1972 B50T from Frankenbike back to near stock.

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1972 B50T from Frankenbike back to near stock.

Post by Winsur44 » Sun Mar 12, 2017 9:33 pm

I have finally quit my traveling sales job, so I now have time to disassemble my 1972 B50T for restoration. Somehow this bike went from being my acquaintance Tim's "Favorite Ride," maintained by a local expert mechanic, to being an albatross around my neck. Oh well, I need a challenge to stave off dementia for another few months. Though I have maintained and rebuilt may bikes, this will be my toughest attempt so far.

My plan was to put the B50T back to stock as much as possible cosmetically, and to do the upgrades that are recommended on the site. I have a lot of experience with engines, but very little with transmissions. My last transmission rebuild was a Triumph 500 in 1968. I had the assistance of Jack Wilson of Big D Cycle, who sold me the manual, parts and gave me phone support. It does not get any better than that.

B50T as purchased:
Tims B50.jpg
Tim's B50T
At the time of purchase, it had some obvious problems:
1. Muffler from a Harley (Sacrilege)
2. Cheapest aftermarket headlight available for purchase
3. Front fender mounted backwards.
4. No compression release.
5. No speedometer, or drive gear for the speedometer.

It also had, as I was to find out, a few not-so-obvious problems.
1. Stock push rods with matched with a .050 cylinder space. This made the valves unable to be set properly.
2. Stock wiring that had many holes in the insulation.
3. The rear wheel was laced to far to the right, so that the stock muffler cannot be mounted without hitting the rear wheel.
4. No top engine mount

Thanks to Rabers in San Jose CA, I now have a top mount and the proper pushrods that match up to the Cylinder spacer that came with the B50. I have pulled the engine and mounted it on the bench engine stand I purchased years ago on EBay. I have also accumulated an unbelievable amount of parts by purchasing a huge parts lot, and 2 more B50s
B50 Engine stand.JPG
Engine Stand
Problem #1: Aluminum flakes in the transmission.
One of my first posts was in Jan 2008. viewtopic.php?t=1614
I parked the B50 in August 2013. I'm still not sure what to do with it. The motor ran well when parked. I did not to my satisfaction flush out the transmission of the Aluminum flakes caused when the kickstart ratchet nut came loose and ground into the sidecover. (See above link). I am not all that enthusiastic about completely disassembling the engine - transmission to clean up the slag, but the idea of aluminum circulating around in the transmission is not comforting either. Originally I put auto transmission fluid in, drove it around the block and drained it and looked for flakes of Aluminum. After about 5 time, I was still seeing the flakes. My next thought, now that the engine is removed, is to pump varsol through the transmission. I can do this pretty easily. Any thoughts?

Problem #2: One of the valve cover studs is stripped.
I have thought of doing the stud pull procedure described on the site. This would also allow me to mate the surfaces to incurr less chance of an oil leak. For my metric motorcycles, I have the Time Sert for 8x125 conversion, and I could use the correct length metric socket head screws. I prefer Time Sert to helicoil kits. I could also just buy the TS for the 5/16 and put the stock stud back on, or try one of the LOCTITE 28654 Stripped Thread Repair Kit, 12.9mL, Gray. I am amazed on how hard it seems to be to keep the the valve cover from leaking. With the spacer under the cylinder, will I be able to still remove the valve cover in the frame? Or do I have to at least tilt the engine anyway to pull the valve cover, so it does not matter about the extra .050 of height? Reading some of the posts, I was not sure. How hard is it to remove the valve cover studs? They look pretty tight to me. I have a stud puller. Was Loctite red used to from the factory? I have an 8mm stud puller from Hazet, that I believe will work. The puller pretty much does in the threads on the stud.
Hazet.JPG
hazet
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72 BSA B50SS B50 Cafe
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Re: 1972 B50T from Frankenbike back to near stock.

Post by minetymenace » Sun Mar 12, 2017 9:43 pm

The studs are not (or should not be) bottomed out, but may be loc-tited in. Two nuts locked together on the upper threads, a bit of heat to soften any goo, and the should come out without much trouble.....
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Re: 1972 B50T from Frankenbike back to near stock.

