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i was thinkin about running AV gas in my 00 cr 250.

Does anyone have any objections?

do i have to re-jet the carb?

do i have anything to be concerned about?

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i was thinkin about running AV gas in my 00 cr 250.

Does anyone have any objections?

do i have to re-jet the carb?

do i have anything to be concerned about?

No,

Probably,

No, but it probably isn't going to give you any increased performance, and it may not run as crisp as pump gas does. If your bike truly needs higher octane than you can get at the pump, you'll be better off buying a race fuel. AV gas has stuff in it that is specific to aeronautics and altitude--stuff that your bike isn't going to thrive on.

If your bike doesn't need the higher octane, then it's all just burnt money.

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I run it in all of my 2 strokes. (The CRs have the head squish fixed and setup for AVGas, the KTM is stock as well as my son's 65 and 85).

Jetting for mine changed a bit, I ran the MJ one step leaner and mix @ 40:1. Stay away from any non synthetic premix (it will separate from the AVGas), I run motul 800 and it has never separated even sitting in the can for weeks.

Great alternative to race gas (much cheaper here where I live in SoCal). As for it not being as crisp I have never run into those issues. It won't give you any more power if you aren't setup to use it, just like any other race gas.

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I found that AV 100LL works well in my cr 480. If you have a bike that pings, and is hard to jet it helps (cr 480's are known for these traits). If you are looking for a performance improvement with the stock engine, it won't help. I did find that mine ran better and cooler on Torco 110 than Av 100LL. Easier to jet as well. I would rather spend the $8 PER GAL ON Torco than $5 on AV.

That said, my friend rides a 2000 cr 250 that runs great on pump, and he rarely has to change a jet.

The jetting change is small, perhaps 1 step leaner on the main/clip with AV vs pump.

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yes the 100LL is the fuel i have access to. 100 octane Low Lead. i might give it a whirl. or mix it 50/50 with premium.

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I have been using 50/50 with 93 pump gas. The ping is gone and I did have to mess with the jetting just slightly. Also, it does like to separate the premix and fuel at around 32 degrees Fahrenheit. At least that is what I have read here and on fuel information sites.

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Also, it does like to separate the premix and fuel at around 32 degrees Fahrenheit. At least that is what I have read here and on fuel information sites.

That's only with castor based oils like 927. You have to be careful with castor based oils because at lower temps, they will separate out of fuels that have a specific gravity of less than .730, which includes a lot of race fuels.

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sweet. i just bough 10L today of the 100LL from my neighbour. he runs a spray plane business.

me and buddie are gonna dump some in out bikes this evening and go for a rip.

00 cr250

06 sx250

:smirk: im excited

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figured id bump this thread with some info i found. i also high lighted the octane info since i know some are strictly looking for this info and will skim over the info looking for it. also shows how mixing it with different % of 91 octane results in what type of final octane rating. seems 25% avgas to 75% premium would be the idle mixture for most 250's (my honda requies 92 octane and i have no where to buy it in cali) and a mix of 50/50 would work perfect for some of the 125's (my friends 97 yz125 requires 95 octane). just enough octane to be above the spec but not enough to get any of the negative effects of running overly high octane gas in stock engines.

http://backcountryrebels.com/showthread.php?t=3793

Not sure where to put this.

Bunch of info I scrounged up on Avgas. Just to get the facts out instead of everyone not knowing.

Heres some info from conoco phillips. Look down to the octane lean. That is the MON rating.

