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#796497 01/24/20 10:03 pm
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Was the spark arrestor fitted to some bikes, for the USA models only? ie was it fitted to UK and General Export models. Handbook for latter models seems to show without, but there does not seem to be a corresponding UK/GE version of either years parts lists. All "USA Edition".
The bike I owned in the eighties which was delivered new in Australia. did not have any add-ons to the exhaust.
And does anyone know anything of the suitability of the Domiracer Nippon Seiki speedo as a parts donor for the "Triumph" version?
Phil

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No first hand knowledge but afaik spark arrestors were a USA thing? Possibly even west coast?
Not that I have huge historical knowledge but the first I remember of them was reading the Internet where I was exposed more to USA bikes
There may have been references in the odd book before, but I don't remember that

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Hi Phil,
First of all--welcome to the forum--- I hope that you find it useful and interesting.
I live in US and have a 73 and a 74 Tr5T.
I believe that the spark arrestor was fitted only to US bikes and was necessary for the bikes to be used on forestry trails in US.
There was a sticker placed on the muffler of bikes destined for US (photo attached).
We believe that the sticker was applied at the factory in Meriden.
We further believe that the spark arrestor was fitted in US--either at the distributors or at the dealers---probably the distributors we think.
FYI we are working with a TR5T enthusiast in UK (Andy Burbidge) to get new stickers printed as in the photo.
BTW--does your muffler have such a sticker on it?---or perhaps you can see where a sticker was from the old adhesive patch still there?
Sorry I cant help you on the speedo front.
HTH

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Supporting Tridentman, my 73 NZ new TR5T appears to still have the outline of the sticker on the muffler so maybe it was automatically fitted to all bikes.
I will be interested in those stickers when they become available.


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Tridentman has been a great resource on all things TR5T. His bikes are USA east coast, and mine is west coast and all have spark arrestors. Additionally mine has the remains of the sticker still present after 6000 miles and 47 years. I guess Meriden used good glue!

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J R krizman was an American inventor responsible for the krizman brand of spark arrestor .
His company made "non-restrictive" Spark arrestors and he also licensed his patented ideas to most
of the major brands with off road bikes by the early 70s
the vanes deflect bits of carbon ( hot Embers ) into trap areas
so they are not-spit-out with the main-exhaust stream .
the u.s. Forest Service has had some form of spark arrestor law in place
Since about 1905 ... they got serious about small engine Spark arrestors
used on federal land in 1968 (SAE Standard J335 ) .
... I'm guessing it was a U.S. only thing back in the early 70s ?

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Interesting... though the pictured example does not have one fitted.

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Thanks for a great array of responses. I don't have the bike. I had one in the mid eighties. I am looking for one now as a retirement bike, smaller and lighter than the Hinkleys that I have been riding for the last twenty years. I have a couple of bikes that I hung on to from those eighties, in bits. A T25T, an A65SmkII. I'm gradually changing over. So far a T65 BSA, (rebadged TR6R Triumph) which took me a year to find, but the one I really want is the TR5T. If I can't find one I may have to go for a TR7T, not ideal but probably more saleable for my descendants when they clean out the shed.
I do have some parts left from the previous ownership, just in case. One such is the original muffler. It has no sticker Or no part number stamped that I can see, but it does have a long tail pipe; approx seven inches from the body to the tip. And the tip is slotted as if to take a finisher secured with a clamp. I kind of remember my bike had the "tip" when I changed it over with a new one, but it was a long time ago.. One of the reasons I'd like a "home and general export" version of the parts book. My USA parts books, the yellow 73 and the orange 74 series 1, both show the muffler with a short "stub".
Is anyone able to comment on the instrument question?

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The long stub muffler is the second design. Sorry can't help with your speedo question.

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Phil--is there any residual sign of the adhesive from the label on your muffler?

I agree with Bob (who is a good friend and close neighbor of mine).
In the 74 parts list the muffler has a different part number than in the 73 parts list.
The difference is that the 74 muffler has a tail pipe about three inches longer than the 73.
There are quite a few of the 74 bikes that were fitted with the 73 muffler so it looks as though the changeover was a running change during the 74 model year.
Bearing in mind the turmoil and chaos in the factory at that time I guess they carried on using the 73 mufflers into the 74 model year until they ran out and then starting using the 74 muffler.
Or perhaps even more chaotically they just used whatever came to hand on the assembly track at the time.

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There are a lot more tr5t's than tr7T's

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Tridentman - I think the change happened earlier than what you state. If we take the "long" exhaust terminates by the wheel axle and the "short" one about 2" in front of the shock absorber bolt, then I think the change happened just after model release in 73 build year. The lebgths are without the spark arrestor on. The publicity photos for 73 show short exhaust. The parts manual shows the short exhaust. The Trophy Bible gives the engine #s as KH16597 to GH 34399. My bike is yelow tanked KH169XX so was very early on in the run, but it has the long exhaust. However, I suspect that like you say, they just assembled the bikes with whatever bits they had.
Does anyone know why the exhaust was lengthened?


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Originally Posted by Steve Erickson
Interesting... though the pictured example does not have one fitted.


That's my other TR5T in the picture and I ended up finding a NOS Krizman spark arrestor for US$18.

My 2211 mile TR5T did not have that Krizman decal and neither does a NOS 1974 muffler I have.

Oddly the 1974 bike in the picture was very original and the patina followed through to the '1973 short outlet muffler and even though the two HJ bikes are 100 apart (engine number) even the kick start levers were not the same (dog leg on that one, straight on the other which some regard as 1974)
I guess on that bike they did not remove the decal.... I will take a look later if the 2211 mile bike has remnants of the decal.

