/4"-centres forks; if you look in the parts books, "H3667" is the top yoke so they weren't cast any earlier than 1968 nor later than 1973. "97-3667" might indicate a later casting but, if it was cast at, or commissioned from an outside caster by Small Heath, they'd have used the all-numeric format even in 1968.

No reason for your yokes to be cast in the 1980's - the Co-op was around in the early 1980's plus there was stacks of NOS bits then; had the Meriden workers not thrown the toys out of the pram in September 1973, certainly the next bikes down the line would've been a batch of TR5T's, for which the parts were ready over the road in the Meriden No.2 factory. The workers never occupied this and iirc that's where Matt Holder went with his Aerco Jig & Tool, although I don't know whether he bought all the spares or NVT sold off some.

Bear in mind too, in the 1980's, dry-frame 650's were only just starting to be appreciated; there were plenty to go 'round but soon people started hauling container-loads back from the US. There wasn't much interest at all in 500's - the basics of my T100 were assembled around 1985 and, bar the crankcases (which were reimported from the US just as an engine) for the number, it was pretty-much all brand-new parts. Even in the early naughties, when I had enough spare cash to buy the standard front end bits to put in a box against the day I might want to sell the bike, a lot of them were still NOS ... although iirc, I was relieved of forty quid by Yeomans for a used 8" TLS and hub.

Hth.

Regards,

 

[dhowlan]

See! I knew a picture would be a good idea.

With apologies to Daryl for hijacking his thread ... 😔

Lol. No problem. More data!

 

[Andytheflyer]

Hi Daryl, apologies! But that photo solved a conundrum for me, so many thx.

 

[dhowlan]

Out of curiosity, I measured the bars. 28-1/4" tip to tip including grips. Rise is about 5".

 

[Andytheflyer]

They just looked to be very high to me - I have a Canadian import TR7RV with the US spec bars (which I like on the torquey 750 as it's a relaxing ride and I sit up more than on my T100R) so I'm used to them, but mine don't look anything like as high as yours, but maybe I have mine rotated back a bit more. Must be the photo.

 

[StuartMac]

Hi Daryl,

Out of curiosity, I measured the bars. 28-1/4" tip to tip including grips. Rise is about 5".

Intriguing ...

The two sites I know of with 'bar dimensions on images are BCS's and Baxter's; regrettably, neither has the specific '69 US-market T100's 97-1873 listed (Baxter links it to 97-4252 but I know that's '71/'72 as it doesn't have the holes for the standard '69 horn/dipswitch).

97-1870 is listed for '69 US-market 650's, but that's one with 97-1511 and the aforementioned 97-4252 that are all similar dimensions. Another snag with those sites is they both did the measuring on pattern 'bars - e.g. having owned a T160 from brand-new, the BCS 97-4651 dimensions aren't quite the same as I measure ...

From your dimensions, in lopping off a inch or so from each end of a 97-4252, I wonder if I've ended up close to original '69 US T100 97-1873?

Thanks for adding the info.

Regards,

 

[dhowlan]

It's been a while huh? I'm not sure when I can call it done, but I must be close. I'm starting to assume that it will work.

I think I mentioned the speedometer at some point and I wanted to throw in a few comments in the hopes it might help someone else. When I got the bike, the speedo cable was broken. The PO did not remember that happening. My current theory is that it broke because the speedo head seized and then even pushing the bike was too much for the cable.

As a result of that, I disassembled the speedometer. I learned a lot from that. I can say the author of the book on the subject was very helpful assisting me even beyond the info in the book. However, my latest interaction with a gauge, the tachometer, has given me some insight as to whether disassembling the speedometer was necessary. The tachometer worked fine. For a while. Then it started getting twitchy, like catch and release. Unfortunately, before I got to disconnecting it, it also snapped. The shaft in the tach was seized. As I didn't really enjoy taking the speedo apart just to clean and lubricate the shaft, I decided to try to free it up without taking it apart. If worse came to worse, not much to lose.

I started with a mix of atf and kerosene. I tried to keep the fluid just on the shaft by just setting the whole thing in a pan filled just high enough to soak the shaft area. This eventually resulted in some hand/allen wrench turning of the shaft being possible. Turning the shaft felt like what I can only imagine was dried up lube causing friction. It would turn, but not uniformly. After several weeks of slow improvement, I switched from that to Silkroil. I just kept spraying the base and then spinning the shaft slowly with a drill. I'd spray, spin, spray, then let it set for a day. I probably did that for a month. Eventually, it seemed like it got to a place of no progress. Then I increased the spin time to a minute vs 5-10 seconds. Then I increased it to two minutes. The tach was reading about 6k while the drill was spinning. After a couple of weeks of that, the shaft felt pretty good. My bar for "good enough" was could I turn it by using just my bare fingers. So, new cable installed, and so far so good. Fingers crossed that this remains the case for a long time. What this all means is that it may have been a workable path for the speedometer that would not have required disassembly. If the tach binds up again, I'll let y'all know.

