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Discussion Starter #1
Hi
I have had a leak from the left fork on my ‘76 T140V. The oil seems to be dribbling down the gaiter so I’m thinking it’s from the fork top rather than the fork seals. However I’m confused by the collection of washers at the caps and the instruments brackets. The parts manual shows one washer. I have two per side. One that fits around the fork cap ( but seems only to be held in place when the instrument bracket is fastened in place over it). The manual doesn’t mention the level the fork should sit in the triple clamp. Should the cap sit above the clamp? And how much, as this would seem to dictate the relevance of that washer?
And then the brackets have washers - but one side has a washer that seems to relate to the diameter of the Top Cap Nut - to protect the chromed bracket? The other side seems to have a repeat of the first two washers.
The manuals seem to show only one washer. If that’s so, then which is it, and where does it fit?
Thanks
Simon
Ps. The manual does say there should be a thread sealer used with the fork cap, which I’m supposing is the source of my leak?
 

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What does the parts book say? The fact that your bike has an oddity suggests that someone's fiddled. So maybe they didn't seal the threads? 40 years is a long time and stuff happens
 

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Discussion Starter #3
Parts book shows this
715203

But mine looks like this
715204

With this washer that fits around it, rather than under it
715205

and the top cap washer looks like this (on one fork, the othe has what looks like a repeat of the larger washers that are around the fork caps)
715206
 

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Hi Simon,

The manuals seem to show only one washer. If that’s so, then which is it, and where does it fit?
Lower image in your last post shows part 37 (97-4166 "Washer") correctly fitted on part 36 (97-4395 "Cap screw").

Otoh, middle image in your last post, showing a washer around part 40 (97-4387 "Top nut"), this washer has been added by a PO.

manual doesn’t mention the level the fork should sit in the triple clamp. Should the cap sit above the clamp? And how much,
It would help others' understanding if you use the same terminology as the parts book; nevertheless, by "cap", an educated guess says you mean part 40 97-4387 "Top nut".

Essentially, it's up to you to set "the level the fork should sit in the triple clamp". Ideally, a speedo. or tacho. bracket is trapped tightly between part 36 and 37 on top and part 40 underneath. The brackets have a turned-over edge on their underside for strength; the friction between a bracket and parts 36, 37 and 40 is greatest if they're all tight before the bracket edge touches the top surface of the yoke and the yoke paint isn't damaged if a bracket doesn't touch it at all. So use your judgement?

the brackets have washers - but one side has a washer that seems to relate to the diameter of the Top Cap Nut - to protect the chromed bracket? The other side seems to have a repeat of the first two washers.
Having identified the Triumph Washer(s) and the one(s) added by a PO, note the Triumph Washer is also a similar ID and OD to the top edge of part 40 97-4387 "Top nut". So a second washer at the top of each fork leg would be most useful between the Top nut and the underside of the bracket, to reduce the scratching of the bracket chrome by the top surface of the Top nut.

manual does say there should be a thread sealer used with the fork cap, which I’m supposing is the source of my leak?
Depends on the source of the leak? Ime, regrettably top edges of stanchions are easily-damaged by DPO pounding on them either to release them from yokes or fit them in. :rolleyes:

If you find a thread sealer is required, bear in mind the stanchion thread is fine so very difficult to degrease without dribbling degreaser down the stanchion into the fork oil. :(

Hth.

Regards,
 

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I use Swak on this part, its a Teflon based sealer that seems to work well for sealing your fork tubes.
Sounds like a good excuse to pull the forks out and give them another life [ie rebuild/reseal new oil etc].
 

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Discussion Starter #7
So an update: I drained the oil and found the the left fork (which was the leaking one) contained 240cc of oil! The right had 235cc. So I replaced 190cc into both and took it for an hour or so up the road. So far no leaks.
 

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Hi Simon,

drained the oi
left fork ... contained 240cc of oil! The right had 235cc. So I replaced 190cc into both
So far no leaks.
Excellent. (y)

Just as a matter of interest, can you remember if the springs looked standard - coils same spacing apart throughout their length - or they're progressive springs - coils closer together at one end, further apart at the other?

Regards,
 

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Discussion Starter #9
I didn’t pull the springs this time and my memory of what they were when I did is a bit hazy. I want to say that they were not progressive 🤔
 

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Hi Simon,

I didn’t pull the springs this time and my memory of what they were when I did is a bit hazy.
No worries. :) I've been replacing with Progressive springs for years and their instructions advise oil quantity by height inside the leg (modern way of doing it apparently) and I've taken to doing all Triumph forks that way, although Triumph wasn't super-accurate about the depth inside sliders ... :rolleyes:

Regards,
 

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Discussion Starter #13
Hmm 🤔. Interesting. What springs have you fitted? Not sure if I’ll change them, but then again....
 

