B50T US import

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Victor500T
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B50T US import

Post by Victor500T » Sun Apr 30, 2017 12:16 am

I thought it probably about time I started a thread on this bike in the projects section, so here it is. No pics yet as I need to figure out how to load them onto here (I am not at all tech savvy, so even simple things take a great deal of figuring out for me, if I haven't one them before. The thing that's baffling me just now is the requirement to 'shrink' the number of kilobytes to under 500. When I work it out, I'll post lots of pics - I've been taking some from day 1).

Today i got the engine out of the frame, having previously stripped out the gearbox, clutch etc. The genuine BSA manual let me down. It states that the correct method is to remove the aft right hand engine plate and remove the engine from the right hand side. So, that's what I struggled with for 1/2 hour before giving up, removing the left plate and taking the lump out on that side. The only way it's possible as far as I can see. I notice that the drawing in the manual is of a B25 engine. I;m sure it's easy to remove one of them from the right side, but with the extra height of the B50, there's no way.

It also doesn;t tell you that you have to remove the nuts holding the head steady bracket down, but you won't be able to take the bracket off unless you tilt the engine forward by quite a few degrees.

The good news is that all the engine mountings are good - no sign of them ever having been run with loose bolts. And the proper spacers were in place - I'm sure the engine hasn't been removed since it left Birmingham in 1971 or 2. Which brings me to another thing....

I thought my bike was made in September 1971, going by the KG frame & engine number. But it has 1972 parts all over it, eg: the rivetted clutch centre, the large (80mm, normal for T120s etc) speedo, the points wire going through a round grommet above the points, the paint scheme (white along the top of the tank with metallic purple (or Flamburgundy or whatever BSA called it) diagonal bars, and various other 'late' details.

Anyway, all for now. Next job )tomorrow) is to get the head & barrel off, and see what the piston & bore are like.

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Re: B50T US import

Post by Barry Creary » Sun Apr 30, 2017 1:32 am

There's a free app called Iresize and is easy to use <201

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Re: B50T US import

Post by AWJD » Sun Apr 30, 2017 7:18 am

I always get a little confused over this issue but your Sep '71 bike makes it a 1972 model. In other words, you need to look at the 1972 Parts Book rather than the intuitive approach of looking at the 1971 Parts Book!
1971 B25T x 2
1971 B50T
1973 B50MX

Victor500T
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Re: B50T US import

Post by Victor500T » Sun Apr 30, 2017 11:36 am

Barry Creary wrote:There's a free app called Iresize and is easy to use <201

I don't actually know what an 'app' is - aren't these for mobile phones? I don;t have one of those, just this laptop!

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Re: B50T US import

Post by AWJD » Sun Apr 30, 2017 1:26 pm

You can download it for Windows from:

https://iresize.en.softonic.com/
1971 B25T x 2
1971 B50T
1973 B50MX

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Re: B50T US import

Post by Victor500T » Sun Apr 30, 2017 9:35 pm

AWJD wrote:You can download it for Windows from:

https://iresize.en.softonic.com/

Thanks AWJD - I hope to pluck up the courage to click the link maybe tomorrow. Certainly not now - a stressful enough day as it has been! My problem is that I KNOW something's going to go horribly wrong and require me asking someone who knows about such things, like my brother, to come over and sort it out for me, that I daren't even attempt anything I have no clue about....

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Re: B50T US import

Post by Victor500T » Tue May 02, 2017 10:22 am

I must learn how to post pics on here. The iresize thing looks good, I'll try it this evening if I have time. But once I've re-sized myphoto, can I make it appear on here without resorting to Photobucket?

I dismantled the engine yesterday. The piston looks very good - no trace of scuffing or heat seizing, or detonation damage, and the rings look as if they will be free-able from their grooves with a little more patience. The bore has discoloured patches caused by rust, but after wiping it clean with rags, I can barely feel anything even on the worst areas with fingertips. There is no sign of wear at all. So, I'm hoping I can find a set of std Hepolite rings, and just get the barrel honed.

