Only 87 oct. gas available on long D/S ride.

Got questions? We got answers....
Post Reply
TheRadBaron
Supporting Member II
Supporting Member II
Posts: 267
Joined: 10:21 pm Nov 07 2012
Country:

Only 87 oct. gas available on long D/S ride.

Post by TheRadBaron »

I have a dual-sport ride this weekend in southern Indiana and I plan to ride my '89 KDX200. All the fuel stops are in small towns and 87 octane gas is all that will be available. I always run premium gas and I'm nervous about using 87. Does anyone here have any experience using 87 in their KDX? Any pinging or other trouble? I have a DG pipe and RB carb and head if that would matter.
I did some research on octane booster and found that toluene is the main ingredient in most of them. 10% toluene is supposed to add 2 full octane points and I even have a jug of it at home. The problem is that I'd have to carry almost a gallon of it to get my octane up for the whole trip.
What do you guys think?
Is 87 alright or is it asking for engine damage?
dualscotty
Member
Posts: 115
Joined: 09:49 am Oct 12 2014
Country:

Re: Only 87 oct. gas available on long D/S ride.

Post by dualscotty »

I have a 98 kdx 200 that is plated. I do a lot of dual sport trips on it. My bike is completely stock. I run the high octane just because it's easy to choose it at the pump. I have however run the regular low octane gas before for a long time and have seen no performance advantage nor damage to the engine.
User avatar
KDXohio
Supporting Member
Posts: 825
Joined: 06:04 pm Jun 19 2013
Country: United States
Location: Dayton, Ohio

Re: Only 87 oct. gas available on long D/S ride.

Post by KDXohio »

87 resists pre-detonation to around a 9:1 compression ratio over that and you need a higher octane. I believe the 90+ KDX is around 9-9.5:1
So you may get slight pre-detonation but probably not something you would notice unless you've had the head milled (increases compression ratio) or a fresh top end.

Personally I wouldn't worry to much about it..but if you are worried drain your tank and put some 87 in there and warm it up and see how it does.
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
User avatar
KDXohio
Supporting Member
Posts: 825
Joined: 06:04 pm Jun 19 2013
Country: United States
Location: Dayton, Ohio

Re: Only 87 oct. gas available on long D/S ride.

Post by KDXohio »

Image
1990 KDX200 FMF Fatty, Answer VFC silencer, VForce 3 Cage, Wiseco Piston, KX125-J series KYB USD fork conversion, Race tech goldvalves, J series front brake assembly, air-box snorkel removed, Acerbis Headlight, KX450F Front fender, Pro Taper RM bend bars, ASV front Brake lever, MSR Clutch perch and lever, RB Head mod, 36mm PWK carb, Trail Tech Kickstand.
User avatar
Slick_Nick
Supporting Member
Posts: 1675
Joined: 10:06 pm Oct 22 2009
Country: Canada
Location: Calgary, Alberta
Contact:

Only 87 oct. gas available on long D/S ride.

Post by Slick_Nick »

Just to be safe, why not retard the timing for your trip? As a plus you'll get more over-rev! :grin:
'00 KDX 220R
TheRadBaron
Supporting Member II
Supporting Member II
Posts: 267
Joined: 10:21 pm Nov 07 2012
Country:

Re: Only 87 oct. gas available on long D/S ride.

Post by TheRadBaron »

Thanks for the info, guys. Retarding the timing a bit might not be a bad idea but I think I've managed to work out some logistics so that I'll only have to fill up with 87 at two gas stops. I'm going to carry a quart of toluene with me and stash another quart at one of the gas stops before the ride. This will let me get the fuel up to about 90 octane. I think that should be alright.
User avatar
fuzzy
KDXRider.net
KDXRider.net
Posts: 3437
Joined: 01:29 pm Jun 18 2003
Country:
Location: Fredneck, MD

Re: Only 87 oct. gas available on long D/S ride.

Post by fuzzy »

Most likely as long as you don't wring it out a ton you won't have any problems. Hear detonation, back off!
'91 KDX 200 Project $300 KDX
'95 KDX 200 Project $600 KDX
'94 WR 250 Always a project
pumpguy
Gold Member
Gold Member
Posts: 821
Joined: 10:00 am May 29 2012
Country:
Location: Spring Grove, Illinois

Only 87 oct. gas available on long D/S ride.

Post by pumpguy »

Be sure you follow this advice. One time I didn't, and ended up with a nice hole in the piston crown.
User avatar
C George
Supporting Member II
Supporting Member II
Posts: 550
Joined: 04:50 pm May 09 2013
Country:
Location: Vermont

Re: Only 87 oct. gas available on long D/S ride.

Post by C George »

KDXohio wrote:Image

Excellent Chart , The new 4 stroke engine design " combustion " makes this a little dated as those dam
things can run a 12:1 engine on 91 octane all day. I'm not an engineer but it has to do something with the
Indy Car engine model.

Sorry to sway your thread :)

87 on a stock engine , you should be fine.
05 KDX-220R / 06 KDX-225R / Maxima 927 / Millenium Tech / Ron Black / PC , FMF / Many 220 engine mods / 40 + yrs. of riding dirt bikes 🤟🤟
User avatar
C George
Supporting Member II
Supporting Member II
Posts: 550
Joined: 04:50 pm May 09 2013
Country:
Location: Vermont

Only 87 oct. gas available on long D/S ride.

Post by C George »

Back to your initial question ,,, Pick up some qts. of NON-ethanol 94 / 95 octane fuel at your local small engine / John Deere / or auto parts house.

Something you could put in a back pack.
05 KDX-220R / 06 KDX-225R / Maxima 927 / Millenium Tech / Ron Black / PC , FMF / Many 220 engine mods / 40 + yrs. of riding dirt bikes 🤟🤟
Bitteeinit
Member
Posts: 360
Joined: 11:44 pm Jul 12 2014
Country:
Location: Cambodia

Re: Only 87 oct. gas available on long D/S ride.

Post by Bitteeinit »

I highly doubt it would be a problem. I often bought shitty gas sold out of empty glass Coke bottles on the side of roads here, and never had any visible issues. I'm sure the 87 octane you'll be buying from actual pump stations will be way better than old dirty gas I buy that's sitting out in the sun all day.
Post Reply