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Hi Simon,

What springs have you fitted?
Progressive Suspension T140/TR7RV springs.

Not the whole story though. I also replace:-

. Standard damper head O-rings (97-4003) (a known source of stiction) with https://www.triumph-spares.co.uk/damper-valve-seal-conversion-1971-on-pair-97-4003p.

. 'Recommended' ATF with Bel-Ray fork oil.

. Standard dampers with one of the after-market replacements - unfortunately, these are all spendy, they make a noticeable difference but ime the cheaper bits above will too. :)

I also prefer '78-on Super Seals (97-7010) to the pre-'78 97-4001 and I fit gaiters - specifically those made by Andover Norton as they don't convert themselves into a stack of large O-rings.

Hth.

Regards,
 

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Discussion Starter #15
Thanks for that advice Stuart. Going forward I’ll certainly consider doing as you’ve recommended.
This was my uncles bike originally-bought new by him in ‘76. I took it over some years back but after partly dismantling it for a paint freshen up I moved house and in the intervening time lost track of what I had done. So to cut a long story short I had a local mechanic I knew reassemble it for me with a few small styling mods too. This was a little over 2 years ago. A few little teething issues caused me to not ride it much and as I have another bike it wasn’t a priority.
But now I’m eager to use it more and after looking into a few of the issues found that the reassembly had been a little ‘off’. Things not quite as they should be. So I’m intending to work on it myself from now on wherever possible.
Probably the next issue to address will be its unwillingness to idle when hot. It’s running a electric ignition (Boyer) now (which I have no idea about working on - so hopefully it’s trouble free) but I am suspecting a fuel restriction on the right side. The carb tickler takes much longer on that side to dribble fuel and often requires tickling to start the bike even after a short period of not running. Ie 10 mins. Maybe the filter in the tank? Or the carb fuel bowl needs a clean out? (It has sat quite a bit in the last year since recommission). Or is it just a feature of the right carb leaning to the left when on a side stand?
Either way, I can report that I really enjoy riding it even compared with my Bmw R9T.
 

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The fuel supply issue could be down to the type of tap you have. Some taps have a neoprene insert that swells with fuel over time and slowly covers the hole in the tap. The fix is to remove the tank and twirl a drill bit in your fingers with the tap open. The aim is to cut away the swollen rubber and open the hole again.
 

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Hi, Slow tickle can be lack of fuel or low float level. Clean the pilot jet passages. Those are important to idle & good starting. You should be about 1.5 turns on mixture screws if all is well.

Stay up floats & viton tip alloy needles are a must for old carbs, but don't throw money at worn out carb.

In hot weather the bike will do better if idle is set higher. 1050-1100 or so. Readjust mixture screw as needed until you find best happy medium. Worn slides will cause unsure idle also. Sometimes ok, others not. I found that on my '73 Tiger. One clue of excessive slide/carb wear is with motor fully heat soaked, ever so slowly open throttle when bike is at idle. If it stumbles bad or wants to die or often actually will die, that can be caused by wear. Often while riding at lower speeds you back off throttle to zero, then slowly add throttle & you feel a flat spot or motor may even die for a split second, again sign of wear. Play around with this & see if you can see if this is happening.

We ride in 110f all the time. Doesn't make bike leak or anything. Our fuel boils in carb when parking bike. Most often to restart we need to do full tickle, hold full throttle & a hard kick starts right up. Will go to 6k instantly so be ready to back off throttle. Will not idle until carb cools so keep blipping throttle so it doesn't die. About 2-3 min to cool carb. No type of heat insulator for carb helps. Air gap or thick insulator block does the same.

I have found extended riding at 60-65 mph at 110f tends to slightly increase oil consumption. From none in cool weather to 1/4-1/2 cup in very hot weather every 400 miles on my bike.

Boyer timing is easy. If timing light uses external battery, hook light to BMW's battery, not Triumphs. Set timing like it shows for points in shop manual. Refer to Boyer website for you type Boyer, but many are set at 4000. Place center stand on padded surface like an old mud flap or carpet so bike won't walk. Hook up timing light & rev. In needed remove points cover. Slacken pillar bolts slightly rotate the Boyer plate on it's slots until timing mark lines up. Trial & error will teach you how much to move it. If you run out of slot you need to slip the rotor on it's taper. It's not keyed like the factory AAU is. We'll get into that if needed later.

Check your valve adjustment if haven't already done so.

Always use highest octane fuel available. Hot weather wants higher octane.
Don
 
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