Fuel Grade

[PolygonFla]

Hi everyone,

As most of you already know, I burned a valve on my Zongshen sierra not to long ago.

It happened while crossing a long bridge at 65 mph (WOT) on a very hot day. (mid 80s)

I just got back from the dealer who if fixing it under warranty and found out that the parts are expected next week.

The deal said that Zongshen wanted to know what grade of gas I have been using. And to pass on to me that I should only use low octane fuel. Apparently the higher the octane the slower the burn thus reducing knock in high compression engines. However the Zongshen has a low compression engine and the fuel is still burning when the exhaust valve opens. causing power loss, engine over heating and valve damage.

Who woulda thunk it?

[liverchip]

What are they meaning by lower octane? 89, 87, or as low as 86?

[PolygonFla]

They said run 86 in it.

The octane rating listed in the manual is the European/Asian number and that it is higher than the US system. 86 here equals 92 every where else. :o

I am tempted to say that our bikes are happier with the cheap stuff but 86 octane isn't so cheap any more :(

[liverchip]

We're at 3.25 to 3.30 a gallon here in CA.

[FMYStreetRacer]

i've been running 93 in mine for a while now and nothing has happened so far. i have been thinking about switching down to the 87 stuff though.

[Savage]

We were told to run 91+ or you would foul up your plugs and your bike wouldn't like it.
More info would be nice

[ejcycles]

The octane rating listed in the manual is the European/Asian number and that it is higher than the US system. 86 here equals 92 every where else.

Ok the A. Lifan owners manuals says: Fuel: Unleaded Gasoline with RQ-93 or higher.
There are three different ways to figure octane ratings...Read This>
http://www.geocities.com/motorcity/l...0/octane1.html

Bruce

[FreightTrain]

Originally Posted by PolygonFla

Hi everyone,

As most of you already know, I burned a valve on my Zongshen sierra not to long ago.

It happened while crossing a long bridge at 65 mph (WOT) on a very hot day. (mid 80s)

I just got back from the dealer who if fixing it under warranty and found out that the parts are expected next week.

The deal said that Zongshen wanted to know what grade of gas I have been using. And to pass on to me that I should only use low octane fuel. Apparently the higher the octane the slower the burn thus reducing knock in high compression engines. However the Zongshen has a low compression engine and the fuel is still burning when the exhaust valve opens. causing power loss, engine over heating and valve damage.

Who woulda thunk it?

doesn't make sense... higher octane = a faster burn, not slower. Plus air-cooled engines also run cooler on premium due to the faster more complete burn

its the FASTER more complete burn of premium that REDUCES knock. same as in a hi-performance auto.
and same as in a high performance auto, the SSLOWER burn of lower octane causes knock

have you fiddled with your carb settings or jets? could be slobbering rich and or timing might be a bit off which could also cause unburned fuel passin the valve

[Penguini66]

What about the Lifan engines? I can't remember what the manual says (If I even knew where the manual was). The site I bought the bike from (HooperImports), has a scan of the EPA sticker and it says "RESEARCH OCTANE NO. 89 MIN" (That should be a RON of 89). Now, what that 89 means is totally up to speculation. While one would hope that the Chinese understood our rating system over here, one would also assume that there is a high chance that they might have gotten it wrong.

From Wikipedia: http://en.wikipedia.org/wiki/Octane_rating

In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe.

So, the label on my Lifan could be interpreted one of two ways:
1. The octane of RON89 on the sticker is actually a true RON89 rating and you should be able to use fuel 4 to 5 points lower.
or...
2. The Chinese actually took the time to convert the octane rating to the (R+M)/2 standard that we have here in the US but didn't know enough to say that on the label.

I started out running 87 and found that I got a little pinging going up hills under load so I tried 89. It seemed to eliminate the pinging but, to tell you the truth, its a little hard discerning pinging form any other noise and vibration so I'm not really sure. I plan to go back to 87 this season unless I think I hear pinging again.

Oh, and for anybody who's not all that farmiliar with Octane, definately read that Wiki. But in short there's one thing that is important that many people seem to not understand: Running a higher octane fuel than necessary for the compression of the engine is a complete waste of money and does not offer any performance gains. From what I understand, since higher octane fuel has less energy, it will actually produce less power than a lower octane fuel.

[FMYStreetRacer]

doesn't make sense... higher octane = a faster burn, not slower. Plus air-cooled engines also run cooler on premium due to the faster more complete burn

its the FASTER more complete burn of premium that REDUCES knock. same as in a hi-performance auto.
and same as in a high performance auto, the SSLOWER burn of lower octane causes knock

have you fiddled with your carb settings or jets? could be slobbering rich and or timing might be a bit off which could also cause unburned fuel passin the valve

man you have that all backwards.


BTW what is the actuall compression and timing of our engines? i have the over head cam engine.

[cycleway4]

I second with FMY!.......all backwards

high octane=slower burn

I agree......these bikes only need 87

[FMYStreetRacer]

Originally Posted by cycleway4

I second with FMY!.......all backwards

high octane=slower burn

I agree......these bikes only need 87

what tooth rear doy do you have? i have a 42t rear and i run 93 just cause i'm worried of the load that i'm putting on the bike during acceleration. i don't want any detonation. plus i haven't put the bike on the dyno yet to see what my actuall a/f is. i need a m/c sniffer so that i can hook my wide band to it and take it for a spin.

[Penguini66]

Originally Posted by FMYStreetRacer

BTW what is the actuall compression and timing of our engines? i have the over head cam engine.

I believe that for the Lifan 163FML-2 it is 9.0:1

Edit - Found the link: http://www.hooperimports.com/product.asp?pf_id=E2005M

[Penguini66]

Originally Posted by PolygonFla

The deal said that Zongshen wanted to know what grade of gas I have been using. And to pass on to me that I should only use low octane fuel. Apparently the higher the octane the slower the burn thus reducing knock in high compression engines. However the Zongshen has a low compression engine and the fuel is still burning when the exhaust valve opens. causing power loss, engine over heating and valve damage.

Personally, I think either Zongshen or your dealer is feeding you a line of BS. Either that or Zongshen's real point was simply lost in translation. I'm certainly no expert but I've never heard of higher octane creating the type of damage you experienced. And if you think about it, don't most vehicle manuals list a "minimum" octane rating? If it were dangerous to use higher octane, why would they say minimum?

[Jim]

I've been using premium, not sure what it is octane wise.... The guy I got it from said I might aswell use the premium when I bought mine, but then he told my dad and his friends when they bought theirs they could use whatever gas... So I don't know what he really recomends...
So far no problems with the premium, but I dont have too many k's yet...