Triumph Twin twinshock trials bike.

A couple of photos pinched off facebook, from the first trial of 2019.

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Hecklers from the side of the section making me laugh.
Mark
 
Still carburating well? I was wondering what effect a smaller carb would have.
 
Still carburating well? I was wondering what effect a smaller carb would have.

Perfect thanks. Took quite a bit of "experimentation" but got there in the end. One of the other Twin riders was asking on Sunday, as his coughs and spits a lot.
Mark
 
It would appear that I have unwittingly deleted the wrong photo from my Smugmug account, so the post 119 is missing something:
I had two jobs to do on Saturday, one was sort the jetting on the Triumph, the other was to try to talk some sense into a teenager. Hmm. :augie
Beauty and The Beast.

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Which one is which depends on the day. :green gri
Mark
 
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Trial last Sunday, just off the A5 near Corwen. Road racer Paul Owen in the middle on his Bantam, Myself on one of the 5 twins there that day (common as muck now), and Mark Newman on his 320 Norton.
Mark
 
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After my disappointing end to the 2018 Manx Classic Two Day Trial, I was pleased to get an entry to this years event, with the hope of sorting some unfinished business!

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At 9.00 on the Friday morning I rolled up at Mark Newman's house to load the Twin into his van, along with Niel Walker's James. We were booked on the 2.00 pm ferry from Heysham for what promised to be a rough crossing. Once safely aboard the navigation officer came over the tannoy to warn of force 6 to 7, occasionally 8, and a bumpy ride as we neared the Isle of Man. Mark has had seasickness before, and was understandably concerned. I have never suffered from it, so was less so. As it was, despite the horizon moving up and down quite significantly, the biggest problem was getting back to your seat with a still full glass! There were some people on board who had an unpleasant few hours but thankfully none of our lot.

Next day and the start of day one.

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From left: Russ Jones, myself, Paul "Moz" Owen and Mark Newman.

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The sun was out for most of the day, but showers meant the waterproof jacket was never far away.
I was looking forward to the continuation of a run of good form, but that went South from the second section as I made some easy stuff look difficult. It took a few sections for me to settle down and get into a groove. Riding with Mark Newman we were on similar scores by the end of the day, he a few marks lower. We then found out that we had both incurred time penalties, which was very annoying. Those who know my riding will understand how much that hurt!

Day two saw pointy elbows out, and no more Mr Nice guy. (queue for a song?) Mark and I developed a system that minimised our time in the line up for each section and soon had us away from the madding crowd.

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Concentrating hard.

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Mark finds the stutter on his Norton, a fouled plug.

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Quick selfie before setting off to the next group of sections.

Needless to say we didn't get any time penalties on day two. I had slightly less marks than Mark, having had a really good ride. Finishing midway through the field, my result could certainly have been better. Lets hope I get an entry for next year and a chance to improve.

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A flat calm return crossing gave chance to ponder on what could have been, and to plan some improvements gleaned from other bikes at the event.
Spanners out again......
Mark
 
Great update Mark and I have to say (although it grieves me :D ) you're riding it very well :)
 
Thanks Tim.:D

Paul, there are two Classic trial clubs nearby who run local trials every month. There are no more "big" trials for me this year, but I hope to do more next year.

Mark
 
If you go back to post #120, you will understand why I have a “saved search” on ebay for a wide ratio gearbox cluster. Since then I have acquired a couple of parts books for the Triumph Twins, one from 1959 and one from 1964, to help try to understand the various little quirks that these engines have. I now know that the gearbox cluster in my engine, and the one referred to in post #120, are the standard ratio from the earlier models.
Just before the Manx the saved search came up trumps, a set of wide ratio gears that actually matched the number of teeth in the parts book.
I put in a bid of what I thought they were worth and crossed my fingers, as the auction ended whilst I was on the ferry to the Isle of man. Happily, I won, and at a fair price.

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Whilst competing in the Manx, I spotted that one of the other Twins there had the spark plugs in a different location. This attracted my attention, as I keep catching the left hand plug cap with my knee and knocking it loose. Not enough to stop the engine, and I can quickly push it back on, but one wet day this is likely to hurt! I asked further about this modification and it turns out the owner had had a fall where the sparkplug had snapped and stuck into the side of his knee. Hmm. :eek:
Once back home I contacted Bill who had rebuilt the engine last year, to see if a) he had heard of this mod, and b) if he could do it? He had heard of it, and knew what it entailed, so we arranged for him to collect the head from me a week later. In the meantime, mindful of problems other people have had with different gears I set about measuring shafts and clearances on the gear clusters. All seemed ok, except the layshaft had a smaller end diameter than mine. I rang Bill to ask about sleeving this to fit while he was doing the head. He explained to me that the later models had a needle roller bearing where mine has a bush, but why didn’t I just swap the “fixed” gears off the new layshaft onto mine? Because I didn’t know you could do that. But I do now. :D

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Spot the difference. Not the clearest of pictures I know.
Pulling the gearbox apart is becoming very easy now. Before I started though, I made a chart of how many crank revolutions were needed to turn the rear wheel once in each gear, with the set up I have been using for the last couple of years.

