crude leaded fuel in unleaded bikes ???

**patrick kneale** · #1 4 Dec 2002

Can anyone please tell me weather or not using crude leaded petrol like in India , Iran etc. etc. does any damage to an unleaded bike ?? if so are there carbie or piston mods that can be done ???
thanx heaps

**RichLees** · #2 4 Dec 2002

lead was added to fuel to prevent pinking and valve seat wear. now that valves and their seats are harder wearing, lead is no longer needed. as far as I understand it, using lead will not do harm to an engine, but would completely shag a catalyst. if you check the spark plug, you'll find it is grey-green for leaded rather than greyish for unleaded.
more important than lead/no lead, you need to consider pre-ignition and whether to retard your ignition or to reduce the compression to compensate for low octane. what bike are you riding and what load will you be carrying? not all bikes need any mods - my XR400 handled Algerian 80-odd leaded fuel just fine last year - but you can get retarded ignitors/CDIs for high compression KTMs and BMWs
Rich

**Billy Bunter** · #3 4 Dec 2002

For what its worth, i have been putting Iranian/Pakistani leaded fuel in my KTM Adventure for the last 6 weeks and about 3.5 thousand miles, the bike is completely standard. The plug looks the normal light brown and it runs fine.

**Noise Data** · #4 1 Feb 2003

You can get retarder ignitors for KTM and BMW... Some of the models, like new LC8 or GS1150Adventure have the "switch" already as standard equipment

**Noise Data** · #5 1 Feb 2003

You can get retarder ignitors for KTM and BMW... Some of the models, like new LC8 or the 2003 LC4 Adventure have the "switch" already as standard equipment

**Madrid_CapeTown** · #6 26 Mar 2003

Hi!!!
AFAIK , if a bike has not CAT (easy to see if it has a Lambda probe or not @ the exhaust) ... then it will run BETTER , for longer , with less valve wear , and less detonation on PREMIUM LEADED , especially in those hi-temperature environments.
UNLEADED's only reason to exist is to protect petrol-injected cars' cathalysts , whoose expensive platinum alloy would be "poisoned" - rendering useless- with any lead .
Having said that , and for a "uncatalyzed" engine such as most overlanding motorbikes have ... the safest , cheapest ,etc.. fuel is LEADED !.
-pls note that small airplanes (Cesnass , etc) are essencially same design /techhnology/construction that air-cooled motorbike engines ... and run quite happily with super-leaded petrol

Leaded fuel has another's advantages , such as "self sealing" action in fuel screw fittings (producint that "locking" effect in fuel system related nuts), electric fuel pumps bearing lubrication ,
-let alone the valve seat problem -.

On top of that , -apparently - leaded's exhaust smoke is surprisingly "safer" to breathe that the new "unleaded" octane boster , if it werent for the catalyzer.

Cheeeers.