And yet another T120...

One thing I have seen done is two extra spark plugs fitted by angling them in on the insides of the combustion chambers. If you did that , firing each pair using double-ended coils off a Boyer, you would know when a plug died in service. The thing I mentioned about coke in the combustion chamber on the side away from the plug, I suggest is significant. There is a limit to how lean you can run the motor and it is set by reading the plug, but you only see the side which is near the plug. Around the other side of the piston crown, there must be a lot of mixture which does not convert to energy.

Fast Eddie said:

Did the service bulletin explain what was actually at fault, quadrant or cover?

Mine shifted fine with the 4 speed cluster in it. It would therefore make sense if it was the cover that was at fault, and someone previously filed down the 4 speed quadrant, so when I fitted a new one, I reinstated the problem!

Dave Degens used to set gearboxes up in an old case that he’d cut away. He then ensured the quadrant was indexing the cam plate perfectly before transplanting the cluster and covers into their cases. Cut away cases would have been handy to have on hand theses last few days!

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As far as I remember, the Service Bulletin refers to a certain batch of models from around 1969, and since it recommended filing the quadrant rather than the cover, it would appear that the former was the problem.

I am thinking of making a gearbox 'simulator' because from time to time I look at other gearboxes and I don't have any spare casings. I can elaborate on this if you or anyone else is interested.

Dave, you may be correct in your assumption, however, an alternative assumption is that filing the quadrant is easy for anyone with a file and a vice. Removing metal from the relevant area in the cover would require a specialist machining operation I think. Hence the factory advised the former...

Due to the fact that my own bike only created symptoms when fitted with a brand new 5 speed quadrant, made by LF Harris who use original drawings etc and used to build bikes, I suspect the cover as being at fault.

It’s all supposition though. All I know for sure is that it was one or the other!

Fast Eddie said:

It fired up first kick and a test ride showed the cam timing change has made a significant improvement and the 5 speed box has a very nice feel to it.

So... we got there in the end!

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And that's a great feeling, eh!

It is a great feeling indeed... while it lasts...

It seems the old kick start didn’t mesh too well with the new kick start gear. What I thought was compression, was in fact a jam, the ensusing hefty swing resulting in a clang.

I now suspect the kick start shaft to be bent as it’s not returning nicely, and it still jams occasionally.

What’s particularly annoying is that this scenario crossed my mind earlier, but I discounted my thoughts as being too OCD. I should have known better.

Another order has been placed at TMS for the suspected kickstart components and I impatiently await delivery.

Like I said already... two steps forward and one step backwards on this job...!

Strewth, you can’t knock the service of Tony and Martin of TMS in Nottingham, I only ordered the bits over the phone yesterday and they arrived today. Not bad is it? A random selection of gearbox parts for a 49 year old bike and you can get them that fast. I’d doubt it’d be quite like that even for a modern Triumph!

Anyway, new kickstart axle, quadrant and spring now fitted. New gearchange axle, quadrant, plungers, springs, guideplate fitted previously. Now you can call me an ‘old skool fool’ but I still use good ole Wellseal on most applications, I use a small brush to apply it, it’s a bit fiddly, but kinda satisfying.

Nailed back together this afternoon and, sun shone and the roads dried, so off we went for a blast.

With the cam timing changed, it just sounds ‘right’ now, really sweet and crisp.

The 5 speed Triumph box is just so sweet to use. I’m now wishing I’d bought my mates Nourish shell as I could have fitted one to the Commando!

Trouble is, the tacho doesn’t go over 3500rpm and the face of the speedo is shaking around, I also suspect it’s not accurate. I’m guessing they’re pattern clocks as I’m pretty sure it would have had a 150mph speedo and a 10k tacho fitted as stock, whereas it has a 120 speedo and 8k tacho.

After much deliberation, I decided to go for Smiths electronic clocks. I fitted them to the Trident Hunter and I think they’re well worth it. They’re just such a big PITA of a job to wire in. But yer gotta do wot yer gotta do... !

Fixed the cam timing by moving the gear one tooth - how accurate is that ? Have you got the cam spot at 4,000 RPM ? 'Sounding crisp' is not a measure of horsepower or torque. Have you ridden the bike yet ?

Strewth, you can’t knock the service of Tony and Martin of TMS in Nottingham, I only ordered the bits over the phone yesterday and they arrived today. Not bad is it? A random selection of gearbox parts for a 49 year old bike and you can get them that fast.

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Back when Richard Hacker did mail order from London, I phoned for a pair of pistons and 16 hours later I had them.