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With the gear selector side all bolted up, we can turn our attention to the clutch side.

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New seal should keep the gearbox oil in.

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New 14 tooth gearbox sprocket.

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New seal in the sprocket cover should keep the engine oil in.

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The clutch hub is keyed onto the shaft, then you have to painstakingly refit all 20 rollers for the clutch basket to spin on.

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Then the clutch centre and torque up the nut and lock tab it on.

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Top tip for refitting duplex chains with a split link. Pull the ends together first with a cable tie.
When I came to fit the clutch plates, and then the pushrod, there was a head scratching moment. The clutch wouldn’t disengage. It was almost as though the pushrod was too short?
For the moment I ignored this problem and set to counting crank revolutions with the new ratios.
As I had been led to believe, 4th gear was almost identical, but the spread of gears was much wider, leading to an exceptionally low 1st gear. This meant I could change to a smaller rear wheel sprocket to get back to the 1st gear I was used to, but now with a higher 4th gear and the subsequent rise in road speed.

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New sprocket is 44t, old is 54t. Something of a difference!
Now to look at that clutch problem before refitting the head.
Mark
 
So, back to the clutch problem. I had backed off all the adjusters as usual, but no matter what I did, I couldn’t get more than a fraction of movement at the clutch backing plate. I haven’t missed anything out, and I haven’t changed the position of the clutch actuator. It’s as though the pushrod has shrunk, or maybe the mainshaft is longer……….
That was perhaps the only measurement I didn’t check, concentrating on the internal sizes for the gearbox, not where it exits for the clutch.
An easy fix is to drop a 5mm ball bearing into the hole in the mainshaft, between the pushrod and the stub for the backing plate. Voila! I now have full lever movement and the backing plate releases.
Except, the backing plate now doesn’t connect fully with the plates, only 1mm out, but obviously that isn’t going to work.
Out with the parts books. If you cast your mind back to post #6, I was surprised to find an odd number of clutch plates, 4 friction to 5 steel. I was told that was correct, and now the 1959 parts book confirms this. In the 1964 parts book however, it now has 5 friction and 5 steel. The clutch basket part numbers are the same, but the shafts are not. This isn’t really conclusive, as the gear teeth numbers have also changed on the standard gear cluster. I had ordered new clutch plates though, as I had started getting some slippage last time out. It had been pointed out to me that I may have had my moneys worth out of what were the original (from when I bought it) plates.
With ten plates fitted the clutch works perfectly. My conclusion from this is that the mainshaft must be slightly longer, the only way I can confirm or deny this is to strip it down again though, so sod it until next time! Sorry there are no pictures, but I had other things on my mind.

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The cylinder head after Bill had drilled two more plug holes for me. You can see the originals top and bottom, with the new ones in the centre. It now needs 12mm short reach plugs, so I contacted one of the riders I know who used to be a rep for Champion. He has comparison charts for various manufacturers, and gave me three equivalent options to the plugs I had been running, and where to get them from. Cheers Ian!

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With the head bolted on and the original spark plug holes plugged.
The now usual fight to get the valve clearances right. The left hand inlet valve was far too tight last time I had the head off, and it is again. Still scratching my head on that one.
With everything back together it’s outside for a test. It never ceases to amaze me that she fires up first kick whenever I have had the motor apart! The usual checks to ensure oil is getting to where it should before giving it any revs, but then a tappety type rattle starts. Whip the covers off and lo and behold, left inlet clearance is loose now. Adjust it back up and run again to be sure.

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Then for the moment of truth, helmet on and off up the road. By my calculations, I should now have the same 1st gear, but a 20-25% increase in road speed in 4th. With no speedo to confirm this, I can however tell the difference straight away. Riding at what I would consider to be trials road speed, the engine is at much lower revs. Obviously a 20-25% increase on 25 mph only takes me to around 30 mph, but this is what I hoped to achieve. Roll on the next road trial!
Mark
 
Fantastic job Mark, thus has to be the best of all Triumph twin trials bikes out there now.....gis a go Mister :)
 
If I'd known you were at the Manx, I'd have shouted TOSSER at you. The Manx Classic is my favourite part of the 'Festival of Motorcycling' :thumb
 
Brill!
Great following you in this thread 👍
 
Great read really enjoying your journey :thumb2 Whilst I have been to many Classic Scrambles and ridden in a few I have never been to a Classic Trial I will have to put it on my bucket list :thumb
 


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