Triumph Twin twinshock trials bike.

Well the trial wasn't the most sucessful as far as riding goes. I dropped the Tiger Cub in a stream in the second section and drowned it. (and me!) Thankfully ten minutes of kicking with the plug out cleared it and I was able to finish.
As far as the Twin goes though, I came away with plenty to work with. First off a couple of ideas to try, and second an order for some bigger jets from Amal.
Before I got chance to look at this, my rear axle arrived, so first job was to put its own wheel in instead of the Whitehawk's. A rummage through my spares boxes turned up a handfull of spacers to fix the wheel in a roughly central position, to be finalised when we see how the chain runs.

DSC_10083-L.jpg


An old torque arm off a TY was shortened and pressed into service, and a cable adjuster bodged to hold the cable on the rear brake arm.
The second hand Tiger Cub wheel came with a nearly new 48 tooth sprocket, so this was my starting point for gearing. I have various old runs of chain which were good enough to experiment with, so cut one to the right length and fastened everything together.

DSC_10086-L.jpg


With an idle five minutes I fastened the mudguards on. The alloy ones look fantastic, but don't crash as well as plastic, so a pair of white Universal were bolted in position. These may get swapped for better looking ones in the future, depending on my mood.

DSC_10087-L.jpg


DSC_10091-L.jpg


I will get the front brake cable sorted, honest!

DSC_10092-L.jpg


The new jets had arrived, so I put the next size up, a 160, in and wheeled it outside to try. This was much better, but still hesitant just off tickover. I put the 170 in and with a bit of tweaking on the air screw got it to nigh on perfect.
A quick celebratory blast up the farm track and it sounds glorious, with an evil cackle on the over run. Very un-trials bike like!
Unfortunately the gearing is too high, so next on the shopping list is a 54 tooth sprocket!
Mark
 
I'm liking the look of that Mark and a tad envious i might say; I bet your made up with it :thumb2

That engine was fitted from new, as you probably know, with the Amal Monobloc carbs which, tbh i prefer;
I never did seem to get on with the MK1 concentric carbs.
 
That engine was fitted from new, as you probably know, with the Amal Monobloc carbs which, tbh i prefer;
I never did seem to get on with the MK1 concentric carbs.


That's interesting, when I raced grass track bikes (in younger days!!) all bikes would have concentric carbs if they'd originally had monoblocs :beerjug:
 
That's interesting, when I raced grass track bikes (in younger days!!) all bikes would have concentric carbs if they'd originally had monoblocs :beerjug:

I didn't mean they were no good just that I didn't have much luck getting them right which is probably more a reflection on my skills than the carbs :D
 
I didn't mean they were no good just that I didn't have much luck getting them right which is probably more a reflection on my skills than the carbs :D

Yes, they're a bit crude to say the least although I had one on my last Triumph twin I'm sure a Mikuni would have been much better.

Anyway Mark, watch you don't dent that tank :eek::eek::D
 
There's a guy on Facebook makes custom front number boards for trials bikes.

DSC_10094-L.jpg


This is the view I should see most of, although as Tim will no doubt suggest, I do see far more of my bikes from a distance..:D

DSC_10090-XL.jpg


Mark
 
This is the view I should see most of, although as Tim will no doubt suggest, I do see far more of my bikes from a distance..:D

So harsh, although I am looking forward to seeing the underside on the steep sections :D

You've done a great job Mark, best looking Triumph I've seen in a long time :clap
 
Nice! Love it. I've always had a thing for Trumpet Twin Trials.
 
Every "little" job I start turns into a big one. Nothing fits exactly as you'd expect it to, but I suppose this is the fun of such a build.
One such job was to connect the rocker oil feed pipe to the spur off the oil tank. A short length of hose had been on as a bodge, but immediately above the exhaust didn't bode well for longevity. The two pipe o/d's were slightly out, 5mm to 4.5mm, or the imperial equivalent. A 5mm compression fitting took up the slack and stopped me worrying.