The base gasket came away stuck to the cylinder base, in perfect condition, so unless it gets damages during cleaning / honing, I'll re-use it.

The conrod is mirror polished and the flywheels look like new. I'm not used to things going this well!

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Re: B50T US import

Post by midgie » Tue May 02, 2017 3:50 pm

that's a lot of work involved when it starts leaking, for the sake of a new base gasket. go on give the cat a goldfish!

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Re: B50T US import

Post by Victor500T » Tue May 02, 2017 4:39 pm

I thought things were going too well. Not that anything bad has happened, but I had been assuming that the piston would be std, because the engine looks so untouched (the original Phillips head casing screws, all the rockerbox & head nuts & washers etc, looked undisturbed or at least, disturbed with all proper care, unlike the superficial bodges to the wiring, exhaust, mudguards etc that the bike came with).

But on measuring it, it turns out to be +.040". And I've got the oil control ring free, and the 2nd comp ring starting to budge, but the top one still refuses to move.

The piston has hardly done any miles by the look of the interior of the crown, and there wasn't much carbon on the top (nor on valves or combustion chamber).

There is something odd (seeming) about the piston's part number - I;ll post this in the tech section as well. It is 71-2751, which is very different to the numbers in my parts book.

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Re: B50T US import

Post by midgie » Tue May 02, 2017 6:57 pm

71-2751 is indeed a hepolite +040" piston and bsa didn't list anything over this size. but you can go up to 88mm which gives approx. 545cc still using the standard liner.i would recommend the usa made JE brand pistons. not to be confused with the Australian jp brand which are poor to be polite!

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Re: B50T US import

Post by beat » Tue May 02, 2017 7:17 pm

I go with midgie.
if you have to get a new piston, go for a JB, then you can use the bike.
Hepolite is good if the vehicle remains in the garage for ever .....

beat <212

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Re: B50T US import

Post by Victor500T » Tue May 02, 2017 9:25 pm

Now I'm getting confused! Is it JP, JE or JB that are the good ones? I guess it's US made JE (I have come across bad reports on Ozzie JP pistons, but I don;t know that I've come across the JB brand before?). The problem with JE is their American-ness. Meaning, they'll have to be imported unless anyone here retails them. Which mean postage plus UK import tax plus UK post office handling charge, which all adds up to a hell of a lot, and I am not a wealthy man!

I don't get the objection to Hepolite. I'm not talking about the current "Hepolite" brand which is actually just Wassell (a company justifiably shunned where all engine components are concerned). I;m talking about an original Hepolite. There was nowt wrong with them (was there?).

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Re: B50T US import

Post by midgie » Tue May 02, 2017 9:42 pm

nothing wrong with genuine hepolite pistons, I don't know about the new hepolite brand, but if wassells have anything to do with it, I think we know the answer there judging by the rest of their pattern parts!

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Re: B50T US import

Post by beat » Wed May 03, 2017 9:34 pm

Victor500T wrote: I;m talking about an original Hepolite.
DSCN8317.jpg
Hepolite - original ore not ??
DSCN9304.jpg
Holes and Cracks right through the skirt !!
hepolite ore gpm ore what ever: - it was cheap and I was warned....
surprisingly the crown did not fall off whilst running.....
beat <022

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Re: B50T US import

Post by Victor500T » Wed May 03, 2017 10:23 pm

My piston looks like the one on the right of your pic, Beat. I haven't seen the type with the three grooves around the skirt before. That one you show the close-up of looks terrible - air bubbles in the casting? If that was an original piston, I think you must have been unlucky. Normally, Hepolite pistons were very good, and fitted as standard to almost all British bikes until they stopped being made, as far as I know.

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Re: B50T US import

Post by Victor500T » Wed May 03, 2017 11:05 pm

Here (I hope) are some pics of my B50 project. The pics are in chronological order, from the day it was delivered up to a few days ago when I got the barrel off. No captions yet - I'll try to add some when I know this has worked...

Image

Image

Image

Image

Image

Image

Image

Image

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Re: B50T US import

Post by lathejack » Thu May 04, 2017 9:15 am

Ah, I remember watching this one on eBay, it was for sale in Stoke on Trent wasn't it?
It certainly looks to be in mostly very good condition, as a lot of these coming home from the USA are.

