Unleaded gas in BSA?
Robert Quinlan
Thunderbolt (1972). Here in Canada leaded gas is gone. Will I have to use
a lead substitute? Which one is good?
Thanks for any info
Robert
Allan Johnson
>Robert Quinlan (rqui...@Direct.CA) wrote:
>: Does anyone know if it is ok (or not) to use unleaded gas in an older BSA
>: Thunderbolt (1972). Here in Canada leaded gas is gone. Will I have to use
>: a lead substitute? Which one is good?
>I would seriously look into a lead substitute. The lead in old 'regular'
>fuel formed deposits on your valves that cushioned the hammering that a
>returning valve can produce. Without the returning valves can quickly
>wear out the valve seats.
>Now, I don't know much about BSA bikes and they may have a hardened valve
>seats. If this is the case, ignore the paragraph above.
>Geoff
Canadian gasoline still has MMT (organic manganese) as a replacement for
the TEL (tetra-ethyl lead) so as long as as the fuel has a high enough
octane rating for the compression ratio you are using, you should be OK.
Really it is only the 60's and 70's autos with valve rotators and "crash"
valve seating (valve and seat ground 1/2 degree different to each other)
which need the lubrication of the lead, and valve rotators were originally
put on these vehicles to scrub off lead deposits from valve and valve
seats. As long as you have the regular parallel valve/seat grind, most
alloy-headed British motorcycles have hard enough seats and valves to go the
25,000 or so miles they were designed to go before a top end job.
Allan Johnson
joh...@env.gov.on.ca
Geoff Hamer
: Does anyone know if it is ok (or not) to use unleaded gas in an older BSA
: Thunderbolt (1972). Here in Canada leaded gas is gone. Will I have to use
: a lead substitute? Which one is good?
I would seriously look into a lead substitute. The lead in old 'regular'
fuel formed deposits on your valves that cushioned the hammering that a
returning valve can produce. Without the returning valves can quickly
wear out the valve seats.
Now, I don't know much about BSA bikes and they may have a hardened valve
seats. If this is the case, ignore the paragraph above.
Geoff
--
.oooO / ) ( \ Oooo. Mr. Geoff "I'm between bikes OK!!" Hamer DoD#1492
( ) / ( ) \ ( ) Past Virago owner.... Future V-Max owner
\ ( ( ) ( ) ) / Visit Canada, see our fjords, ride on our Icephalt
--\_).oooO-Oooo.(_/--- gha...@ingenia.com. Ottawa, Canada
Mark Brauer
>Robert Quinlan (rqui...@Direct.CA) wrote:
>: Does anyone know if it is ok (or not) to use unleaded gas in an older BSA
>: Thunderbolt (1972). Here in Canada leaded gas is gone.
These bikes have hardened valve seats and don't require the lead to lubricate the valves and seats. I have run aluminum headed Brit=
-bikes for years on unleaded gas with no ill effects. I DO stick to the highest octane I can find, though.
Mark Brauer 1975 Triumph Trident T-160
Espen Olsen
>Does anyone know if it is ok (or not) to use unleaded gas in an older BSA
>Thunderbolt (1972). Here in Canada leaded gas is gone. Will I have to use
>a lead substitute? Which one is good?
>Thanks for any info
On older bikes with aluminium heads, it's OK to use unleaded provided the
octane rating is high enough. Aluminium heads will have hardened valve seats
inserted unlike most older iron heads.
Espen
LA6MGA/LA1K, DoD# 7962
Det er når en kjenner lukten av sin egen avføring at man lurer på
hvem man egentlig er.
A.And