Triumph Twin twinshock trials bike.

[Jockser]

Dunno how I missed this the first, and probably the 2nd & 3rd times too ! Gorgeous looking bike Mark
Interesting write-up but, having had a couple of Betas, I think I'd stay away from the Brit iron. It seems a lot of work to keep them going...

 

[earthmover]

My "Bible" for working on the Triumph is in the form of the original instruction manual for the models up to 1963. I have dog eared copies of others for different parts, as by now no engine has the same internals as it started out with. This has caught me out before!



This has a complete "how to" on disassembly, and reassembly which is comforting to have. The underlining is mine:


So with a mallet in hand, we boldly go where I have never been before. Sure enough, the two halves come apart without any drama, and I can see what damage has been done.


Right hand big end. No worries.


Left hand big end, something of a mess. The shells have really had a hammering (photo didn’t come out) which is where the swarf had come from. Sorted out dropping off the offending parts for a re-grind and matching up with oversized shells, and re- bushing the crankcases. We had discussed sleeving the barrel and boring it back to standard at some point, and this seemed like a good point to do that as well.


My new downhill bike?
Mark

 

[dean0n0]

 

[earthmover]

That's a very clean looking build! It is very similar to mine, main performance difference is a Pete Kirkby clutch, and a much better pilot!
Mark

 

[earthmover]

Back to my bike. Now to be fair to Bill, he did say that he was incredibly busy, and might have taken too many jobs on, and the guy who grids the cranks for him had a month off after Christmas, but it was still four months until I saw the parts again. To save repetition, go back to post #111 to see pictures of what had been done, along with grinding the crank, re-shelling and fitting the con-rods, and sleeving and re-boring the barrel to std.
We met at Lymm services, and over a cup of coffee he gave me a list of what and what not to do. (again) He had loosely bolted the crankcase halves together for ease of transport, but I needed to refit the camshafts and then seal the cases. He pointed out that the crank currently had a tight spot when you tried to turn it by hand, but when I put it together, a sharp mallet tap on the ignition end should sort that, and give a little end float. This blew my mind slightly. He also pointed out that he had cleaned out the parts he had, but all the parts that I was putting back on probably had metal filings on them, unless I had cleaned them properly. Three tins of brake cleaner had sorted that. I was still going to reinstate the aftermarket oil filter as well, to hopefully stop any contaminants getting back round the system.
Mark

 

[dean0n0]

That's a very clean looking build! It is very similar to mine, main performance difference is a Pete Kirkby clutch, and a much better pilot!
Mark

He does make it look easy.

 

[earthmover]

So, shall we begin?
After installing the camshafts and loctiting the two halves together, I fitted the bottom end into the frame. This serves the dual purposes of clamping the two halves together, and giving me less weight to try and lift in later!



Then line up the timing gears and fit, using the special tool to draw the shafts into the gears, not knock them on.



Then the oil pump. This has had a thorough inspection as a potential source of the oil starvation that caused the problem, but is working well.
Mark

 

[earthmover]

And now, the fun starts. In my defence, it has been quite a while since I took it apart, and despite taking lots of pictures, some things get forgotten.



Slid the gearbox cluster in, along with the inner cover and gearbox quadrant. Then put the outer cover with the kickstart mechanism, the gear selector, and the worm drive clutch actuator. Both covers sealed with Loctite 510.
Mate rings to see how I'm getting on. Tell him I've just put the gearbox in.
"Did you remember to put the detent spring back in first?'
No, I didn't.
Pulls it all apart again, puts the offending spring back in, sticks it all back together.
Gears click into place nicely, but now the clutch arm won't move. It has a home made extension by a previous owner, to lighten the lever action. If you aren't careful to keep it under tension when you put the outer cover back on, it can fall back and jam. So a little more swearing, and off with the outer cover again. Hold clutch cable tight, re- fasten cover, and breathe.
Mark

 

[earthmover]

With the right hand side of the motor all tightened and cleaned up, let's turn to the other side.

A new drive side seal had gone in before sticking the crankcase halves together. Now for the new drive sprocket.


Then replace the sprocket cover and rebuild the clutch. Have I mentioned getting the clutch basket back while the 20 individual rollers try to escape? One of those jobs that is easier on a bench. Persistence, a pair of tweezers, and an extending magnet.


I had a picture, but it was blurred, so here is the next step. Fitting the duplex timing chain.
And then the ignition rotor.
Mark

 

[earthmover]

Followed by the stator plate, then the clutch plates and actuator rod. There is also a 5mm ball bearing to remember to put in before the pressure plate. Brief wrestle with the clutch springs, and then check the clutch works!
Mark

 

[earthmover]

With the clutch cover bolted up, we can now turn to the top end. To flesh out the story a little, I will explain that when Bill returned all the engine bits to me, they were in one box. Crankcase, barrel, new pistons etc. This will become relevant later.