I would think the front tyre is hardly worn, having probably spent most of its time airborne with a rear sprocket the size of that one.

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Re: B50T US import

Post by Victor500T » Thu May 04, 2017 1:05 pm

lathejack wrote:Ah, I remember watching this one on eBay, it was for sale in Stoke on Trent wasn't it?
It certainly looks to be in mostly very good condition, as a lot of these coming home from the USA are.

I would think the front tyre is hardly worn, having probably spent most of its time airborne with a rear sprocket the size of that one.
Yes, that's the one. It was advertised as seized but it had a lot of very clear photos, which made it possible to guess that the overall condition might well be pretty good, as it has turned out to be.

It's a hard bike to 'read', this one. It has definite signs of having been in the hands of someone with some very odd ideas (eg: the 35mph top speed sprockets, the amazing air filter, the way the front indicators have been hacksawed off and the incredible bodgery of the wiring). But it also looks as if the only people ever to have undertaken anything at all serious knew their stuff and caused no damage. I was very surprised to find that it had been bored to +.040". Everything else about the engine, and the frame, forks & wheels, made me think that the mileage (1880) was probably true. But two rebores must surely mean at least 20,000 miles, even running without an air filter in the dust?

The tyres look original (though they may not be - I'm sure Dunlop Trials Universals were all anyone used in the '70s). The wheels are straight, no dents or scratches or other witness marks of tyre changing or banging into rocks. The only damage to the frame is the two tabs through which the seat studs go are cracked, but this is very common and not surprising to find even on a low mileage bike.

Usually, bikes that have had much off road use have plenty of dents and weld repairs to show for it. So I'm still a bit puzzled by the +.040" piston.

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Re: B50T US import

Post by skippy » Thu May 04, 2017 11:26 pm

Victor500T wrote:So I'm still a bit puzzled by the +.040" piston.
This may have been what they had or a bit more performance.
Doug
Should never have sold them old motorbikes

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Re: B50T US import

Post by Victor500T » Thu May 04, 2017 11:52 pm

Yes, that's a possible explanation Skippy. Another possible one I've thought of is that it was done under warranty, after a gudgeon pin circlip failure caused scoring more than 10 thou deep? I don;t suppose I'll ver know, but I do think it is something of an anomaly.

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Re: B50T US import

Post by Sly Dixon » Fri May 05, 2017 4:07 am

JP Pistons are ok but their rings are shocking. I ended up with a Hap Jones piston in mine which seems to work well but I'd be equally happy with the JP if I had a decent set of rings to go with it. If it was me I'd be tempted to clean up what you've got and stick it back together with a set of new rings and see how it goes. You can't do another rebore on it as it's already at max but if your clearances are ok and the bore polishes up ok you'll probably be fine. I'd definitely want to change that trials gearing though.

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Re: B50T US import

Post by Victor500T » Fri May 05, 2017 10:39 am

Yes, cleaning up the existing piston & bore and fitting new rings is the plan, but it depends on whether I can get the top ring unstuck. It is proving very stubborn. It's been soaking (again) in 50/50 ATF/acetone overnight, so I'll drain it and try some more heat (again). If that doesn't work, I might get a whole new piston (a member has kindly offered one at a very fair price).

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Re: B50T US import

Post by beat » Fri May 05, 2017 9:10 pm

Victor500T wrote: I haven't seen the type with the three grooves around the skirt before.
:lol: :lol: the three grooves are made by myself , they are there to avoid sizing the the skirt when engine is runned very " hot ".
and, IMO they do the job.
but nowadays, I have mod. the oilery, - no more signs for sizing.
Victor500T wrote:air bubbles in the casting? If that was an original piston,
yes, air bobbles in the cast, and it was a brand new piston, I guess it was gpm. - and I was not unlucky, no, I was really lucky to have NO seriously problems with!
- and it has done a lot of miles two. <212 <212

beat :mrgreen: :mrgreen:

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