Triumphrat

baeckel

Are there any good ways to date a triumph without having an engine number to go off of? The engine number has been replaced with what I believe to be a social security number (apparently you can/could get a "home made" motorcycle title this way).

I have it somewhat narrowed down: It has MK1 concentric carbs so it should be after 67, and it is not an oil in frame model, so it should be before 71. There is a "68" stamp on the head... I'm not yet willing to use this number as a date. Are there any dimensions of engine parts or something that I could measure to determine the year of my bike? Is there something unique a specific year between '67 and '71 that I could look at/for?

Thanks for any help!

--Jonathan

TxTiger

There should be a VIN number on the frame that wiil date you frame. I think on a duplex frame it will be on the part of the frame below where the front forks connect to the bike.

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'71 Tiger

rmak

Don't really have constructive input, but I got a laugh out of the title. My wife calls my bikes my "mistresses" so in a sense, I am dating a Triumph. Actually three. Is that a menage-a-trois?

TxTiger

Only if they leave you out, otherwise it's a menage-a-quad

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'71 Tiger

t100rc

Post pics ... that should help ...

In '70, they added a breather to the inside rear of the primary.
In '69, the tach drive threads went left-handed.

We can come up with more year-by-year changes to help with dating the engine by way of elimination.

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RC
'70 T100
'56 T110 (in progress)
Crossroads Cycle

rmak

I thought that was when you're dating an ATV!

Webby

Hi Baeckel,
There are a few ways of figuring out the year of your bike. As has already been mentioned check the number of the frame.

For the engine, have a look at the following:

The date on the head should be the casting date, so there is a good chance the rest of the engine is 68 or 69, however a head is very easy to change.

Gearbox Plunger, have a look under the bike and you should see what looks like a large bolt about 1" long, if it is there your engine was built before (I think) mid/late 70.

Crankcase breather, if you have a large breather tube (about 1" diameter) coming out of the primary case your engine was built after 69.

Alternator wiring, if you have your alternator wires coming out of the top of the primary case your engine was built after 69.

Please note, the dates are approximate, let us know what you find and I'll get back to you with more exact dates, engine numbers etc.

I hope this helps

Webby

jimmy bush

The crank breather and exit for the stator wires were relocated from the bottom of the engine to the top r/h side of the primary in 69 and subsequent. The 1/4" rocker box bolts and I think the cover screws went from fine thread to coarse in 69 (and later). My books show the 67 with monoblock carbs. If you have the concentrics carbs, fine threads on the rocker bolts, lower breather and alternator wires, it's probably a 68 unless the carbs have been changed out (in which case it could be a 67). Coarse rocker box threads and top exit for breather would be a 69 or 70. The carbs were secured to the adaptors (the spigots that screw into the head) with nuts and bolts until 69 when the bolts were changed to pressed in studs in the adaptors. There was a phenolic insulating block between the carb and intake adaptor on the 68 and 69 that is not shown in my 70 parts book. I don't know if this was or was not on the 70's. The 70 frame had two removeable triangular plates that bolted to the frame for the front engine mount, 69 and earlier were welded solidly to the frame. The 67 did not have a removable timing cover (round cover with 3 counter sunk screws) in the primary cover. 68 was the first year for that. 67 had a single leading shoe front brake. 68 had a twin leading shoe brake that had the cable running straight back along the lower fender brace. 69 & 70 the cable run up along the fork leg. I think the 68 & 69 had grab rails that bolted to the bottom of the seat. It caused the seat pan to crack so they changed it to bolt to the shock mount and rear fender in 70. the lower forks for the 68 & 69 had threaded bosses welded to the inside of the fork for the front fender brackets to bolt to, the 70 had a cage with a captured nut that floated inside for the brackets to bolt to. There are other differences that don't come to mind but this should get you started. Keep in mind that a lot can be changed in 40+years so later parts could have been grafted.