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Originally Posted by AngloBike
There are a lot more tr5t's than tr7T's


I thought that once, a TR7T would go nicely (and be more usable) with my TR5T's... I stopped looking and then one day what pops up on eBay locally, an original 1982 TR7T that had been in dry storage for decades and sold for $12000 ( £6000) (US$7000?
You can't have them all and doubt another one will come up for sale

As far as the speedometer, I have never seen anything close to it but it seems odd that the TR5T got oddball instruments as a one model only or as a special order. (Not on some Japanese bike of the period)



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Just been spending some time looking at the parts list for the 1973 TR5T (99-0973) and for the 1974 TR5T (99-2253).
Incidentally for Phils benefit there are no "UK and General Export" market parts lists for the TR5T---at least there aren't any on Kims CD.
The muffler in the 1973 parts list is 71-3062---which interestingly is the number on Les's 74 model pictured earlier in this thread.
The muffler in the 1974 parts list is 71-3793.
Very interestingly the diagrams in the two parts list show a markedly longer tail pipe in the 1974 parts list compared with the 1973 parts list.
As I guess we all know the normal quick differentiator is that the 1973 model has a yellow gas tank and the 1974 modek has a red gas tank.
Another interesting point is that both 1973 and 1974 parts lists show the exhaust pipes with tabs and springs between the exhaust pipe tabs and the engine.
Now I have those springs on my 1974 model (TR5T HJ 566**) but on my 1973 model (TR5T PH 206**) there are no springs and no tabs on the exhausts.
Both of my TR5Ts (1973 and 1974) have the mufflers with the short tail pipe.
It seems vey difficult to put definitive logic to these situations.
Certainly at that time the situation in the factory was chaotic-- the guys there didn't know whether they were going to have a job next week or not so "anything went"--I speak from first hand knowledge as I was there for some of it.
Alongside this we have also to recognize that these bikes are now 46/47 years old.
Who really knows what has happened to individual bikes over this time?
I bought both of mine in 2012 and pretty much know the history of my 1973 and am pretty sure that it is 99% original.
But the 1974 model history is largely unknown --so God knows what might have happened to it before I bought it.
And these bikes are off as well as on road bikes so damage is probably more likely with them than on a road bike.
And mufflers are one of the parts most prone to damage and replacement due to heat, vibration and physical damage.
Perhaps we will never know the answers to some of these questions.
Interesting trying to find out though, isn't it?

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Neither of my 1974's have spring tabs (including a NOS system)

From what I read the short muffler was associated with 1973, the long muffler 1974... I know the history of my low mile 74 because it was on the same Oregon farm from 1974 to 2012 (hence the low miles) (It still had its original Dunlops until then also)

The other 74 (in the picture up the page) had around 4900 miles on the clock and came to Australia from the USA in 2009......... Oddly enough, when I bought my Mk2a Commando out of the USA, the name on its US title was the same as that on the TR5T US title.

Differences that I know of are.
Mufflers.
Head steadies.
Air boxes.
Header tabs (but have not seen them in person)
Kick start levers.
Does the 73 have a gearbox oil dipstick like the 74 ?
Jones or Dunlop rims (Including both on the same bike)

Considering the state of the factory in 1974 they seem to have built a lot of bikes in July (HJ) of that year or did they ?
929 1974 bikes built when or where ?

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In the very late 1960s they were making 50-60, 000 bikes per annum at Meriden.
That is an average of well over 1,000 bikes per week.
I don't think they were capable of assembling that many by 1974 but if they had the parts and bearing in mind that the assemblers were on piece work then they could certainly assemble quite a few bikes.

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I bought a DomiRacer Nippon Seiki speedo (black cup) which is pretty well a match for the TR5t and will serve as a donor for a busted speedo bezel and glass.

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There are now two TR7Ts for sale in Aus, both 19000$A One has been for sale for around three years and the other came on the market in the last few months. I rode one in the weeks after they were introduced here, only briefly, but enough to make me wonder if the 650 might have been a better option. I have awheel for one somewhere. I had visions of fitting it to the TR5t.
Two NOS long version spark arrestors sold on Ebay in the US today at $199US the pair, being suitable for the TR5T. I reckon they must have been for the B50MX, or maybe not a brit bike at all! My parts books show the spark arrestor as a short version on both the 73 (short pipe) and 74 ( lengthed pipe) versions (is that even proper English)
According to the Triumph trophy bible they were built (apart from the first three) 7 Sept 72 to 1 jJune 1973, (73 models) 5 Jul 73 to 20 Jul 73 (74 models). Pretty much a continual run, if not continuous if you consider the British summer (what!!) holiday time.
Time for a nap

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Both 1973 and 1974 TR5Ts take the same spark arrestor---the Krizman KS500.
I thought the ones on E Bay were that type?
The "proper" English is lengthened.
The Coventry Holiday Fortnight in those days were the first two weeks of August.
All the factories in the city closed and the millwrights changed the tooling for the next years models.

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there is a bsa service bulletin showing how to correctly fit
the spark arrestor on b50mx
There must be space left between the spark arrestor and the interior muffler baffles .
there was no stop , so some amount of attention was needed to fit correctly .

Perhaps the modified tailpipe length for later models , was to make it more idiot-proof ?

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That is an interesting possibility as to the reason for the longer tail pipe on later models.
Quinten---do you have a link to the BSA Service Bulletin?

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https://i219.photobucket.com/albums/cc163/Sussexpellett/BSASS7-73.jpg[Linked Image from i219.photobucket.com]

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Many thanks, Quinten, very interesting!

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Yes, interesting... especially considering the bike had been in production for 7 months before this bulletin was issued. I doubt that my 73 has the 3 1/4" projection called for in this publication, will need to check...

Thank you, Quinten.

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