Post by midgie » Sun Mar 12, 2017 9:43 pm

you need to put on plenty of heat to break that red Loctite the factory applied on assembly, or you can strip the threads.

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Re: 1972 B50T from Frankenbike back to near stock.

Post by Winsur44 » Mon Mar 13, 2017 4:27 am

Taking it completely apart. How did it get so oily with only 300 miles since the last cleaning. I forgot to mention that the ribbed 20 inch front tire needs to be updated. Hard to believe it was being used as a dirt bike.
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B50 50T disassembled.jpg
Taking apart my B50T
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USNOA 2062
75 Commando
74 R90R/6
74 R90S
72 Ducati 250
72 BSA B50SS B50 Cafe
72 BSA B50T
08 V*trom 1000
67 Hond* S90
74 Triumph TR50MX
Piles of 250 parts and rolling chassis.
06 S*zuki DRZ 400
73 Triumph 500 T5TR

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Re: 1972 B50T from Frankenbike back to near stock.

Post by mlb50 » Sun Mar 19, 2017 1:16 am

For the rocker box, on a B50 you cannot remove it when in the frame as the studs heights prevent it. The practical solution is to fit 8mm Timeserts or Helicoils as you wish, and use Allen screws to fasten it down. Note, on the timing side, its better to use hex bolts as its difficult to get the Allen key under the top frame tube, a spanner fits easier.Recommend that you get Ed V's metal rubber rocker gasket, get a couple just as a spare.

Tip for removing the old studs - fit 2 nuts onto the stud, tighten against each other with 2 spanners and use 1 spanner on the lower nut to wind out the stud. Put the stud into the bench vise and undo the nuts. Repeat for all studs.

As an anecdote for the benefit of using bolts instead of studs, I was timing the motor (in the bike) and accidentally inverted the TDC tool and the plunger fell into the cylinder via the spark plug hole. I had the head off in 35 minutes, retrieved the plunger and all back and running in 60 minutes. The awful standard no option would be to pull the motor out of the frame!

The gearbox is no great surprise, you can pretty much strip all of it in the frame, and without touching the primary side - just from the timing side only, everything but the high gear cog. That allows you to completely clean the box and check 7 out of 8 gears.
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Re: 1972 B50T from Frankenbike back to near stock.

Post by Winsur44 » Tue Mar 21, 2017 4:34 am

The studs came out easily. I guess they were pulled before. My Hazel stud puller tool was barely needed but made the pulling them easy. I have a Britgasket kit I bought several years ago, having used only the 2 side cover and inspection cover gaskets. I bought the set after seeing a post here. I have pulled the primary cover and the casket looks good. I must have used silocone on both sides of the inspection cover gasket, it came apart when pulled, so I will need a new one. I am ready to pull the head.
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USNOA 2062
75 Commando
74 R90R/6
74 R90S
72 Ducati 250
72 BSA B50SS B50 Cafe
72 BSA B50T
08 V*trom 1000
67 Hond* S90
74 Triumph TR50MX
Piles of 250 parts and rolling chassis.
06 S*zuki DRZ 400
73 Triumph 500 T5TR

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Re: 1972 B50T from Frankenbike back to near stock.

Post by Winsur44 » Tue Mar 21, 2017 4:46 am

Something I didn't mention was the replacement of the 20" tire. I am not seeing any tire selections. Should I be looking to replace with a 21"? Any recommendation on who in the US to choose to relace the rim? Are there any sources for 20" universal tread tires? The ribbed front tire is old and looks ridiculous. What is the story on the 20" tire? I have never seen one except on the B50, and I have owned a lot of bikes in my 55 yeas of driving.
Association does not prove the cause
USNOA 2062
75 Commando
74 R90R/6
74 R90S
72 Ducati 250
72 BSA B50SS B50 Cafe
72 BSA B50T
08 V*trom 1000
67 Hond* S90
74 Triumph TR50MX
Piles of 250 parts and rolling chassis.
06 S*zuki DRZ 400
73 Triumph 500 T5TR

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