Bad Gas == Bad JuJu

[Pat Kelly]

87 octane unleaded with no problems. I heard of research done by members of the Porsche Club on unleaded fuel on original leaded engines. The conclusion was that there was no need to have hardened valve seated installed in the head.

As to the title of this thread:
I don't remember what I ate that day but I once had "bad gas".... bad enough that it caused my wife to vomit. My kids and I thought it was funny, wife didn't.

[DiverRay]

The XS1100E was designed to run on REGULAR/UNLEADED gas. High octane does NOT burn correctly, and can cause carbon buildup on the pistons and heads. I run 76 or Chevron in my bikes, and have no problems.

[crazy steve]

You guys run on unleaded?

Thought a major conversion needs to be done to get that done. I run on what is called lead replacement petrol over here. If you guys can vouch that she will run on unleaded, then I don't have to drive all over to find a fuel station that sells LRP

When these bikes were introduced in the US in '78, leaded fuel was pretty much gone, so unleaded was usually your only choice. I'm pretty sure the owners manual stated that unleaded was recommended. But for sure, that's all I've ever ran. If a motor will tolerate unleaded, it's actually better as it leaves far fewer deposits behind.

And I usually ran regular grade, as I never saw anything more than very slight mileage/performance gains with higher-octane fuel. Certainly not enough to justify the higher price. But my bike was/is stone-stock, so if you've tuned for more power you may need the higher grades.

'78E original owner

[crazy steve]

... I heard of research done by members of the Porsche Club on unleaded fuel on original leaded engines. The conclusion was that there was no need to have hardened valve seats installed in the head...

Take that with a grain of salt. If the motor has aluminum heads with a pressed-in valve seat, yes, this is nearly always true. But if you have an older motor (pretty much anything pre-70s) with cast iron heads where the valve seat is machined directly into the casting, unleaded fuel can be an issue as the metal wasn't always hard enough to take the higher heat and lack of lubrication.

'78E original owner

[Athedra]

So a '79 standard (European) should handle unleaded no problem?

[crazy steve]

Absolutely.

'78E original owner