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DR650 High compression piston and low octane 3rd world gas

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hi all,

I have a JE High compression piston installed in my DR. I love the power that she puts out now! I always use Premium fuel.

However, i am contemplating taking my DR down to South america and i know for sure that the octane quality is going to be low and questionable.

While i will take the precaution of using a good inline fuel filter and such, i am wondering about the effects of say 85 Octane on a 10.5:1 compression piston?

Thoughts?

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I don't think that's a good idea, I heard some people are already getting pinging from using regular gas under hard loads.

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+1 Especially if the installer does not bother to check and adjust the squish band dimension if required. .040 to .045" is a good street engine number. Mine was at .05+ with the J&E HC piston. Decked the cylinder .011" to bring it into tolerance.

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effects of say 85 Octane on a 10.5:1 compression piston?

Take some octane booster with you. With that much compression, you need 91 octane (depending on elevation ofcourse) The higher you go, the less octane you need.

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+1 I lived in South American for many years, and I think you'll find that you can find medium grade or premium in all except the most remote places. It's not as bad as you might think, in fact some California premium seems actually worse than what you find down there. So just take some octane enhancer and carry it along. You'll be able to find it in specialized auto supply stores in the cities as well to re-stock during the trip.

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Thanks all. Its good to know the options. I spoke with Jesse at keintech and he mentioned that one precaution was to add a thicker base gasket (he is having one ordered from a gasket maker) to reduce compression. Ofcourse, this means taking apart the engine, but atleast it means i wont have to put in a stock piston and break that in again.

glad to know about good gas down south. just dont want to take a chance. one of these days i am going to try 87 octane and see what it does...

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Doesn't Jay have your motor in his bike? I thought his motor blew up or had some major problem? Did you manage to get it fixed? What was the issue and solution?

Good for you if you fixed it! ;)

I remember before Jay left (Jammin) I worried about his modified high comp.

motor. And I remember you guys did an engine swap in record time. Nice work!

New gasket is your best solution I guess. :eek:

My DR has never, ever pinged on any gas ... including barrel gas in Baja. There was crap and rust in that gas but never got pinging. Now, even in Baja, high test gas is more and more available in bigger towns.

On mainland Mexico "Extra" is nearly everywhere now. Even small-ish towns.

I used it later on in my DR only because my MPG really improved running the higher octane fuel.

IIRC, most of Cent. America has high octane gas. But out in the boonies? Who knows? Not sure about S. America but as stated above, I think its better situation now. But deep in the Andes, way off the beaten path, I doubt you will find high Octane ... or much gas at all.

I do know they sell all kinds of Octane boosters all over Mexico, most left over from years of never having high octane fuel. Now they have high octane but the Booster products are still around. No idea which are good or bad. Never bought any.

Maybe you can just fly down and take over Jay's bike when he is finsihed traveling? :banana: Good luck finding a solution to this!

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54321,

indeed, Jay has my motor and it is doing very well down there in Brazil right now. Actually his motor blew up because he forgot to release the cam chain tensioner when putting it back in. It was a simple oversight that neither he nor the mechanic knew of. Lucky for him i had my DR around.

Actually the credit goes entirely to Mike (Mfed on here) for swapping the engines out, hosting Jay for a couple nights and sending him safely on his way. Mfed then went way out of his way and helped me procure a DR motor, and then drop in some nice tasty bits into it. He poured dozens of hours of his time into my DR. Its running like a frickin champ right now and i love it dearly.

when putting in the high-comp piston in, i did not have any major intentions of 3rd world travel, but now that i have been so involved in the bike's rebuild, i feel its the ideal machine to take abroad instead of my vstrom 650 that has been my loyal companion.

Glad to know the fuel down there is do-able and getting better. I am still ways off going off to s.america. Just for peace of mind, i might drop in a thicker base gasket in and call it a day. Once i come back, i can swap base gaskets back just to get the power back again.

thanks all for the inputs. highly appreciated.

Doesn't Jay have your motor in his bike? I thought his motor blew up or had some major problem? Did you manage to get it fixed? What was the issue and solution?

Good for you if you fixed it! ;)

I remember before Jay left (Jammin) I worried about his modified high comp.

motor. And I remember you guys did an engine swap in record time. Nice work!

New gasket is your best solution I guess. :eek:

My DR has never, ever pinged on any gas ... including barrel gas in Baja. There was crap and rust in that gas but never got pinging. Now, even in Baja, high test gas is more and more available in bigger towns.

On mainland Mexico "Extra" is nearly everywhere now. Even small-ish towns.

I used it later on in my DR only because my MPG really improved running the higher octane fuel.

IIRC, most of Cent. America has high octane gas. But out in the boonies? Who knows? Not sure about S. America but as stated above, I think its better situation now. But deep in the Andes, way off the beaten path, I doubt you will find high Octane ... or much gas at all.

I do know they sell all kinds of Octane boosters all over Mexico, most left over from years of never having high octane fuel. Now they have high octane but the Booster products are still around. No idea which are good or bad. Never bought any.

Maybe you can just fly down and take over Jay's bike when he is finsihed traveling? :banana: Good luck finding a solution to this!

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