Wednesday, December 28, 2011

Oil cooler subframes, large and small

The 1991 Triumph Trophy 1200 is fitted with an oil cooler, in common with all other faired models. The first models were all fitted with the same cooler - a 9 inch wide, 5-row aluminium radiator with fittings for banjo bolts. Some time in 1992, the factory started fitting larger versions to the 1200 models - a 10-inch-wide, 7-row radiator. This required a larger cooler subframe.

5-row subframe on the left, 7-row subframe on the right
This post shows pictures of the two cooler subframes next to one another (along with a variety of old engine gaskets pending replacement!). Triumph also changed the oil lines so that the banjo fittings were positioned on top instead of underneath the radiator. I suspect this decision was to protect the fittings from corrosion because muck accumulates on the lower edge.

7-row cooler subframe
5-row cooler subframe

The later subframe has two angled brackets on the top edge, the angles to make room for the top-mounted oil lines.

With the 5-row subframe on top of the 7-row subframe,
the size difference is clear
I want to preserve as many of the fittings of the original bike as possible but think the larger radiator is a good idea. My bike had been running hot when I rode it home. I intend to try fitting a 7-row radiator from a later Sprint 955i into the smaller frame. I've got some ideas on how to do this. 

Thursday, December 1, 2011

Cams and cam chain tensioner

The cams were in beautiful condition - the lobes were factory fresh with a mirror finish. There was a lot of white silicon sealant around the cam box. The manual advises to use it on the two end sections. Cleaning it off was fiddly - I have a single-edged razor blade for the purpose.

The cam chain tensioner is a spring-loaded plunger that bears against a reinforced section of a rubberized blade. The first 1200s had a metal plate fitted to help position the blade against the blade. I imagine there were some problems with this because the manual advises that it should be removed. 

Cam tensioner unit is visible in lower right corner of the blue box.
The problem metal plate is the cadmium plated part that is
visible around the plunger 

I tried refitting it at first to understand what the issue was. It was tough to get it around the blade because the rubber had swollen. 

The end of the camchain tensioner is visible in the center

Carbs and filter

The carbs were in good shape overall - just a bit of muck in the float bowls and the needles were muddled up (the inner two are a pair and the outer two are a pair).

The code for original 1200 carbs is visible on the side: 1240010. 

Other than the swapped needles, the only other problem was corrosion on the float bowl mating surface, visible as white powdery substance, which lead to a fuel seep. 

The airbox had cracked had been taken apart before and badly reassembled. The box-to-carb rubbers had been refitted upside down. This is visible in the picture to the right as an inlet ribbed section at the bottom of the rubbers. These should align with air pressure equalization apertures on the top edge of the CV carbs.  
The box had also failed on the lower edge where the two halves screw together. It is not designed to be disassembled - when the air filter is passed its service limit, the idea is to swap in a whole new air box complete with new filter. However, the fact that is screwed together rather than glued or plastic welded means it is possible to remove and clean, or replace the filter with an aftermarket part. I read somewhere that the original filters were made for Triumph by PiperCross. They are available on eBay.  Lots of people replace them with K&N filters though. 
Airbox disassembled - note ragged side on lower left-hand edge.
This is where the plastic had failed, probably by over tightening.
I chose to clean my filter and to repair the splits by welding them up with a bit of plastic filler rod and a soldering iron. I also drilled holes for a through-bolt either side. I made this up from stainless rod and a couple of stainless domed nuts locked up against regular hex nuts on the inner edge. 

Tuesday, November 8, 2011

Alternative oil cooler for Trophy 1200 from Sprint RS 955i - Part One

Although I put a lot of effort into cleaning up and painting the original five-row cooler, I am not sure if the oil couplings will hold so want a spare on hand in case they leak. It's not easy to find second-hand coolers in good condition, even though they were fitted to all the faired 900 models, because they are mounted low behind the front wheel and so are vulnerable to attack by grit and spray. On top of that, the 1200 Trophies were given larger seven-row coolers some time in 1992 because they run hot in traffic. I thought it would be as well to do something similar. 

Both early and late coolers are mounted via banjo bolts and so can be plumbed in. However, the seven-row cooler is mounted with couplings on the top edge whereas the five-row cooler is mounted with couplings on the bottom edge. As a result, the later 1200s have much longer feed and return pipes. Also, the subframe for the seven-row cooler is considerably taller and has different brackets for fixing the cooler in place. Some inventiveness would thus be required here. Just my thing!  Unfortunately, these large coolers are hard to find now and prohibitively expensive new. Fortunately, after looking at lots of other Triumphs I think I found a partial solution in the form of the cooler fitted to 2000 Sprint RS 955i. 

The 2000 Sprint RS 955i is also fitted with a seven-row cooler via banjo bolts and has a similar width to the 1200 Trophy. It is also mounted at the bottom edge. The 955i is a more recent model parts are still in plentiful supply in reasonable condition. The bolt holes for mounting it are different however so a special bracket would be needed  - something I'm comfortable doing. The photos show how that the Sprint cooler is taller (by about 1 1/4 inch), wider (by about 1 inch) and thicker (by about 1/4 inch).

