Pre Unit Triumph advance/retard

[Rob Farmer]

I need an opinion please gents.

This is Jim Elderfields Pre Unit Triumph Advance/Retard Unit. I haven't come across one of this type before. There's no spring mechanism at all just 5 rollers that fling out advancing the mechanism, working it by hand they don't return at all just staying fully advanced.

Recognise it or have any ideas?

 

[Coolcarbon]

Just had a chat to a mate who had a Tiger 110 for many years...

He remembered the fact there was no manual timing adjustment, it just happened automatically....

He couldn't recall there being any spring(s) in amongst that lot either...

That said, he's lost a lot of Brain cells since he owned that bike through copious amounts of falling down liquid so could be a wee bit befuddled...

 

[Rob Farmer]

Thanks for taking the time to ask him CC,

The conventional Advance/retard is sprung loaded and operates as any conventional points unit does (piccy below). I've had bikes with manual advance/retard as well but I've never come across a unit like the one on Jims bike.

 

[Coolcarbon]

Yep, an odd one...

My A10 BSA had manual adjustment and my T150 had been changed to aftermarket electronic system when I bought it...

Don't suppose magnetism could be involved to return the weights, sounds daft, but then there were some seriously daft things oot there....

Nah, that is daft....how about.....cover them in WD 40, that'll fix it....

Sorry, I'll get me Waxed Mackintosh...

 

[Rob Farmer]

Jims given me a pile of the conventional units along with a BTH mag so its no problem to fit one of those. I'll whip this one off and see if I can get an ID on it.

 

[Coolcarbon]

What model trumpet is it..?

 

[Rob Farmer]

Its a Triton.

Pre Unit 650 with 9 stud twin carb head. Its been really well put together and clearly hasn't been run since it had a rebuild. Jims had it laying around for a long time and just wanted it checking out.

I've pulled the head off today - these are the pistons as found.

 

[Shep]

Its a Triton.

Pre Unit 650 with 9 stud twin carb head. Its been really well put together and clearly hasn't been run since it had a rebuild. Jims had it laying around for a long time and just wanted it checking out.

I've pulled the head off today - these are the pistons as found.

Piston reversed, that was put together by a quality builder then

With the Mag advance and retard I had one like that (a long time ago) on a bike running a BTH mag, not much help to you though as I can remember nothing about the set up, sorry. But it may be specific to the Mag

Shep

 

[Rob Farmer]

Shep,

It's the reflection on the left hand piston that makes the valve cutaway look bigger. Both pistons are in the right way .

The mag fitted is a Lucas K2f. I have the BTH in a box. Thats probably a good clue though

 

[Shep]

Still looks different, even now you've told me

The Triumph I had, with that advance/retard unit on, was a real bits and bobs bike, pre-unit 750, supercharged, norton crank, steel rods, stupid cams, running on a rich Nitro/methenol mix, it was like riding a hand grenade I had 1/2" thick alloy plates on top of the head and another across the sump on the specially welded cases with 4 x 1/2" HTS steel studs squeezing it all together, in the hope of getting more than 1 meeting out of the engine

In truth it rarely got past the first run of the day without terminal failure of some form. A real money pit

Anyway, bits came to me from everywhere hence the recognition of the unit but no recollection of where it came from.

Shep

 

[(RIP) Kaister]

he - he - he....its leaking oil already and it hasn't run yet...

 

[Rob Farmer]

he - he - he....its leaking oil already and it hasn't run yet...

Jims coming over to Aus again next week so I wouldn't take the piss too much

Just found the piston rings have siezed up

Lovely polished and balanced crank and conrods though. enourmous cams (probably spitfires) and R radius cam followers. should be nice and torquey and quick off the line

 

[(RIP) Proff]

Jims coming over to Aus again next week so I wouldn't take the piss too much

Just found the piston rings have siezed up

Lovely polished and balanced crank and conrods though. enourmous cams (probably spitfires) and R radius cam followers. should be nice and torquey and quick off the line

FFS Rob, just soak the pistons in Diesel, they'll free off in a couple of days.
I always use "Graphogen" for building engines
It's that good I've even started and run engines for 3 minutes [@2000/3000 rpm] without OIL after rebuilding with it [beds them in lovely] you can race them straight away no further running in required


Another advantage is, if you ain't using engine right away, it keeps it all free and ready to run..
I've left a BMC MGB 1800 engine for 10 years in 70's, installed it and it started and run perfectly. last I heard it was still going strong 10 years and plus 50.000 miles later and no other engine work has been carried out
a useful linky
http://www.graphogen.co.uk/

 

[Rob Farmer]

I bought a gallon of diesel at lunch time just for this purpose Proff

A mate freed up a Citroen DS engine using coke. Never tried it myself though.