Carb problems following needle shim mod

[Sarris]

91 octane under the RON must be regular. MON regular octane must be must be 83. 91+83=174/2=87 Average Octane in the US

Some countries (like Canada) use just the RON measurement. All the same stuff measured with a different scale.

Also, what thay are saying is don't use less than "91 RON octane regular", as 60 octane donkey piss is available in some asian subcontinent areas.

Confusing, eh??

[Easy Rider]

Originally Posted by Jere

Now, it says "or higher." Why would it say that if premium was not good for it?

So.....who/where does it say that premium is "not good for it" ???

Some specific bikes don't run quite as good with it; a scant few seem to run better......but none will be harmed.

It is a waste of money but not dangerous.

[alantf]

Originally Posted by Easy Rider

Now, it says "or higher." Why would it say that if premium was not good for it?

I seem to recall an answer to this a few months back (but I can't remember which post) when someone (again, I can't remember who) explained that the higher octane fuel exploded with a sudden bang (due to some chemical or other) while the lower octane gave a "slower" burn, which the gz engine appreciated. :roll:

[Easy Rider]

Originally Posted by alantf

I seem to recall an answer to this a few months back (but I can't remember which post) when someone (again, I can't remember who) explained that the higher octane fuel exploded with a sudden bang (due to some chemical or other) while the lower octane gave a "slower" burn, which the gz engine appreciated. :roll:

Good.......kind of. O_o

It's exactly backwards. That's why you need the higher octane in a HIGH compression engine.......which the GZ is NOT !!

[Sarris]

Here is a good article on octane.

http://en.wikipedia.org/wiki/Anti-Knock_Index

[Water Warrior 2]

Originally Posted by alantf

I seem to recall an answer to this a few months back (but I can't remember which post) when someone (again, I can't remember who) explained that the higher octane fuel exploded with a sudden bang (due to some chemical or other) while the lower octane gave a "slower" burn, which the gz engine appreciated. :roll:

Higher octane gas has a fast controlled burn for high compression engines. The chemical /additive package controls the burn rate.

[Jere]

Originally Posted by Easy Rider

So.....who/where does it say that premium is "not good for it" ???

Some specific bikes don't run quite as good with it; a scant few seem to run better......but none will be harmed.

It is a waste of money but not dangerous.

I don't believe anyone's used those exact words, but earlier in this thread mrlmd1 explicitly said "do not use premium gas" and even suggested that someone should empty the gas out and put regular in.

[Easy Rider]

Originally Posted by Jere

but earlier in this thread mrlmd1 explicitly said "do not use premium gas"

and even suggested that someone should empty the gas out and put regular in.

Yes, it is generally good advice to NOT use premium gas in an engine that doesn't need it.

And, it is generally good advice to drain the tank when you suspect you are having a fuel problem.

Try not to read things in the messages that are not there !! :biggrin:

[Jere]

I'll follow your advice. It's just natural for me to assume when someone says not to do something it's because it's bad.

I still don't understand why using premium gas is not recommended though. Anyway, doesn't really matter I guess. I appreciate the advice.

[Sarris]

It's not recommended because your GZ has low compression and does not require the octane to slow combustion.

This is why the use of high octane fuel in the GZ may result in slightly lower performance and slightly lower mpg.

High compression engines need octane to slightly retard combustion so it doesn't spontaneously ignite (ping) during the compression stroke under load.

Read the article I sighted in the above post.