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Chris_T
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Lancashire, UK
Joined: 01/27/2016
Posts: 5

Does anyone use fuel additives in their bikes when using unleaded?

Having read a lot on forums quite a few people seem to just use unleaded with no additives which seems a bit strange. I would prefer a better answer from people actually running pre-war BMW's though and not just someone who has a bike from the 1970's.

Thanks
Chris

Bruce Frey
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VBMWMO #6316
Texas Hill Country, USA
Joined: 10/27/2006
Posts: 574
I have not used any fuel

I have not used any fuel additive in my pre-war bikes. No problems, but these are not high mileage bikes, either.

If my information is correct, the Europeans did not use tetra ethyl lead until after WW2 because of its toxicity. Alcohol was the initial octane enhancer.

Bruce

Chris_T
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Lancashire, UK
Joined: 01/27/2016
Posts: 5
Thanks Bruce The R4 I have

Thanks Bruce

The R4 I have just purchased has 24000km on the clock so not exactly high mileage so I assume normal 95 ron unleaded would be fine or would you advocate using 98/99 ron?

Bruce Frey
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VBMWMO #6316
Texas Hill Country, USA
Joined: 10/27/2006
Posts: 574
I should have said I don't

I should have said I don't use a lead additive. I do use Stabil, a fuel stabilizer, to help storage life.

In the past, I also experimented with adding 2 stroke oil (about 100/1) with no discernible difference.

My R12 and R6 run on low octane (87 USA) pump gas and seem happy. These are very low compression engines.

Bruce

Darryl.Richman
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VBMWMO #6285
Surf City, USA (Santa Cruz, CA)
Joined: 10/27/2006
Posts: 2183
I run regular unleaded in my

I run regular unleaded in my old BMWs, and I've put 22k on my /2, 10k on my /3 and 10k on my 1928 R52. I live in California, and all gas here is E10.

Although adding lead was common in the US from the 1920s, my understanding is that this was not common in Europe until after WWII.

During WWII, the German government had all vehicles accepted for the war effort marked with the required octane level in the fuel. For BMW motorcycles, most were marked OZ-74, though the R66 model required OZ-80. I don't know how comparable German octane numbers from WWII are with the numbers we see today. Even today, the numbers are different in the US vs. Europe for "equivalent" gas (European octane numbers are about 5 points higher than US numbers). But 74 is very low, no matter how it was measured at the time, so I don't worry about it.

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