Unrelated to all that, but no less important, I can now start it first time so consistently that when it doesn't happen, I am surprised.

Also, sadly, the PO passed away a few weeks ago. That's been a lot to process. Not sure what else to say about that.

Thanks again for all the assistance. It has been invaluable.

 

[GrandPaulZ]

...I can now start it first time so consistently that when it doesn't happen, I am surprised.

Also, sadly, the PO passed away a few weeks ago...

Glad to hear the bike is running right.

Sad to hear of the previous owner's passing. Did he get to see it running? (I hope so) Maybe get in a little ride?

 

[dhowlan]

He did get to hear it and see it running. It was still not licensed, so I was riding it in circles in my backyard and he came over. At the time, he kept saying, "It's just so beautiful." I always felt he was far more enamored with it as art than as a vehicle. It was awesome to get it done so he could see it and hear it live again. He loved the sound it makes. I've gotten a bit addicted to that myself.

Unfortunately, riding wasn't something he could do at that point. If that isn't an incentive to ride while you can, nothing is. Strokes are always unexpected and always suck.

Stay well.

 

[dhowlan]

After a bit of back and forth about posting this in a new thread or continuing this one, I've decided this falls under the heading of I'm a newbie and is a continuation of the resurrection.

First, a bit of housekeeping. The handlebars. I realized recently that the end of the bar is not the same as the end of the grip. Due to the positioning of the air "choke" lever, the throttle end is not pushed entirely on the bar. IIRC, it's about an inch out to allow the choke to not rest on the handlebar curve. You'd think it would be obvious that the right hand is farther out than the left while riding, but I didn't notice it until I was adjusting my mirrors one day.

To the far more serious matter at hand. I have an oil leak. After much cleaning and looking, it seems to be mostly the top ring of the exhaust push rod tube. Then it has the wonderfully entertaining property of flowing down to the bottom and all the way round the head to the rear before settling on top of the crankcase. What I'm saying is, it might not only be coming from there, just that it's the start of the flow and the largest leak. This went from not leaking to a teaspoon sitting on the crankcase every ride from one ride to the next. Coincidentally, I recently replaced the oring on the intake rocker/lifter shaft. No idea if that is related or if this was just an inevitability of 50 year old rubber or both, but here we are.

So, clearly the head has to come off and i want to replace the PRT o rings and seals. Also, have to replace head gasket, base gasket, and rocker box gaskets. Anything else? I need to acquire the tappet guide block tool. (on that note, there seems to be black oxide looking versions (CBS and Bonneville parts) and chrome looking versions (lowbrow customs et al). the chrome ones are substantially less $, but I'm not sure it matters. Does it matter?)

I've read several threads on this. TR7RVMan has a few lengthy treatise with pics on the matter. So I feel like i know some things. However, my newfound experience with the Triumph is that each one is unique. I'm really uncomfortable with talk of bending heads with incorrect seal thicknesses and such. I'm sure it will be less of a mystery once I start digging in.

Here's my initial questions. Should I order parts first or take it apart first? Of the parts available, is the top end kit from the likes of the Bonneville shop or CBS adequate? Should I be looking at a specific head gasket? Perhaps most importantly, is there a part of the dismantling that has surprises I should look for? I already know that the cam followers need to be held in place or risk them coming out and losing where they came from. Ideally, I'd like to do this once without messing up a good running engine.

Thanks in advance.

 

[newsh]

I’ve done this job a couple of times on my 650.
The PRT seals can be replaced by removing the rocker boxes, no need to lift the head and barrels.

 

[dhowlan]

As nice as that sounds, and it really does, I'm concerned that the guide block seal will eventually go the same route and I'll end up doing the whole thing anyway. Having said that, thanks for saying so as it has allowed my brain to picture just doing that bit. It feels like that would be a far simpler job with a lot less moving parts. Hmmm.

 

[dhowlan]

Wait, don't I still need to remove the head? How do you do that without removing the head?

 

[StuartMac]

Hi,

I’ve done this job a couple of times on my 650.
The PRT seals can be replaced by removing the rocker boxes, no need to lift the head and barrels.

Errrm ... all unit Triumph twins, the top PRT seals are in the underside of the head ... Only the triples allow PRT seal replacement just by removing the rocker-box.

Hth.

Regards,