The original 1200 feed and return oil pipes fitted with replacement rubber sections and temporarily bolted in place on the Sprint RS seven-row cooler.

Sunday, October 30, 2011

Welding captive nuts and filling holes on the frame

The rear subframe had a few holes drilled in it for unknown reasons (but probably alarm related) by previous owners. I decided I disliked them sufficiently that I should try filling them with weld. 

There was a large diameter (c. 13mm) hole in a cross-brace with the VIN plate and a small hole next to it, probably for a self-tapping screw. I scraped off the sticker then ground the rust from the hole perimeter with a mini grinder. 

 Next came the MIG work. It went pretty well, carefully adding bead to bead with enough time to cool between each burst to stop the whole thing from dropping through. It only needed a few seconds between each bead for this. Finally, a flap wheel on an angle grinder restored the level of the material. There are a couple of little imperfections in the surface but rather than risk sorting them with more weld, I decided they'd fill with primer easily enough. 

The other welding I needed to do was to restore six captive nuts that had split away from the frame. Three were M8s for the exhaust mounting brackets, two M8s for the grab rail and rear fairing panels, one was an M8 for the left-hand rear indicator bracket, and one M6 for the right-hand rear fairing panel. The mini-grinder came out again to get enough shiny metal for me to weld to. This was very tricky as it turned out because of restricted access to all but the M6. In each case, I wound a bolt tight into the nut to ensure there was good electrical contact, then welded some wire into the frame near it, running up to the nut itself.

A captive nut - that's captive again!
Rear subframe after all welding
and grinding was complete.
Finally, I used a wire brush on a drill to bring all the rust off where it had developed. In most cases, these places were on factory frame welds, in the others it was nicks and scratches. I finished up with zinc primer, pending rubbing back on main spar sections and a coat of black.

Rear subframe after derusting and priming

Tuesday, October 18, 2011

When the Trophy 1200 hit the roads in 1991

When the Trophy 1200 hit the roads in 1991, it was a surprise to just about everybody. Part of the surprise was left over from the astonishment of the Cologne Motorcycle Show in September 1990, six months earlier. 

Pre-production Trophy 1200 as Exhibited at the
Septermber 1990 Cologne Motorcycle Show

The paint and graphics for all models were revised following comments from show visitors and potential customers to the form they would retain until 1993. 


Journalists struggled to believe it wasn't just another myth or financial stitch up, that the motor would stay together without leaking oil, that there would be any engine-chassis combination that could work in a satisfactory way. There was a huge credibility gap for John Bloor and the likes of Bruno Tagliaferi and Gary MacDonald to fill.

The Daytona 1000 received a tepid response from the press at the time, though the passage of time allows a more sympathetic understanding of its virtues than the super-sports image permitted bay then. The Trophy 1200 amazed just about all the journalists who wrote about it for the urge available from its engine, positive and stable ride quality and general standard of finish.The Trophy 1200 filled the gap in a way that did proper service to all their careful planning, designing and development work. Inevitably, when looking back at journalists' statements about relative power twenty years ago, some read now as pure hyperbole couched in terms of the expectations of the day. Gazelles also may have moved differently in the early 1990s. However, the excitement and balance of the package are as clear now as they were then. 

Motorcycle News, March 1991:
"Since the engine is the most demanding piece of engineering in a motorcycle, the brilliance of the 1200 comes as the biggest shock. Power is everywhere ... at low rpm the sense of latent power is colossal, there's never any need to wait for the motor to gather is forces. ... The motor has more grunt than a charging rhino on speed but the chassis and tyres give the agility of a gazelle - an almost magical combination still rare even in todays' high-tech bike industry, and unheard of in connections with any british roadster."

Bike Magazine, May 1991:
"From 4000rpm, there's phenomenal, exhilarating urge that, thanks to the pari of gear-driven balance shafts in the sump, is honey-smooth up to 6000rpm, an id growls through its Motad stainless four-int-two pipes beyond that. A fearsome growl like no other. ... Taking the package as a whole, the plusses are massive and reek of well thought-out professionalism. ... It's not at the cutting edge of technology, there's no gimmicks, no upside-down forks and no fancy aerodynamics. But it is a damn fine bike powered by an astonishingly lusty, zestful engine."

Fast Bikes, June 1991
"Triumph motorcycle company have produced a bike that is not just good, it ... may be the best sports-tourer ever. [it has] a mighty furnace of free-flowing, unending power that pours forth with the continuity and inexorability of molten steel ... It hauls you to 100 on the merest tug of the throttle where the crank is spinning at a lowly six grand, yet it can pull away in top from the hundreds and fill its lungs as quickly over three figures as it does when you let the remarkably precise and glitch-free clutch out at a trickles. 'Torque-line' may be more appropriate than torque curve, as it just keeps on getting stronger all the way from 4000rpm to 8000rpm with no perceptible peaks or troughs. ... There is an almost perfect harmony of stance with the level of rake afforded by the screen an d fairing an d the Trophy is as capable of devouring peaceful, angst-free miles as any of the standards of sports-tourers."

