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Discussion Starter #1
So I have a 2007 XR650R supermoto, its been an awsome bike for every one of the 8100 miles ive put on it. Lately its been burning a little oil. My first thought was valve seals or rings. So ive been thinking about tearing it down and doing a valve job and a piston and rings, i thought this would be the perfect time to bump up the compression ratio:bike:

Anyway i was dicussing with this local guy about helping me with a valve job, and we started talking about compression and what gas im gona have to run. He said if you go up in the compression at all im gona need more than just 87. And i relized that sense day 1 the bike has been pinging. Normally its only in 5th gear at a low RPM when i wack the throttle hard. I mean at like 3000-4000 RPM and i just open it up. I didnt even relize it was pinging:boxing:. So this guy who works on bikes told me the pinging could be the whole reason that your burning oil:eek::headshake:headshake:headshake

I know the manual suggests 93 octain for the XR, but it always seamed to run great on 87, that pinging can be avioded if you just keep the RPM's high when you wanta accelerate hard. It will never ping in the first 4 gears either. So i suppose im gona start running 93....but will 93 be enough if i bump up the compression to 10:5? 11:1? Its kinda annoying cause my 450 runs awsome with 87. And thats 12:1.

What gas do you guys run in the XRR with what compression?
 

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I have a 2000 XRR and I've always put 91 in mine. It has never pinged and doesn't ever burn oil.
 

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Why run on 87? its a 20 cent difference per gallon to get premium and save your self big money in future repairs.

Do not run anything less than 93, all the mx four strokes I've had would run horrible on anything below 93. My RM seems like it needs even more than 93 when its over 80 degrees out. My 650r will run like crap on anything less than 91, especially in warm weather. mine has to have well over 10,000 miles and does not burn any oil. It should not be burning oil at all at such a low mileage, most likely operator error.
 

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Have your mechanic friend do a leak down test. That will tell you what the condition of the rings and valve seating are.

I don't understand how pinging could cause oil burning. Pinging is a sign that your bike does need more octane. Try doing a tank at 50/50 and see if that satisfy's it.
 

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Discussion Starter #5
Why run on 87? its a 20 cent difference per gallon to get premium and save your self big money in future repairs.

Do not run anything less than 93, all the mx four strokes I've had would run horrible on anything below 93. My RM seems like it needs even more than 93 when its over 80 degrees out. My 650r will run like crap on anything less than 91, especially in warm weather. mine has to have well over 10,000 miles and does not burn any oil. It should not be burning oil at all at such a low mileage, most likely operator error.
Explain this operator error...oh and i have 8300 miles, not a big diffornce to 10,000.
Sorry i dont see how it could be my falt its burning oil, i might just beat the everyliving shit out of the bike.

By the way it runs much better on 93, that was the fix, thanks guys:D
 

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Here is the deal. Pinging is the collision of two flame fronts. one set off by the spark plug, the other set off buy a rise in cylinder pressure from the first combustion. they two explosions hit each other inside the cylinder and make the ping noise. do this long enogh and you will damage a piston. even burn a hole in it if it's bad enough. you usually get enough of a performance gain out of the higher octane to offset the difference in price of fuel. in other words, you get more MPG out of the higher octain, without the damage. always run what they tell you. 11/1 would really be asking for trouble on pump gas!!:infrandom
 

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Explain this operator error...oh and i have 8300 miles, not a big diffornce to 10,000.
Sorry i dont see how it could be my falt its burning oil, i might just beat the everyliving shit out of the bike.

By the way it runs much better on 93, that was the fix, thanks guys:D
I've seen 650r engines come apart with 25000 offroad miles where the piston and cylinder still look perfect. its very hard to kill that engine.

Burning oil was most likely due to all the pinging from running to low of an octane.
 

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i use 95 or 98 octane pump gas in mine all the time... i even feel bad if i use 95 so i just always buy the 98
 

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95 and 98 pump? Where the hell do you live?
 

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i live in the wonderful land of australia our normal unleaded is 91 then preumium is 95 and premium98 is 98 so i never have a problem
 

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91 always...

just bought my 2000 XR650R (2 months), and I have always put 91 in her. Even when I go to baja, these guys always grab the "RED" pump (91)
I have not put anything else, but she runs perfect :bike:and burns no oil. Do you really rev it out, a lot? I was thinking about the 680R big bore kit, anybody do this or have a comment?
 

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i live in the wonderful land of australia our normal unleaded is 91 then preumium is 95 and premium98 is 98 so i never have a problem
I think the rest of the world uses a different octane rating system. North America uses MON and I think Europe/rest of world uses RON.

So 98 outside of the US is 93 in the US. Some of the stations around my area do have 98 and 103 us octane on the pump around street race areas.
 

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98 RON (EU measure) = 93 AKI (US measure)

And for God's sake put some high test in there. Detonation is like taking a sledgehammer to the piston. Hell I mix 100 into mine to get the octane up to 93 or 95 since we only get 91 out of the pump here
 

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Discussion Starter #14
So 98 outside of the US is 93 in the US. Some of the stations around my area do have 98 and 103 us octane on the pump around street race areas.

They do? Where in mass can you find 98 or 103 at the pump?
 

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Just rebuilt my xr600 with 11:1 and it runs great on premium, cant remember if it is 91 or 93. Been running the bike for 4 months now and no problems pinging or otherwise. :bike:
 

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They do? Where in mass can you find 98 or 103 at the pump?
One of the stations by six flags in agawam use to have it at the pump, not sure if they still do. Some of the stations on the Berlin Turnpike in CT have it right on the pump for all the street racers.
 

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. Detonation is like taking a sledgehammer to the piston.
isnt the explosion in there bad enough?

deto isnt good speaking in the long term. for MOST peeps deto is tolerable(read-will get you home if you ping) if its not 24-7 for long periods of time.

deto can cook 2 stroke motors within one hard run (i.e. some of the 2 stroke GP bikes siezing mid-race on hot days....)

everybodys results differ.

do what is right for your altitude/compression/driving demands.

I personally run 85 octane in my hemi ram (93 specified) because Im @ over 6kft elevation on a stock motor. my comp ratio is like
-2million:1
 
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