Triumph T150 1000cc Special

The Build

February 2022 Update

The frame is now back from Performance Powder Coatings near Canterbury. It looks superb!

I can now start the build! First thing is to bolt the frame halves together. Attach the centre stand followed by the swing arm and shocks, battery holder, oil tank, front fuel tank mount, oil cooler, fork yokes, grab rail and various other small items including sorting out the custom electrical tray which will take the coils, relays and rectifier.

Then up to a rolling chassis with forks and front & rear wheel.

The 'bike' will then go off to have the engine built into it. Apparently it's a lot easier due to the shear weight of the engine. Ordinarily I'd do it myself. However, I have built twins before, but never a triple, and I know they are complex and need very careful assembly, so I'm not going to attempt it this time.

So there'll be a small gap between the updates as I will also have to get the bike off for the custom exhaust to be made.

Generally though, things should now continue at pace!

rear plates.jpg

Plywood template for rear passenger foot peg and silencer mounting. Not quite right as new rider foot peg position means passenger feet will be too close. Back to the drawing board for some tweaks. 


At last a basic rolling chassis.

A problem has arisen. What I thought would be a straight swap of T160 rear end into the T150 seems to have gone a bit pear shaped. I don't know how or why but Central Wheel have done the rear wheel offset and it's way too far to the right. I make up special aluminium guides and, in conjunction with a plumb bob, determine the exact centre of the frame and how much the wheel needs to be moved back to the left. It's about 8mm. Central Wheel will do it for free, but I have to pay for postage both ways and an extra £40 for them to remove and refit the rear tyre!

Luckily, I find a local company (VIZMOTO) in Lydd, on Romney Marsh who can do it. It's a set back and extra cost, but I need to get a rolling chassis built to give me the motivation to carry on.


In the meantime I get cracking further on what seems to be a very complicated wiring harness. There's 3 parts: accessories like lights, indicators, horn, instruments etc, charging and electric start. I hope I'm doing it right!

The rear wheel is altered and back. I have all the brakes hoses, so on go the wheels, hoses, yokes, handlebars etc.

It's taking shape, but once again I've come to a standstill as I need things like the mudguards back from the paint shop so I can sort out final brake hose routes, fit rear indicators etc. I'm getting nervous about finding an engine builder as everyone seems so busy, and I'd like to get it done as locally as possible.

While I'm waiting I send off the seat for re-profiling and I buy a standard exhaust. I hate the looks of factory exhaust, but I will need to get an MOT eventually so that I can ride the bike to someone who can make a bespoke system for me.

May 2022

I have the painted parts back! They look great, and I'm pleased with my colour choice. Thank you to Paul's Paint Shop in Rye, East Sussex. I can now fit a few more parts, connect and bleed the brakes and connect a few more wires.

On the engine front progress is slow. In fact, that's nearly all that's holding me up now from finishing the build. It seems everyone is just too busy, certainly those who are in easy reach of where I live.

To that end I have decided to start on the engine build myself. I'm pretty confident with most of it. I'll at the very least do the bottom end and see where I go from there. The stuff I'm not so sure on are things like pushrod seal crush and I know that the clutch needs to be carefully assembled and set up. With regards to the former, I'm investigating adjustable pushrod tubes which should make life easier. I'm hoping the engine build won't be full of horrible surprises, especially since nearly every component is new. So I'm swatting up and watching YouTube videos whenever I get the chance. One thing I will need is a reverse gearbox camplate from Dave Madigan. He's yet to send them for heat treating. I'm reversing the gear change lever to suit the moved back foot pegs, but I'd like to keep the one down four up gear select if I can.

front wheel.jpg

Billet 82mm standard weight crankshaft with steel conrods

stage 1.jpg

First stage of the engine build. Note heatshrink to protect conrods. Crankshaft pinion is way too tight a fit

June 2022

The first attempt at building the bottom end turned out to be a (needless) disaster. I did a dry build, but only lightly tightened the crankcase bolts. Everything span freely and I was excited to crack on. I used the excellent and very sticky Wellseal on the joint faces. Unfortunately, the moment I torqued up the drive side the crank became so stiff to turn I had to use a socket to rotate it. This was not good. When I just loosened the bolts the crank rotated freely again.

