What octane gas do you run in your 250r?

**ATC350X 85** · 08-05-2003, 03:39 PM

I have an 86 250r that is bored .25mm over (.010 over) with a factory honda piston, an old school answer silencer and uni filter. I run Sunoco 94 octane at 40:1 with bel ray mc:1

**86250RZ** · 08-05-2003, 04:56 PM

I have an 86 250R W/LRD 295 big bore kit W/ MX port job, shaved head, 39mm Air striker carb. Boyesen Rad Valve W/carbonfiber reeds, Dial-A-jet, No air box K&N W/ Outerwear and FMF Fatty Pipe W/Power Core silencer and I run 112 VP at 32 to 1 W/ Castor 927 oil.

**MR ATC** · 08-05-2003, 05:32 PM

I rum VP C12 mixed with maxima 927 at 32:1

the motor mods include...
.080 over piston
lighter crank
higher compression
ported
CR gaskets
balanced/blueprinted
Rad valve
Paul Turner pipe/silencer or phase 5 pipe and comp 2 silencer
39mm pwk carb
CR 250 ignition (no lights, lighter flywheel)

**Mobular** · 08-05-2003, 07:27 PM

Stock 82 250R with 87 octane and Torco mix. Runs just fine!

**YTZ250#1** · 08-05-2003, 09:11 PM

mine is a 265 with full porting and after market head.I run 115 octane
turbo blue with klotz r 50 at 32:1

**atc86r** · 08-05-2003, 11:00 PM

114

**2strokepwer** · 08-05-2003, 11:11 PM

110 blue thunder

**200x Basket** · 08-06-2003, 04:27 AM

93 at 40:1 PJ1 synth. and it runs great!

**ATC350X 85** · 08-06-2003, 10:47 PM

MR ATC, for what my 250r has done to it, is what Im running good in your opinion? It runs strong, i was running 102 and 94 mixed 50/50 and it ran just about the same but was killing my $$ so i went back to 94

**Bill X_R** · 08-06-2003, 11:25 PM

Not one person posted what there comp ratio was...Isn’t octane grade determined from this?, and anything above that is a waste of money? I guess you could argue that it may run cooler therefore more efficient. I think that’s minimal at best.

Hmmm

**200x Basket** · 08-06-2003, 11:59 PM

Originally Posted by Bill X_R

Not one person posted what there comp ratio was...Isn’t octane grade determined from this?, and anything above that is a waste of money? I guess you could argue that it may run cooler therefore more efficient. I think that’s minimal at best.

Hmmm

compression ratio on a ywo strok is way more complicated then on a 4 stroke. the static compression my be low but with the back pressure on the pipe it may be 12:1. it gets tricky.

**MR ATC** · 08-07-2003, 01:09 AM

Originally Posted by ATC350X 85

MR ATC, for what my 250r has done to it, is what Im running good in your opinion? It runs strong, i was running 102 and 94 mixed 50/50 and it ran just about the same but was killing my $$ so i went back to 94

for your motor 94 octane is more then sufficant.

you can run CR 250R head and base gaskets to bump up the compression a little bit and still get away with 94 octane.

you wont have to go higher on octane untill you have your head shaved or the dome reshaped.

also if you used TRX 250R gaskets you lowered your compression

**YTZ250#1** · 08-07-2003, 07:23 AM

Not sure of ratio,But it has over 215psi of compression.I was told to run between 110 and 120 octane.

**Klendathu** · 08-07-2003, 02:04 PM

I run my 250R with 92 octane and Motul 600 oil mix 1:32 and it run well and strong. Still got the original 1985 piston on.

**Manny55** · 08-07-2003, 02:27 PM

My R is 21 years old i havnt had to bore it or anything the only thing i have done to it is rebuilded the carb

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What octane gas do you run in your 250r?