1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Project The Mistress. BSA B31 350cc

Discussion in 'Other Projects - Other Bikes (non 250's)' started by Evo, Apr 9, 2017.

  1. Evo

    Evo Well-Known Member

    Messages:
    117
    Likes Received:
    95
    Trophy Points:
    228
    Joined:
    Feb 17, 2015
    Gender:
    Male
    Location:
    Adelaide
    My Bike:
    GSX250
    IMG_1561.JPG IMG_1608.JPG IMG_1625.JPG IMG_1755.PNG I have a new mistress in my life. A 1950 BSA B31

    Saw this on gumtree late November last year and knew I had to have it. So after waiting for it to be trucked over to Adelaide and arriving 2 days after I left on a 6week overseas trip ( i swear I thought about this bike everyday we were away) I finally saw it for the first time late January.

    It was a big risk buying an unseen bike but was more than happy with it and had been given a very realistic discription by the seller.

    Long story short I did the following.
    Gearbox oil
    Clean out oil tank, new oil (3 changes)
    Primary drive case gasket and oil
    Clean the chain and oil
    Cleaned the carby. New seals and gaskets
    New battery
    Checked brakes
    New fork boots
    New spark plug
    Fresh fuel

    After about 5 kicks she came to life. So much relief.

    Got rego for it the other day and took it out for its first (legal) ride yesterday with a massive smile on my face. Can't wait to take it out again

    I realise this is not the typical bike on here but I'll think I'll hang around as there is such a wealth of friendly knowledge around here.
     
    • Like Like x 4
    • Winner Winner x 3
  2. kiffsta

    kiffsta Senior Member

    Messages:
    9,066
    Likes Received:
    6,872
    Trophy Points:
    1,168
    Joined:
    Aug 7, 2010
    Gender:
    Male
    Location:
    Brisbane
    That's awesome , congrats on buying such a cool bike
     
  3. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

    Messages:
    10,914
    Likes Received:
    6,708
    Trophy Points:
    1,168
    Joined:
    Jun 14, 2012
    Gender:
    Male
    Occupation:
    Between a Rock and a Hard Place
    Location:
    North by NW NSW Oztralia - Tamworth
    My Bike:
    *Kawasaki ZXR250C *Yamaha FZR250R 3LN1 *Yamaha FZR400 *Triumph Bonneville 750 T140V *Triumph Daytona 675 *Triumph Tiger 800XC
    Brilliant mate .... always great to see old school and not made in Japan :D
     
  4. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

    Messages:
    6,397
    Likes Received:
    4,785
    Trophy Points:
    1,148
    Joined:
    May 4, 2013
    Gender:
    Male
    Occupation:
    Retired
    Location:
    Tamworth, NSW
    My Bike:
    1937 Royal Enfield 250, CF Moto 250 V5, Honda's XL250, CBR250, FT500 plus a few others.
    Nice.
     
  5. risky

    risky risky

    Messages:
    4,555
    Likes Received:
    1,177
    Trophy Points:
    923
    Joined:
    Nov 4, 2012
    Gender:
    Male
    Occupation:
    risky by name AND actions
    Location:
    newcastle,australia
    My Bike:
    honda ca77, megelli x2,fzr yamaha x 5 ,maxim,cb750.cb600 hornet,zxr250,marusho magnum electra.
    very nice
     
  6. Brizfox

    Brizfox Well-Known Member Premium Member Contributing Member

    Messages:
    335
    Likes Received:
    337
    Trophy Points:
    273
    Joined:
    Jul 22, 2013
    Gender:
    Male
    Occupation:
    Sparky
    Location:
    Brisbane
    My Bike:
    NSR 250 R + CBR250RR race bike,and finally 2x NS 400 R
    Jesus that looks good.
     
  7. Wozza

    Wozza Active Member

    Messages:
    361
    Likes Received:
    191
    Trophy Points:
    148
    Joined:
    Mar 21, 2017
    Gender:
    Male
    Location:
    South Australia
    My Bike:
    GB250
    Oh My that brings back some memory's :) nice bike use to love mine but had to sell her back in the early 90's :( As I could only bring one bike when I moved to S.A img040.jpg
     
    • Like Like x 2
    • Agree Agree x 1
  8. Evo

    Evo Well-Known Member

    Messages:
    117
    Likes Received:
    95
    Trophy Points:
    228
    Joined:
    Feb 17, 2015
    Gender:
    Male
    Location:
    Adelaide
    My Bike:
    GSX250
    So started to pull the engine apart for a general checkover and to remove the Magneto as it needs a referb. The more I pulled apart the more I discovered. Drilled out timing gears, ground rockers and then discovered it has been bored out to fit a Triumph T140 piston to make it a (roughly) 400cc. This would also explained the larger than stock carb its running.

