Triumph PreUnit oil line supply -to- gauge?

[TechNoir]

The rockers need to be fed from the scavenge side of the system just as yours is already. The 1938 and 1939 twins had them fed from the high pressure side but had to use a restricter to cut the oil pressure and volume down. The bottom end needs high pressure but the rockers just need a trickle of oil so it makes much better sense to feed them from the return side of the system. Triumph only did it from the high pressure side for 2 years and then changed it to the low pressure side and kept it like that for decades.

I will have a look at parts suppliers over the weekend for you if you like. Trisupply (Oliver Barnes) and Ace Classics in the UK will certainly have the parts even if they are not listed on their websites. There are two types of domed nuts, one with a slightly longer dome than the other. My pre-war twin takes the longer one. I am not sure what year they changed it to the shorter one but the guys at Ace Classice will certainly know.

The Banjo is just a standard part to suit the diameter of the stud. The pipe is standard size oil pressure gauge pipe, your best bet is a Mini spares supplier (thats Austin Mini or Morris Mini, not the BMW Mini). You will need a fibre washer to connect to the gauge, the Mini place will sell them.

In 1938 the oil pipe was in one piece from the feed to the gauge making it difficult to connect and disconnect it when taking the tank off. In 1939 they added a joint just below the tank (see my picture) to make it a much easier job. I assume that your bike has a similar arrangement although I am not familiar with the exact details on the post war bikes.

John

[sprangerny]

Many thanks for all the info. So many questions on a new vintage of bike. You guys are amazing. Sorry to bug you, but three other questions: 1.) I'll bet someone out there will know if my Headlight Lens (original Lucas?) is orientated in the correct direction? I can only assume it's correct, since the LUCAS lettering is stacked vertically. 2.) does anybody know if a brake light switch, and 2 filament bulb, was ever standard on a 1948 T5? and 3.)
would the KNN 459 plates be original, or from a known county in the UK? IMG_20171119_164223901.jpgTailLight.jpgPlateSide.jpg

[TechNoir]

Hi sprangerny.

I dont have much time now so if no one else chimes in I will post an update tomorrow.

1. In the UK we drive on the other side of the road to the USA. Looks like a UK spec bike to me so its correct for the UK. However loads were exported to the USA so there must be a USA spec light available to point it the other way.

2. Not sure for a 48. I will have to check my reference books to see when the brake light/dual filament was offered which are in my shop and I am just about to go to bed (22:35 in the UK right now)

3. Looks like a standard 1948 UK plate to me. There are some on-line resources that can tell you more.

John

[Rubone]

The Cateye lens orientation is correct. The taillight isn't however. The shotglass light did not yet exist in '48 but many were updated along the way as the lens assembly fits the old MT110 light base. The stoplight was an accessory I believe. The switch would mount on a plate bolted on the left peg/muffler mount and attach to the brake pedal.

[AFJ]

Many thanks for all the info. So many questions on a new vintage of bike. You guys are amazing. Sorry to bug you, but three other questions: 1.) I'll bet someone out there will know if my Headlight Lens (original Lucas?) is orientated in the correct direction? I can only assume it's correct, since the LUCAS lettering is stacked vertically. 2.) does anybody know if a brake light switch, and 2 filament bulb, was ever standard on a 1948 T5? and 3.)
would the KNN 459 plates be original, or from a known county in the UK? [ATTACH=CONFIG]21133[/ATTACH][ATTACH=CONFIG]21134[/ATTACH][ATTACH=CONFIG]21135[/ATTACH]

On a 3 letter/3 number British "Registration Number" the second and third letter indicate the County, Borough or city of original registration for the motorcycle or other powered vehicle. "NN" indicates that the county of Nottinghamshire was where the registration number KNN459 was issued. Likely it was to the Triumph. There were a few situations where a vehicle was being scrapped and the owner of the new vehicle transferred the registration number to the new vehicle but if a vehicle was being traded in or sold used, the registration number stayed with it.
If the tail light was originally an MT110 with a single filament, replica MT110 tail lights which have a stop and tail bulb and wiring are available. I fitted one of these, but also have fitted a much larger and modern stop/tail lamp to my late 1930's British bike - car drivers do just not see these small old types of motorcycle tail lamps.

AFJ

[sprangerny]

Many thanks, guys!

[TechNoir]

A small addition from me. AFJ has clarified the registration number and Rubone has commented on the light which originally would have been a Lucas MT110 (I wasn't sure, my 5T uses an MT110 but I wasn't sure when it changed)

The best reference book to get for a 5T is Harry Woolridge's book called simply: "Triumph Speed Twin" and sub-titled "The development history of the pre-unit & unit construction 500cc twins"

The MT110 tail light was used up to the 1950 model. For 1951 it was changed for Lucas part number 53216A which is of a "tapered construction for a larger reflective area" but still no mention of a stop light.

For the 1953 model the book states that "A new Lucas Diacon plastic stop and tail lamp, part number 53269A, was fitted. Operation was via the rear brake rod through a spring, with the Lucas stop switch being fixed to a plate anchored to the pillion footrest bolt."

For your bike, 1948, there seems to be some slight variations through the model year. the books states:

"For 1948 no engine changes took place but during the season year several changes took place to the motorcycle parts. Due to circumstances outside the companies control these changes could not be introduced at the onset of the season but were brought in as and when convenient."

Therefore your bike could have none of the changes for 1948 or all of them or just some of them.

However one item that I notice on your bike is described as:

"Rear Number Plate
The rear number plate top portion was reshaped to provide a hand hold whilst using the rear stand. This was made necessary by the deletion of the two side handles fitted to the earlier rear mudguard"

Your bike would also seem to have the updated rear mudguard

I would recommend Harry's book to any 5T owner. Harry worked at Triumph for 30 years and his book is one of the more reliable sources of reference.


If you wish to retain an appearance close to original then there are a few MT110 replicas available some with a single filament fitting and some with dual filament fittings although a lot of them are poor quality. The best ones that I have come across are from this company:

http://www.vintage-replica.cz/svetlaE.htm

They are more expensive than the others available but the quality is in a different league.


John

[sprangerny]

You have confirmed my faith in all things British (assuming that's where you are located?). Printed out ALL of your insightful comments and read them several times - will be my addendum to Harry Woodridge's book, when it arrives!!

[TechNoir]

You have confirmed my faith in all things British (assuming that's where you are located?).

Thanks, I am in Britain, Blighty = Britain.

Re the faith in British. It is my experience on this forum that there are LOADS of helpful people from all over the world. I think we all subscribe to the principle that you reap what you sow. If I need help I know that quite often I can get it on here. Likewise if someone asks for help and I can provide some then I will do.

John

[sprangerny]

Figured that. Been to your side of the pond many times!