airHEAD
Pack Dog
OK so I know I ride a really old bike ('82 airhead BMW) so not everybody will be able to relate to this one but I recently made an interesting discovery about our local fuel and was wondering if there are any other dogs out there who have had a similar experience.
The old 2-valve airhead even with its dated combustion chamber design has always worked fine on just about any fuel but I went and fitted a "high" (for an airhead) compression 1000cc kit to my 800. I have had unleaded valve seats fitted and definitely don't run a cat so I figured I could use either fuel. Over the 6000km I have done so far on the motor I have chopped and changer between LRP and unleaded.
The bike was running fine during the light load run-in phase but at some point I started noticing bad pre-ignition every time I opened the throttle at low revs. (I bit frustrating when you tried to build the motor specifically to optimise the low end torque
) I had been fiddling with timing and jetting so I didn't immediately put it together but while running on a tank of unleaded fuel during the CABC 2010 event I realized just how badly it was running. I know I was pusshing it much harder than I usually do > but it was really irritating me as I had to drop a gear to get the revs up or close the throttle off to make it go away.
At the event one of the other dogs (Jupiter) suggested I try LRP. They are both branded as 95 octane so I didnt have much hope but thought it was worth a try. Anyway the next refuel was a tank full of LRP and it completely transformed the bike, now it pulls cleanly from 3000rpm in top gear :biggrin: thanks Jup for the tip :thumleft: Has anyone else had a similar experience?
The old 2-valve airhead even with its dated combustion chamber design has always worked fine on just about any fuel but I went and fitted a "high" (for an airhead) compression 1000cc kit to my 800. I have had unleaded valve seats fitted and definitely don't run a cat so I figured I could use either fuel. Over the 6000km I have done so far on the motor I have chopped and changer between LRP and unleaded.
The bike was running fine during the light load run-in phase but at some point I started noticing bad pre-ignition every time I opened the throttle at low revs. (I bit frustrating when you tried to build the motor specifically to optimise the low end torque
) I had been fiddling with timing and jetting so I didn't immediately put it together but while running on a tank of unleaded fuel during the CABC 2010 event I realized just how badly it was running. I know I was pusshing it much harder than I usually do > but it was really irritating me as I had to drop a gear to get the revs up or close the throttle off to make it go away. At the event one of the other dogs (Jupiter) suggested I try LRP. They are both branded as 95 octane so I didnt have much hope but thought it was worth a try. Anyway the next refuel was a tank full of LRP and it completely transformed the bike, now it pulls cleanly from 3000rpm in top gear :biggrin: thanks Jup for the tip :thumleft: Has anyone else had a similar experience?