DSC_10095-L.jpg


The new 54 tooth sprocket arrived from Talon. This is the biggest "off the shelf" sprocket they do for the Tiger Cub hub, but they will make anything you want. I hope I don't need anything bigger, this is huge! I cut another old length of chain to the right size and threaded it on. Seemed a bit stiff, just put it down to the newness (ahem) of the chain in question. It was only when I tried to put the split link on that I realised that it was an o-ring chain, and it was too wide to go through the gap between gearbox sprocket and the back of the clutch housing! And now it was in there, it was a b*st*rd to get out! :blast
Happily, I knew where there was another length, but it took nearly an hour to get.
With this duly wrapped round the sprockets, a quick trip round the garden confirmed that the gearing is lower. Is it low enough? Ask me after the first trial!
Next job, fit a chain guide. I bought a universal one from Sammy Miller, and using the old maxim of measure twice, cut once, made it fit.

DSC_0099-L.jpg


Next little job was to sort out an inner mudguard to fit below the main one to stop too much crud getting at the back of the engine. Part of ann old front MX guard did the job admirably. (the other part of the guard is the hugger on my GS)

DSC_0101-L.jpg


Another bodge fixed. The connector for the brake arm was turned down for me from an old clevis pin.

DSC_0102-L.jpg


And here's the set up with the chain guide, inner mudguard trimmed to fit, and a new chain!

DSC_0103-L.jpg


Getting closer. Just a few little jobs before it's maiden outing, our club trial on 11th June. Made a rash promise to have it ready for then!
Mark
 
Would have gone along to witness the first outing Mark but i'm off down country.
It does look the part, hope it does the job for you.
 
So, the little jobs. The chain tensioner still wasn't in the right place. A few washers spaced it out better. The front brake cable outer was shortened so that the piece of meccano could be jettisoned. The seals on the forks were leaking, so I stripped them down, emptied the sludge out of them, and refilled them with fresh oil. One leg has a slight bend to it, but as long as it is positioned correctly it doesn't cause too much of a problem. The awful carbon look stickers were binned, as were the concertina type fork boots. Some clubs insist on them if you enter the Pre 65 class, but I really don't like them. A pair of caps from a set of Montesa forks look so much better.
Whilst fitting the front mudguard to the fork brace I realised that the bolts had distorted its curvature, so I undid it and rebolted it with a piece of hose underneath to give it shape. The last thing was to put the tank badges on. I wanted green ones, but now that I've done it, I think the red ones look just fine. On Saturday, after finishing some odd jobs for my Father, I threw the bike in the trailer and went to the yard to try it out.

DSC_10112-XL.jpg


DSC_10113-XL.jpg


DSC_10114-XL.jpg


DSC_10116-L.jpg



Unfortunately, the lowered gearing isn't low enough, and the carb jetting isn't rich enough, as the bike is too quick and too responsive. I could probably ride around one of the two, but not both. :( It would make a pretty good motocrosser as it stand at the moment!
I took it to today's trial, but took the Cub to compete on. Parking it near the butty van drew a stream of compliments, and some ideas as to what could be done to calm it down a little. After the competition was done, I had a play around on it, and invited some of the more knowledgeable members of the club to try it and offer their opinions. The consensus appears to be that a smaller carb would help, as every other Twin is on a 622, whereas mine is a 626. Otherwise it was very well received, one of the experts blasting it through a section with ease, and proving that I may need to work rather more on my technique! :D
A couple of people have offered to dig out a carb for me to try, so that will be the next little job.
 
Well Mark was good enough to let me have a little spin on his beautiful Triumph at the weekend and have to say that unlike an online date, this bike is even better in the flesh!

All pre 65 bikes only work because of the attention to detail and even though Mark was born after British bikes were the norm he's done a sterling job, I really can't wait to see him in action on it :clap

Since seeing it on Saturday I've been wracked with guilt about neglecting mine after my last dismal trial when my own bike was handling so badly I didn't finish.

Started at 7am this morning and got stuck in with a full fork rebuild and much tweaking here and there, plus a good clean to finish off.

Feels much better now, so thanks for the inspiration to sort mine :beerjug:

DSCF4151-XL.jpg
 


This was the result of a call to Surrey Cycles, who supplied an Amal Premier 622, jetted to suit my intended riding. The bike is now a lot calmer, and throttle control is far smoother.
Might just be able to compete on it now.....:D
Mark
 
As he mentioned, Tim came over to see the bike in the flesh. As I hadn't seen his 950 either we spent a long time talking and pointing. :D

 
A nice one from my local thumper trial

I saw that one, or one very similar, on eBay a couple of years ago. That could have been the start of this odyssey!

