TR5MX Avenger restoration

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TR5MX Avenger restoration

Post by YK55 » Tue Jan 31, 2012 8:51 pm

Hi all, Rickard suggested I post about my TR5MX Avenger restoration project so here's a bit to start with.......

I've always liked BSA unit singles, I owned a C15 when I was a kid 40 years ago but what I really, REALLY like are the square-barrelled 441s and 500s :cool: for me they are one of the best looking engines of all time :thumb
My TR5MX motor is currently sat on the kitchen table and I'm quite happy to just sit and stare at it with either a beer or glass of red in my hand :grin:

Last year I decided I wanted a B50T so I started looking in the usuak places and placed a bid or two Ebay, then one day I saw a TR5MX and had to have it! I've always loved Triumphs and I already had a TR5T so the TR5MX would make a nice addition. Anyway, I became the new owner and I brought it home and began collecting parts for the restoration. There were quite a few bits missing, including the front wheel and my plan was to put it on the road as a Triumph version of the B50T. However this soon changed into making it into a single-cylinder TR5T.

Here's a couple pictures in 'as bought' condition.

Image

Image
Last edited by YK55 on Thu Feb 02, 2012 10:44 pm, edited 3 times in total.

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Re: TR5MX restoration

Post by HPbyStan » Tue Jan 31, 2012 9:55 pm

I like it in the "as bought" condition.

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Re: TR5MX restoration

Post by YK55 » Tue Jan 31, 2012 9:59 pm

The TR5MX is basically a badge-engineered BSA B50MX, when BSA went out of business the remaining parts were built up as Triumphs. As far as I know they are identical to the B50MX except the Triumph had a 21" front wheel, a full alternator with Lucas MC2 capacitor ignition and the 2 gallon Triumph-style fuel tank. Triumph also sold a 570cc tuning kit as an optional extra. There is a nice road-test article in the March 1974 issue of 'Cycle' magazine comparing the standard and kitted bike which makes interesting reading.

It's a full matching numbers bike, engine and frame, crankcase halves and inner timing cover are all correct. The engine number gives a build date of July 1973 and this date is also engraved on the oil pump however the crankcases are date-stamped 31. 1. 73.

It's a one owner bike, I have California title from August 1973 and it was re-imported back into the UK in 2011 when I bought it. I assume it's unusual for a competition bike to have a US title? It certainly isn't normal in the UK.

The most obvious error was the front wheel which was from a H*nda, I believe a 250 XL Motorsport. The bike wasn't in running condition and looked like it had been standing for many years.

For about 6 months I didn't do anything other than gather parts and information and then I started the strip-down. The bike had obviously had a hard life during it's latter years and had suffered from a lack of maintenance. It was on + .040" rebore but the crankcases had obviously never been split and the bottom end was in remarkably good condition although I have replaced the big end and the main bearings. In fact I have replaced every bearing and bush on the whole bike, those Torrington layshaft bearings are an absolute PIG to remove! I had a new cylinder liner fitted and bored to standard as I had a New Old Stock std Hepolite piston. I have also fitted new valves and Colsibro guides.

I have replaced the close-ratio gearbox with a standard ratio cluster from a low mileage B50T and I have converted to a 3/8ths drive chain using a 17T gearbox sprocket and 47T rear wheel sprocket from a BSA A65. The engine is now ready to go back in the frame but I need to fit a tachometer drive first. I bought a New Old Stock one but it turned out to be for the earlier B25/B44 models and it won't clear the frame so if you know where I can get the later type I'd be very grateful!
Andy.
Last edited by YK55 on Tue Jan 31, 2012 10:24 pm, edited 1 time in total.

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Re: TR5MX restoration

Post by YK55 » Tue Jan 31, 2012 10:02 pm

HPbyStan wrote:I like it in the "as bought" condition.
It was worse than it looks! It wasn't useable at all as it was, everything needed overhauling.
Andy.

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Re: TR5MX restoration

Post by koncretekid » Tue Jan 31, 2012 10:15 pm

I give up! How did they get a 670cc kit out of the B50? I want one.
Tom

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Re: TR5MX restoration

Post by YK55 » Tue Jan 31, 2012 10:26 pm

koncretekid wrote:I give up! How did they get a 670cc kit out of the B50? I want one.
Tom
Oops! My error, it was 570cc, (I've edited the original post)

There is a copy of Cycle magazine on Ebay at the moment :-

http://www.ebay.co.uk/itm/CYCLE-MARCH-1 ... 45f7f3f98a

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Re: TR5MX Avenger restoration

Post by 2manyrides » Wed Feb 01, 2012 2:43 pm

In the days when there wasn't a whole lot happening down at the triumph shop, (late 70's early 80's), I bought the big bore kit from my local dealer who had it in the bargin bin.
New piston, rings, wrist pin, liner...
Price... $40.00

I could not pass that up!
I never did put it in my TR5MX, but did install it in a B50 motor. I was pleased with the results. It's like the C/W article states. I have that issue of C/W.

But if you talk to Ed at EV he'll tell you this is not the "ideal" method for boosting your umph!

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Re: TR5MX Avenger restoration

Post by b50root » Wed Feb 01, 2012 3:03 pm


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Re: TR5MX Avenger restoration

Post by HPbyStan » Wed Feb 01, 2012 7:08 pm

That sorry a$$ed piston belongs in a tractor not a motorbike.

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Re: TR5MX Avenger restoration

Post by Michael Moore » Thu Mar 29, 2012 5:48 pm

Are the side panels under the seat still available? If not, I can take some photos of mine for you if you need to replicate them.

cheers,
Michael

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Re: TR5MX Avenger restoration

Post by B44R » Fri Mar 30, 2012 10:24 am

This place in the UK does side panels

http://www.cmf-engineering.com/

Chris...

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Re: TR5MX Avenger restoration

Post by YK55 » Mon Apr 02, 2012 6:59 pm

Michael Moore wrote:Are the side panels under the seat still available? If not, I can take some photos of mine for you if you need to replicate them.
cheers,
Michael
Hi Michael, many thanks for your very kind offer, I have a pair of reproduction side panels ready for fitting :thumb
Andy.

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Re: TR5MX Avenger restoration

Post by YK55 » Mon Mar 26, 2018 11:53 pm

Just to update this thread, I sold the TR5MX a couple of years ago to a good friend of mine and it now resides in the in the Transport Museum at Jurby in the Isle of Man. I've re-posted the original pictures thanks to Photobucket playing silly buggers.

As bought.

Image

Image

When finished.

Image

Image
Last edited by YK55 on Wed May 02, 2018 5:14 pm, edited 2 times in total.

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Re: TR5MX Avenger restoration

Post by beat » Tue Mar 27, 2018 7:35 pm

:thumb :thumb

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