After having sleeving the barrel and boring it to std, I now have a nasty little lip to contend with. Not to worry, I have two ring compressors and I am a patient and careful worker
(Insert snort of derision here)
First issue I have is that upon opening the box with the two new pistons, is that a gudgeon pin circlip is missing?
Mark

 

[earthmover]

Turned the box inside out looking for the errant circlip, searched the van, to no avail. Decided that it must have got "lost in transit" and checked the four old circlips to pick a likely candidate. Yes, some people are now recoiling in horror. Anyway, with the pistons safely attached, ring compressors in place, and gently ease the barrel down into place.......

There was a barely audible "ping". WTF was that? Lifted the barrel slightly, and this fell out.
Bugger
Mark

 

[dean0n0]

A bit late, but I'd spend some time with a half round file, putting a lead on them liners. Maybe an old Fairy liquid bottle, or the like, to protect the bores.

 

[earthmover]

A couple of days later, and new piston rings arrive. Exceptionally carefully this time, and with the right hand side ring compressor upside down (to fit inside the lip) and we have success!
Re-fit the eight fiddly nuts and washers to their respectve studs, and tighten the barrel down. New seals for the push-rod tubes, then lower the head down into place. Make sure the push-rods are engaged on the cam followers then tighten the four outer cylinder head bolts. Wiggle the rocker covers into position, again making sure the push-rods connect properly with the ends of the rockers themselves. Tighten everything up, apart from the oil line to the rockers, which I leave loose until I can see oil is getting there, and then just carb, exhaust tank and outside to try it out.
A few swings on the kick start with the kill button pressed to make sure there are no funny noises, then a good old welly, and.......
Nothing.
After numerous kicks there is still nothing. Not even a cough. Whip the plugs out, and there is a good spark. Fuel getting through, why no life?
Go back through the mental checklist and remember questioning myself as to which mark on the rotor do I line the stator up with?
Hmm.
Mark

 

[earthmover]

So off with the clutch side cover, its only ten bolts.



The rotor has two threaded holes for a puller, so not a big job. Spin it so the other mark on the rotor lines up with the mark on the stator:



When the pistons are 1.8mm before TDC.
Bolt everything back together, then outside to give her a try.
Sure enough, first kick and she burbles lumpily to life! Sigh of relief, I'm not completely inept.....
I left the engine on tick over until oil appeared at the return, then rattled the unions on the rocker feed to make sure oil was getting to them. Nipped all the unions up, then switched her off to cool down.
An hour or so later I started her up again, and after again checking oil was circulating I increased the revs. Then blipping the throttle from idle to see if there was any hesitation. A little, but best to give her a bit of a run and drop the oil before going any further. So grabbed a helmet and went for a spin round the village. No horrible noises, seems to be pulling well, no smoke, all good! Back into the garage and start emptying the oil via the sump plug, tank drain, and oil filter. Sat on the strainer for the oil pick up in the sump plug, I find this:


FFS.
Mark

 

[earthmover]

The circlip is totally unmarked, so there's no way it has come out of a piston after I had rebuilt it. So it's either the missing one from the box, that has been stuck unnoticed on a crank web all this time, or is it one that has come out of a piston before I put the barrel back on? While I was wrestling with ring compressors?
I sent the photo of the circlip to a select few people who I knew would be sympathetic to my plight. After they had finished laughing, they all agreed the only way I was going to be certain, was to tear it down again.
Mark

 

[earthmover]

The good news is, I can remember how to do it this time.



Off with it's head.
Upon carefully lifting the barrel, I find a full compliment of circlips, snug in their grooves. Part of me is miffed, I stripped it down again for nothing. Part of me is glad, no second guessing any little noises.



Head and rocker boxes back together.



Exhausts, carb, ancillaries all fastened back together.



And then I wonder why my phone is dirty?
Mark

 

[earthmover]

After going through the idle, run, and test ride again, all is good with the world. I tweaked the carb settings a little to get rid of the hesitation off idle, and then checked the sump strainer again, just to be sure.
With the sump guard bolted back on, it was off to an uncharacteristically sunny North Yorkshire for a trial.





Obviously not a picture of me, that's my mate Mark on his Bantam. The Triumph performed perfectly, the rider less so!
Roll on the next.
Mark

 

[Big Geordi]

Crackin pics and write up only just found this grand job!!