That was to the north of Scotland, which Google maps now says is a 12 hour drive.

acotrel said:

Fixed the cam timing by moving the gear one tooth - how accurate is that ? Have you got the cam spot at 4,000 RPM ? 'Sounding crisp' is not a measure of horsepower or torque. Have you ridden the bike yet ?

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Please read the thread before asking pointless, irritating questions.

Triton Thrasher said:

Advancing the inlet cam improves low and mid rpm power. If it's been a tooth retarded, you will notice an improvement.

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TT, are you sure about this? It doesn’t feel like it’s the low and mid rpm that’s improved. It’s the upper rev range that’s changed. And by quite a lot I think.

Unfortunately I can’t be very objective as the tacho doesn’t work! The new electronic Smiths one arrived today, along with the new speedo, I took them down to the workshop to make a start at fitting them but, it’s a big job, and the sun was shinning, and the roads were dry, and the missus and kids had gone out... so I went out for a blast instead !

Fast Eddie said:

TT, are you sure about this? It doesn’t feel like it’s the low and mid rpm that’s improved. It’s the upper rev range that’s changed. And by quite a lot I think.

Unfortunately I can’t be very objective as the tacho doesn’t work! The new electronic Smiths one arrived today, along with the new speedo, I took them down to the workshop to make a start at fitting them but, it’s a big job, and the sun was shinning, and the roads were dry, and the missus and kids had gone out... so I went out for a blast instead !

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No two engines are the same, but late closing of the inlet valve is good for high rpm running, when the inlet charge is carried into the chamber by momentum or inertia. At low rpm, late inlet valve closing allows the piston to push mixture back out through the inlet tract, from BDC until the the inlet valve closes.

Thanks TT. I’ll post some more objective feedback as soon as I have a functioning tacho...

When are the Fontana brakes arriving ?

I suppose it must have been so far retarded that you were losing power everywhere in the rev range.

trident sam said:

When are the Fontana brakes arriving ?

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Cheeky...!

So far at least, the TLS front brake has surprised me with its performance...

Got the digital tacho on and wired up nicely. Speedo is on and nearly wired up then ‘work stopped play’ for a few days.

Sender unit and wiring next.

I like these digital Smiths clocks a lot, but boy oh boy, it’s a job and a half fitting them !

Well, well, will wonders ever cease? I finally finished fitting and wiring the bloody electronic clocks!

Muchos gracias to Tom Kullen for his modified speedo drive housing and purpose made reluctor, I bought it a while back for the Trident Hunter but didn’t use it. Came in handy eventually though!

It’s SO nice having steady and reliable clocks, especially the tacho.

I can now report that the engine tone changes to a crisp rasp at 4K and then pulls really nicely to 6k. Its clear it will pull to 7k and beyond if asked, but it feels like power peaks at around 6k to my ass, and changing up still sees the motor smack bang in the crisp zone again (5 speed box remember).

I also experimented by moving the breather and plumbed it into the TDC finder hole. I thought I’d get oil out of it, but not so, works well (probably aided by the reed valve).

Drive side of a Triumph sure looks cleaner sans tacho drive (see pic). You can see the re-sited breather in the pics too, and, of course, the new clocks.

And, I’m sorry Sam, but the pancake filters are back on the shelf cos I saw these lovely short ‘she-mozzles’ on LP Williams web site and couldn’t quite resist!

A nicely sorted Triumph sure brightens up your day !!

The bike looks great Nigel, and I'm sure Mr. Shemans would have approved of your nozzles !
How does it compare to your Commando ? are you going to get it dynoed ?
Surely now you must be considering getting rid of that German thing and buying another real bike

Thanks Sam, I’m thinking of calling the Bonnie the ‘Commando Hunter’...!

Seriously, it’s no where near as quick as the Trident Hunter, I’d guess it’s got something close to 50rwhp.

What I really like about it is that is so light, and easy to manhandle and easy to start and easy to flick around and filter through traffic etc. Remember that old Triumph add “It’s easy on a Triumph”? Well that kinda sums it up. It’s basically my ‘go to bike’ for general local use.

The German thing, well yes, I do have another project on the go that should hopefully hit the road next summer, that, when dialled in and sorted, may well bring in the departure of the Panzer.

Fast Eddie said:

I can now report that the engine tone changes to a crisp rasp at 4K and then pulls really nicely to 6k. Its clear it will pull to 7k and beyond if asked, but it feels like power peaks at around 6k to my ass, and changing up still sees the motor smack bang in the crisp zone again (5 speed box remember).

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Sounds like you've got yourself a good running Triumph.