After the session at the stables with Tim, I washed the bike off and parked it up, as I was off to the Alps for a little over a week (more on that later).
Another practice session on Saturday, with Denise's daughter Hannah, currently mad keen on trials, and I started to test the bike some more. Whether it was because I was getting more used to the handling, or getting less scared of it, I don't know, but I started to catch the odd splutter when I asked for the throttle. This wasn't ideal, as its debut was the next day!
The first section was nerve wracking, as most of the riders were watching, but thankfully cleaned it! I had dropped down a class in honour of the new bike, so that was a nice confidence inspiring start. Kev Ellis stopped me on the way out of the section and tweaked the carb settings slightly, which helped. Mark Newman, another of the regulars, said he had a box of jets in his van, and we would have a play after the trial. Managed to stay clean until section 6, which had a tight uphill turn across a stream. I drifted a little too wide and ended up with a three. My fault entirely. Section 7 had a tricky turn along the edge of a gully, which played upon your nerve. I chose discretion, and another three. Cleaning the last 3 sections and my first lap on the Twin had only lost 6 marks. I was very pleased, but a bit disconcerted to note oil leaking from the bottom of one of the fork legs. Being used in anger certainly shows up any weaknesses! The rest of the trial was very enjoyable, the score went south with two 5's, one for stalling, and one for missing my footrest, but I did manage to clean the two sections I had earlier had 3's on.
After the trial, good to his word, Mark Newman dug out his Amal box, and we had a fiddle. The setting I thought was already quite rich with a 120 main jet, he ended up increasing to a 150. This cured the hesitation just off idle, and in so doing smoothed out the jerky response. Looking forward to the next trial now, which is one of the Northern Brit Bike Championship rounds.
Mark
 
Update.
The Northern British Bike Championship is a seven round series of road trials, always well supported and with some fantastic riding. I had missed the first two, the 3rd I had ridden the Cub, the 4th was to be on the Twin. The West Riding Trial last year had ended in a deluge, but this year we had glorious conditions. I started badly, losing 9 marks over the first 4 sections, but then settled down and began to really enjoy myself. The front end was giving me cause for concern though, a common Pre 65 problem. Modern bikes have very stiff yokes and forks, giving excellent steering control. The forks I had on were wayward to say the least!

IMG_0228.jpg


My riding companion at that trial was Mark Newman, he who had helped with the jetting earlier. It was also he that had let me ride his Pre Unit Twin that I had been disappointed with a couple of years ago. He was very taken by the Drayton frame, and had been making some enquiries about getting one himself. The Maroon coloured bike from the show was for sale as a rolling chassis, the engine having let go in a big way. Mark did the deal and told me he was going to take his time and build it up with an engine he had found, probably as a project over the summer. Which is why he appeared on it not two weeks later!

DSC_0317-L.jpg


DSC_0308-L.jpg


DSC_0307-L.jpg


Mark
 
We swapped bikes a few times, trying to pin down the differences between the two. They were only slight, but mine had a smoother power delivery, whereas Mark's had much better forks.
We were fairly well matched in the trial itself, until the start of the fourth lap. I had cleaned the section 3 times previously, but on this attempt my front wheel had clipped a rock and twisted sideways, pitching me over the bars. As the bike crashed down on its side behind me, there was a slight tinkling sound, which I found was the alloy shock collar off the left side rolling away down the section. I had snapped the end off the shock.

DSC_0319-L.jpg


Trial over I pushed it back to the trailer. There is a class for Air Cooled Monoshock trials bikes, but I didn't think it prudent to try and ride anymore that day.
Slight panic though, as the next round of the NBBC was only a week away, with the Llangollen club round. Rockshocks are fully rebuildable though, and a couple of days later I had the repaired item back and ready to go on. The fall, or rather cause of the fall, had made my mind up though. I needed some new forks.
JB had mentioned REH forks earlier, and a lot of other people besides. One of the experts at the Aqueduct club had gone to great lengths to explain the differences between the current new Pre 65 eligible forks on the market, and after trying the front end of his bike I was convinced. I ordered a set, to be collected at the Llangollen trial. I did ponder trying to fit them beforehand, but dismissed it as too much of a rush.
Mark
 


Back
Top Bottom