    Someone has done some work to this engine in the past

    IMG_2134.JPG IMG_2135.JPG IMG_2139.JPG IMG_2140.JPG
     
    • Winner Winner x 3
    • Like Like x 1
  9. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

    Messages:
    4,313
    Likes Received:
    2,383
    Trophy Points:
    898
    Joined:
    Jun 18, 2016
    Gender:
    Male
    Occupation:
    Panel Beater, Spray Painter, Custom Fabricator
    Location:
    Adelaide, South Australia
    My Bike:
    Yamaha's , 1990 FZR250R 3LN3 , 1986 XT250TS 57R , 1984 IT200L 43G, 1976 IT400C 510
    Nice, cant complain about that.
    Look's like the head has had some port work done as well, or at least the intake has, i reckon the short return's would have been cleaned up too
     
  10. Evo

    Evo Well-Known Member

    Messages:
    117
    Likes Received:
    95
    Trophy Points:
    228
    Joined:
    Feb 17, 2015
    Gender:
    Male
    Location:
    Adelaide
    My Bike:
    GSX250
    Yea, the intake has been done but it needs a good clean up to see exactly what has been done
     
    • Like Like x 1
  11. gregt

    gregt Well-Known Member Premium Member

    Messages:
    320
    Likes Received:
    292
    Trophy Points:
    273
    Joined:
    Mar 26, 2016
    Gender:
    Male
    Location:
    Hororata NZ
    My Bike:
    many and varied
    There used to be quite a few iron BSA singles active in Classic racing here. The recipe as you have it was quite common. They go quite well too.
    The big question is - what numbers are on the cams ?
     
  12. Evo

    Evo Well-Known Member

    Messages:
    117
    Likes Received:
    95
    Trophy Points:
    228
    Joined:
    Feb 17, 2015
    Gender:
    Male
    Location:
    Adelaide
    My Bike:
    GSX250
    Yep that's the next thing to look at. Hoping the bloke who did this didn't do all of this without replacing the cams with goldie ones or the like
     
  13. tarmacsurfer

    tarmacsurfer Well-Known Member

    Messages:
    152
    Likes Received:
    88
    Trophy Points:
    228
    Joined:
    Jun 27, 2014
    Gender:
    Male
    Location:
    UK
    I like that a lot!
     
  14. Evo

    Evo Well-Known Member

    Messages:
    117
    Likes Received:
    95
    Trophy Points:
    228
    Joined:
    Feb 17, 2015
    Gender:
    Male
    Location:
    Adelaide
    My Bike:
    GSX250
    IMG_2738.JPG IMG_2739.JPG IMG_2740.JPG So long story short I put in new rings and she is running sweet (for now, let's hope it continues) also a new set of tyres. Took it out this arvo for a bit of a shake down.
    Did the obligatory Jetty road then espy cruised it back to Brighton (the Adelaide guys will know) all went well till i felt the battery holder hit my leg. Pulled over put a cable tie in did a U turn and fount the bolt in the middle of the road. Not bad at all considering.
    Had a massive smile on my face the whole way
     
    • Like Like x 5
    • Winner Winner x 1
    Last edited: Sep 19, 2017
  15. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

    Messages:
    4,313
    Likes Received:
    2,383
    Trophy Points:
    898
    Joined:
    Jun 18, 2016
    Gender:
    Male
    Occupation:
    Panel Beater, Spray Painter, Custom Fabricator
    Location:
    Adelaide, South Australia
    My Bike:
    Yamaha's , 1990 FZR250R 3LN3 , 1986 XT250TS 57R , 1984 IT200L 43G, 1976 IT400C 510
    Nice work!
    And a top day for it too.
    You're only just down the road from me, i'm at South Brighton
     
  16. Evo

    Evo Well-Known Member

    Messages:
    117
    Likes Received:
    95
    Trophy Points:
    228
    Joined:
    Feb 17, 2015
    Gender:
    Male
    Location:
    Adelaide
    My Bike:
    GSX250
    I'm also at south brighton. Small world

     
    • Agree Agree x 1
  17. Mike Fulcher

    Mike Fulcher Active Member

    Messages:
    118
    Likes Received:
    38
    Trophy Points:
    53
    Joined:
    Feb 3, 2018
    Gender:
    Male
    Occupation:
    Owner of Mikes Chainsaws & Outdoor Power Ltd
    Location:
    New Plymouth New Zealand
    My Bike:
    85' Yamaha SRX 250, 87' Honda VT250, 86' Suzuki NZ 250, 87' Honda CBX 250, 74' Yamaha AGR100R Racer
    An awesome old classic, these bikes can be modified very successfully for the modern classic racing scene.
    One advantage with the older cast iron cylinder heads is there is almost no restriction on how open you can enlarge the intake & exhaust ports. with modern camshaft theories its not that difficult to design your own what call scatter profile patterns, and machining up cams is not that expensive these days.
    Come on guys, whats your thoughts?
     

Share This Page