A year or so later, the factory had gained confidence and was prepared to make bold statements about what it was about, where it had come from, and the values that would carry it forward. The Building on a Heritage video shows that Triumph still had a job to convince people they were for real. The format and accent of the narrator also shows how long ago it is now that this resurgence happened, underlining the historical significance of the relaunch in its own special way.

"The public at large could be excused for not appreciating that the current range of Triumph motorcycles was conceived, designed and manufactured in Britain. What also gets overlooked is the fact that it was the result of a decade of painstaking research design and development, building on a heritage."

Monday, October 10, 2011

Fuel tap rebuild

My fuel tap on my 1994 Daytona refused to turn off - petrol poured out regardless of tap position. The tap has three positions - on, off and prime. On and off are supposed to be controlled by a vacuum operated diaphragm that pulls a valve open when the engine is running. Prime holds the valve open via a cam in the tap so is the only position that should let fuel out of the tap with the engine off.

Triumph fuel tap knobs from 1994 (left) and 1991 (right)

I managed to break the plastic knob (left in picture above) when I was removing it. I had the 1991 Trophy one so could use it for the time being. The plastic knob engages with the aluminium fuel selector casting through a flat cast into its circular recess. This flat was the part that broke on the 1994 plastic knob. The 1991 one (right in picture above, with a chunk of cosmetic plastic missing) has the flat 90 degrees from the 1994 version, meaning the visible pointer on the outside of the plastic knob does not point down for reserve, back for on and up for prime. Instead, it points forward for  reserve, down for on and back for prime. 

Rebuild kit from Sprint Manufacturing
Extracting tap from tank
 I got a tap rebuild kit for £24 from Sprint Manufacturing.  It includes two new springs (one to hold the diaphragm closed when the engine is off, one to keep the selector valve in tension so it returns from the prime position), four new screws, a diaphragm, a rotary oil seal and two shaped rubber grommets to seal the tap body against the tank.
Fuel filter housing separated from
fuel selector body

The body of the tap is held on to the tank with two long M6 screws that pass through the selector housing and fuel filter housing to engage with captive nuts.

Fuel systems don't like grit so it's important to have somewhere clean to do the job. I have an old set of stainless steel camping pans for jobs like this.

Vent hole (indicated byscrewdriver
tip)  to allow diaphragm
to pull valve out when the
engine is running. 

Removing diaphragm housing,
diaphragm valve closing spring
visible in the centre of the picture
The diaphragm is housed in a chamber at the rear of the tap. The cover is retained by four M4 Philips screws. It is likely to pop off under the pressure of the larger of the two springs in the tap body - get ready to catch it when it goes. 

There is a vent hole at the bottom of the diaphragm chamber, behind the fuel selector mechanism. I think my problem was probably dirt ingress through this vent hole interferring with seating of the diaphragm valve. 

Aluminium plunger with o-ring
under diaphragm
Diaphragm valve seat location
The diaphragm is actually two diaphragm components that attach to an aluminium plunger with an O-ring at one end. The two diaphragms fit either side of a plastic collar. There is a hole in the diaphragm that locates over the vent hole - a raised bump in the plastic collar helps to make sure it is round the right way on reassembly. 

After pulling the diaphragm housing apart, it was very clear that dirt certainly could have been responsible for the problem. So a thorough clean was required. 
There were traces of corrosion in evidence too so it carefully (there's a word) rubbed the sealing surfaces back with wet and dry on a foam sanding block.
I used silicon grease sparingly on the sealing surfaces, eased the new diaphragm into its plastic collar then, checking that the vent holes were aligned, installed the new spring and tightened down the M4 screws. 

Cleaned and ready for reassembly
New (left) and old (right) diaphragms
Installing new diaphragm, making
sure the vent hole is aligned to the
matching hole in the new diaphragm

The fuel selector is made of two parts, one an aluminium casting and the other a plastic component that it turns inside the top body. The aluminium part is held into the tap body by two screws. These screws have plain ends that fit into a track that is cast into the ally selector - they twist off centre to force the tap in when turned to the prime position. This is actually what makes prime work because a long steel rod pushes through the centre of the tap onto the diaphragm valve when this happens, thereby pushing it open.
Removing fuel selector retaining
With retaining screws released, the
fuel selector is pushed up by the small
screw on the prime operating rod
and can be lifted out. 

Fuel tap selector with new spring in
place and about to smear with
silicon grease before inserting back into
the seal in the selector housing.

Fuel tap selector back in position,
ready for pushing back against
spring tension to install retaining screws.
Note the prime cam ramp is just visible
by my finger. 

Fuel selector pushed into place and retained by screws.
The fuel selector positions are cast into tap body - these make
sense with the 1991 tap but don't match up for the 1994 tap

Rebuilt and ready to go.