Rather than thinking it through, and going by my past experience of building twins, instead I went into instant panic mode!

I tried to get the drive side crankcase off before the Wellseal made life difficult. It took me hours of tapping, heating and general cajoling to get the damn thing off. Stupidly, and unnecessarily, I'd used bearing fit on the crank end which made it so difficult and stressful I though I might have a breakdown.

When I finally got everything apart I had the onerous task of cleaning off all the Wellseal , plus cleaning the crank and internals of the cases. I logged on to to try and get an answer and also spoke to Chris Rooke who is something of an expert on building triples. Chris suggested trying again, but fitting the drive side first. Meanwhile the Triumphrat forum had come back suggesting I tap the end of the crankshaft to get it to free up. I suddenly realised that I have had to do this on past builds. Consequently I also realised that I had spent hours trying to get the cases back together when I needn't have.

Anyway, I guessed the 'problem' was due to the billet crank being machined to such close tolerances. This meant the drive side bearing was a pretty tight fit on the crank. So when the drive side casing was fitted it was pushing the crank right over to the timing side and I can only think the flywheels were binding slightly on the centre bearing mountings. Giving the crank a couple of hefty taps on the timing side end with a large rubber mallet slightly re-centred it and 'hey presto', it rotated freely again. Phew! I only hope I haven't  done any damage to the cases when I had to take it all apart. But, I think I'm OK. However, another consequence of the close tolerances of the crank is I'm now finding it extremely difficult fitting the crankshaft drive pinion. It's just too tight, despite heating up the pinion. I have decided to order a can of freezing spray to apply to the end of the crank to see if that helps. So for the time being I've come to a standstill...

July 2022

The problems are resolved and I can finally fit the pistons, barrels, head, Dave Madigan adjustable pushrod tubes and rocker boxes. Even this wasn't straightforward as I found out too late that the tappet adjusters I'd been supplied with were too short, so I couldn't fit any lock nuts. I discovered that there was a longer set available. Being mushroom head I couldn't just unscrew and replace them so I had to remove the rocker boxes. I then found out that the crankshaft pinion nut wouldn't do up all the way because it was too long! There is a shorter version available! Is someone trying to tell me something?

Anyway, I finally reach that milestone when the engine (albeit part-built) can go into the frame. I can now proceed to fit the oil lines and thermostat and fit and test the starter motor. I need to modify my rear downtube panels (to hide the gubbins normally hidden by the airbox) and adapt a T140 type chain guard to fit.

CR carbs 2.jpg

Left: Brackets for oil cooler, horns and tank mount. Right Close up of tank mount and re-positioned fork stops.


Left: Rear mudguard supports and frame bracing and grab rail brackets. Right: Close up of rear master cylinder bracket.


A bit of a squeeze! Lots of wiring and components as well as oil pipe have to be routed. Different petrol tank mounting point makes things tricky.

fuel tank2.jpg
front mudguard.jpg
rear mudguard.jpg

Painted parts look great in SEAT 'LAVA' Blue.

rear mudguard complete.jpg
fork brace.jpg

FASTEC fork brace is a quality item.

rear view.jpg

Above left: Altered K100 inner plastic mudguard sprayed satin black and fitted to main steel mudguard. Above right: More modern style rear light looks to be based on the original Lucas type, only looks much better.

front view.jpg
left side view.jpg
Old pegs.jpg

'Modern' Hinckley footpegs look loads better than the standard rather ugly and heavy items (inset). Custom spacers are made from water cut alloy

needle roller tool 1.jpg
needle roller tool 2.jpg

Special tool for fitting gearbox needle rollers to exact location makes the job a doddle


Hyde half-race camshafts should complement increase in engine capacity


Due to it's sheer weight the engine will go into frame part-built

Exhaust mock up.jpg

Exhaust mock up. Pipes are too short so longer ones need to be fabricated, although there will be a complete new system eventually.

rear exhaust plates.jpg

Exhaust and passenger hanger template needs more work

rear plates.jpg

Special panels to fit to rear downtube

Modified brake pedal.jpg

Shortened rear brake pedal. Knurled footplate is from XJ750

starter motor.jpg

Starter motor ready to fit

Keihin 27mm CR carbs. Will need to source slimline filters