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Is it bad to run a drz400sm on premium fuel every day? Im thinking the higher octane might really effect the longevity of the engine over time even with a casual riding style...?
 

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The DRZ only needs the cheap stuff, and won't benefit (at least on a stock motor) from the higher octane.
 

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The DRZ only needs the cheap stuff, and won't benefit (at least on a stock motor) from the higher octane.
Damn Randy...The DZR/R has picked up on one of it's owner's habits on drinkin the cheap stuff!:D
 

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It shouldn't bother the motor at all, or effect the longevity.
 

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whats the CR on the stock 400 motor? my buddy just runs premium no matter what, as do i with the 250 but thats because its a "HC" motor. supposedly. only 11.8:1. yamaha recomends 91 or better and my choices at the pump are 97, 89, or 93. i figgured the DRZ was the same way... guess not
 

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Damn Randy...The DZR/R has picked up on one of it's owner's habits on drinkin the cheap stuff!:D
I didn't know girls bikes came in an R designation. :rofl: The owner gets pickier the older he gets, been hitting the build a sixxer rack at the local watering hole. Whole rack of imports and good stuff for $11 a six pack.

whats the CR on the stock 400 motor? my buddy just runs premium no matter what, as do i with the 250 but thats because its a "HC" motor. supposedly. only 11.8:1. yamaha recomends 91 or better and my choices at the pump are 97, 89, or 93. i figgured the DRZ was the same way... guess not
11.3:1 low octane 87 is what the manual calls for.
 

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I have no idea what my KLX450R calls for, but it has yet to complain about $3.89 per gallon 87 octane. Beggers can't be choosers in my case. :thumbup:
 

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I have no idea what my KLX450R calls for, but it has yet to complain about $3.89 per gallon 87 octane. Beggers can't be choosers in my case. :thumbup:
i dont know what that bike calls for, i know that higher compression motors are supposed to have higher octane, but no idea what the cutoffs are. i guess as long as you dont have any detonation, youre good.

the problem wityh the lower octane fuels in a "high" compression engine is that the lower octane cannot handle as much compression without self igniting before the spark plug fires. never had it happen, or know what it does or sounds like, but according to very reputable factory trained techs and just the research i have done over the years, thats what i got out of it.

we had a guy bring in a brand spanking new gsxr because it was running wierd, and it was the 87 he put in it. but i guess those bikes are just picky.

i would just stick with what the owners manual says or higher. even my truck runs better on 93 but ill be damned if im going to put 26 gallons of it in there every week or 2
 

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i dont know what that bike calls for, i know that higher compression motors are supposed to have higher octane, but no idea what the cutoffs are. i guess as long as you dont have any detonation, youre good.
There arent any guideline "cutoffs" because the required octane for an engine is based on ignition timing and engine speed as well as compression ratio.

The common misconception that engines make more power and/or last longer by using higher octane fuel is complete BS. The lower the octane rating a fuel has the faster it will burn, the faster the fuel burns the more power the engine will make (as long as it does not reach the point of knock/detonation). The thought that a higher octane fuel will make an engine last longer is tied directly into the thought that because something is more expensive it must therefore be of a higher quality, which is of course not true.

That said, I generally run what the owners manual recommends, unless there have been significant modifications to the engine.
 

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I was under the impression the higher 91 octane doesn't contain ethanol and that fuel with ethanol doesn't burn as well at higher rpms. I've always ran premium cause I dont mind paying a little more especially when Im only pumping 2.5 gallons. Maybe I'm just stuck in my ways.
 

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I was under the impression the higher 91 octane doesn't contain ethanol and that fuel with ethanol doesn't burn as well at higher rpms. I've always ran premium cause I dont mind paying a little more especially when Im only pumping 2.5 gallons. Maybe I'm just stuck in my ways.
i can only speak for here, but. ALL the fuel "contains up to 10% ethanol"

thats cheap, mid and premium.
 

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OK, how about a big bore DR-Z with E compression at 5300 ft? I've been running premium in it, because I'm scared I wouldn't know detonation if I heard it. I forgot to ask Eddie when I picked it up. ;)
 

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OK, how about a big bore DR-Z with E compression at 5300 ft? I've been running premium in it, because I'm scared I wouldn't know detonation if I heard it. I forgot to ask Eddie when I picked it up. ;)
Best to ask Eddie as he would know what was done in there. Detonation sounds like marbles banging around inside your cylinder.
 

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Best to ask Eddie as he would know what was done in there. Detonation sounds like marbles banging around inside your cylinder.
So- what you're saying is that I would recognize it. :lol: Probably even over my MRD!
 

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87 or 89 is just fine. My dad actually delivers fuel on a daily basis, so I get a lot of info from him. The biggest octane difference is between 87 and 89. Anything higher than 89 is (99 times out of 100) is just 89 with additives. In other words, 91, 93, etc... come from the 89 tank on the fuel truck, and on the way out of the hose and into the gas station tanks, it gets mixed.
 

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I just put 93 in all of my bikes.

The DRZ has a 1.8 gallon tank, so the difference between 87 and 93, even on an empty tank, is all of.....what, 45 cents, even here in wicked expensive upstate NY? My Deezer is 11 years old and I beat it like it owes me money, and there appear to be no long term effects from running the higher octane stuff.
 

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Higher octane is always better!!! Im 50% race fuel 50% 93 octane. Bike runs better and cleaner! AND ITS BETTER FOR THE MOTOR!!!
 
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