Jump to content


Photo
- - - - -

Bsa C15 Engine. Weak Points.?


  • Please log in to reply
9 replies to this topic

#1 andy m

andy m

    Advanced Member

  • Site Supporter
  • 1,862 posts
  • Location:Hereford/ Cider country.
  • Bike:Various..;- )
  • Club:South Shropshire MCC. Hereford Classic TC

Posted 24 January 2012 - 10:55 PM

I need to partly strip a 1963 Distributor C15 engine to check it over , it will be built as a std 250, as soft as possible . I am not up to speed on these only in gaining info in threads I have seen recently. Are there any weak areas to check, I am hoping to get away with top end strip for now , any thing else to check?/ It will be a long term project, just as long as the motor is sound. It kicks over with good compression, supposedly a runner a few years ago. Thanks in advance :thumbup:
"Be on good terms with all persons. Speak your truth quietly and clearly, and listen to others; even the dull and ignorant. They, too, have their story."


Ads By Google User is online

Ads By Google
  • Ad Bots


Don't want these Ads? Why not help support TC and sign up as a Trials Central Supporter?

#2 charlie prescott

charlie prescott

    Advanced Member

  • Members
  • PipPipPip
  • 1,027 posts
  • Location:banbury oxon
  • Bike:bsa Otter's Etc,

Posted 24 January 2012 - 11:21 PM

Hi Guy's.
Hi Andy.
You need to make shure the oil pump is working OK and check that the timing side main bearing bush is free from play.If you have the head and barrel off, just also check that there is no play, (movment ). in the big end as this could be a plain bearing item. Mainly just check for wear on any components.OK

Regards Charlie

#3 woody

woody

    Advanced Member

  • Site Supporter
  • 3,280 posts
  • Location:Birmingham UK

Posted 24 January 2012 - 11:25 PM

Biggest problem with the older Dizzy is the both the bigend and timing side crank bearing are bushes. They're considered a weak point. Others with more knowledge of why will better explain the reason (as far as I know conrod kits are hard to come by as well)

A worthwhile mod when rebuilding is to upgrade these to needle rollers. Alpha Bearings did mine when I rebuilt it and it never gave any trouble. Obviously you're not going to know the condiion of them without stripping and inspecting though. I thought mine was ok and it let go the Sunday before the Pre65 Scottish. That was a frantic few days in the shed and no mistake, including one 5am finish and one work all through the night. I finally finished it at 2pm on the Thursday, got everything packed up, bike into the van and was in Kinlochleven just in time to sign on before 9pm. Never ever want a repeat of that...

The engines perform well as a trials engine with the standard head and road cam. Road gearbox is fine with the correct primary gearing. Triumph 500 (69mm) or 650 (71mm) pistons can be used to get them out to about 275cc for a little bit more torque, not massively different but worth it if you have to rebore anyway.

#4 big_red_bike

big_red_bike

    Member

  • Members
  • PipPip
  • 55 posts
  • Location:England
  • Bike:Gas Gas
  • Club:Various

Posted 25 January 2012 - 05:33 PM

Hi another thing to look out for on the bsa unit single engines is the kickstart quadrant and gearbox main shaft can snap with heavy use of kickstart.

#5 andy m

andy m

    Advanced Member

  • Site Supporter
  • 1,862 posts
  • Location:Hereford/ Cider country.
  • Bike:Various..;- )
  • Club:South Shropshire MCC. Hereford Classic TC

Posted 26 January 2012 - 09:11 PM

Thanks for the replies. Removed the top end, no nasty surprises, no play in big end and doesn't look like any blow by on the piston so will check the piston/ rings / bore clearances and if all okay should get away with rings ?? Spoke to Alpha re the bearing conversions, it will make sense to do them given the age, it's a 63,same age as me... :thumbup:

Will shelve it for a while now I know it's not shot. There's a Bantam needs finishing first.
"Be on good terms with all persons. Speak your truth quietly and clearly, and listen to others; even the dull and ignorant. They, too, have their story."

#6 totalshell

totalshell

    Advanced Member

  • Members
  • PipPipPip
  • 1,706 posts
  • Location:lancashire (just)
  • Bike:in several boxes....
  • Club:Rossendale Harriers, Clarks Commando's

Posted 30 January 2012 - 08:15 PM

my barnetts a 63 and the same age as me.. ask your question on the yorks classic facebook page one of the regular posters only recently sold his c15 and he'd done most stuff to it while he had it..
We few .. We happy few Yorkshiremen..

let Richard III rest in York..

#7 andy m

andy m

    Advanced Member

  • Site Supporter
  • 1,862 posts
  • Location:Hereford/ Cider country.
  • Bike:Various..;- )
  • Club:South Shropshire MCC. Hereford Classic TC

Posted 16 February 2012 - 07:11 PM

Spoke to someone today who has made some phospher bronze replacement bushes for the c15, the top hat and bearing all p.b. Anyone else seen this??
I was there for another reason and spotted some c15 cases on the side....
"Be on good terms with all persons. Speak your truth quietly and clearly, and listen to others; even the dull and ignorant. They, too, have their story."

#8 biggwil

biggwil

    New Member

  • Members
  • Pip
  • 5 posts
  • Location:isle of man
  • Bike:montesa honda mh 200
  • Club:vintage club iom

Posted 21 February 2012 - 09:30 PM

Have just purchased a c15 and the last owner has told me to use p50 oil . Anyone know where I can purchase it? Have googled but not having luck with just p50 . Maybe someone could help with branding or company or different name for it ? Many thanks

#9 mcman56

mcman56

    Advanced Member

  • Members
  • PipPipPip
  • 491 posts
  • Location:N California
  • Bike:Rev3
  • Club:PITS

Posted 22 February 2012 - 11:39 PM

I have heard that a solid bronze main bearings (plain bearing or bushing) transfers heat better than the OEM bushing. When I tore down my C15, I was surprised by the quality of the OEM bush. It was pretty bad. There was an outer steel housing with an inner bushing. The inner bush was not even a machined ring but had a split in it like it is just rolled in place. The inner bush looked to be plated with copper. I coppied the design in solid bronze. The bike is running but does not have many hours on it so I can't make statements about durability.

#10 90vanman

90vanman

    Member

  • Members
  • PipPip
  • 46 posts
  • Location:brentwood essex
  • Bike:honda tlr 200e
  • Club:Eastern 4stroke assn

Posted 25 February 2012 - 07:10 PM

I need to partly strip a 1963 Distributor C15 engine to check it over , it will be built as a std 250, as soft as possible . I am not up to speed on these only in gaining info in threads I have seen recently. Are there any weak areas to check, I am hoping to get away with top end strip for now , any thing else to check?/ It will be a long term project, just as long as the motor is sound. It kicks over with good compression, supposedly a runner a few years ago. Thanks in advance :thumbup:

Hi, when I was modding my B40 I found that a very usefull book to have about was Rupert Ratio. This is a guide written by a very knowledgable bloke, oddly enough not called Rupert. It's well worth having if you can find one, as it outlines mods to the motor like replacing that bushing with something more durable and getting rid of the "distributor", almost to the point of having a G spec.


Ads By Google User is online

Ads By Google
  • Ad Bots


Don't want these Ads? Why not help support TC and sign up as a Trials Central Supporter?



0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users