http://www.experimentalaircraft.info...vgas-specs.pdf

Additives - AO Antioxidants mg/gal 45.4

Additives - Conductivity Conductivity Improver 842

Additives - Dye Blue Dye mg/gal 10.2 805

Additives - General Note General Note 878

API Gravity (60 Deg F) D 4052 Density & Rel Dens API Report

Appearance D 4176 Wtr & Part Cont, Proc 1 Pass 841

Color, Visual D 2392 Color of Dyed Av Gas Blue

Copper Strip Corrosion D 130 Cu Str 2 Hr @ 212 F Rating 1b

Dist 10 Vol% Evap D 86 Dist at Atm Press Deg F 167

Dist 10%+50% Evap D 86 Dist at Atm Press Deg F 275

Dist 40 Vol% Evap D 86 Dist at Atm Press Deg F 167

Dist 50 Vol% Evap D 86 Dist at Atm Press Deg F 221

Dist 90 Vol% Evap D 86 Dist at Atm Press Deg F 275

Dist End Pt, corr D 86 Dist at Atm Press Deg F 338

Dist IBP, corr D 86 Dist at Atm Press Deg F Report

Dist Loss, corr D 86 Dist at Atm Press Vol% 1.5

Dist Recov, corr D 86 Dist at Atm Press Vol% 97

Dist Residue D 86 Dist at Atm Press Vol% 1.5

Freeze Pt D 2386 Freeze Pt by manual Deg C -58 808

Lead (Pb) D 5059 Lead by X-ray Spec gPb/gal 2.12

Lead as TEL eq D 5059 Lead by X-ray Spec ml TEL/gal 2.00

Net Heat of Combustion D 3338 Net Heat of Comb BTU/lb 18,720 835

Octane, Lean Number D 2700 Knock Charac by Motor 99.5

Octane, Performance No. D 909 Knock by Supercharge 130.0 809

Ox Stab, Lead Precip D 873 Ox Stab, 5 hrs aging mg/100ml 3 851

Ox Stab, Potential Gum D 873 Ox Stab, 5 hrs aging mg/100ml 6 851

Sulfur D 2622 S by X-ray Fluo Spec Wt% 0.05

Vapor Pressure (ASTM D 5191 VP Grabner (ASTM eq) psi 5.5 7.1

Water Rxn Vol Change D 1094 Water Rxn by manual ml + or - 2

Other - See Note Referee Methods 826

Other - See Note Test Tolerances

From Shell

http://www.docstoc.com/docs/7671746/...nd-Avgas-100LL)

Typical Properties

Property

Max Value

Min Value

Knock Rating, Lean Mixture (Motor Method) Octane Number 99.5

Knock Rating, Rich Mixture (Supercharge Method) Performance Number 130

Freezing Point ºC -58

Distillation end point ºC 170

Reid Vapour Pressure @ 38ºC kPa 49 38

Sulphur content %m 0.05

Tetraethyl lead content gPb/l Avgas 100LL 0.56

Colour Blue

From BP, Though I have found other literature from BP stating that the Motor octane is 99.5 minimum, this is what is shown.

http://www.bp.com/liveassets/bp_inte...ok_04004_1.pdf

BP AVGAS 100LL

Specifications

British Def Stan 91-90

USA ASTM D910

Typical Properties

Knock rating

Lean mixture, aviation rating 105

Rich mixture, supercharge method 133

Tetraethyl lead, gPb/l 0.52

Colour Blue

Specific energy, net, MJ/kg 43.73

Density at 15ºC, kg/m3 715

Distillation

Initial boiling point, ºC 41

10% vol. evaporated at ºC 58

40% vol. evaporated at ºC 92

50% vol. evaporated at ºC 101

90% vol. evaporated at ºC 128

Final boiling point, ºC 156

Sum of 10% and 50% evaporated temperatures, ºC 164

Recovery, % vol 98

Residue, % vol 1

Loss, % vol 1

Vapour pressure, kPa 41.6

Freezing point, ºC below -60

Sulphur, % mass 0.0003

Copper strip corrosion (2h at 100ºC) 1

Existent gum, mg/100ml 1

Oxidation stability

Potential gum, mg/100ml 0.5

Lead precipitate, mg/100ml 1.0

Water reaction

Volume change, ml Nil

Interface rating 1

Just to compare here.

Pump gas "87" octane regular is 82-83 MON or motor octane

Super or "92,93" octane is 87-88 MON.

The only race gas that I know is Sunoco 110 which is 105 MON

This was a post by hammer on totally yamaha a few years back. Now I wouldnt argue with this gentlmen about much.

Tuesday, 31 January 2006

The following results were compiled by Intertek (fuel testing service)

OBJECTIVE:

To establish the RON (research octane number) and MON (motor octane number)

MON number is a better indication of fuel quality because it is more representative of high rpm, high load, conditions. The closer the RON and MON are the more stable the fuel is.

METHOD:

Use of CFR research engine with variable compression.

All test work carried out to ASTM D2699/D2700 standards.

RESULT:

100LL (Avgas) 100.5 MON and 103.2 RON (101.5 AKI)

91 premium unleaded 86.7 MON and 95.8 RON (91.2 AKI)

75% Avgas + 25% premium unleaded 92.9 MON 101.5 RON (97.2 AKI)

50% Avgas + 50% premium unleaded 91.6 MON 100.3 RON (95.9 AKI)

25% Avgas + 75% premium unleaded 88.5 MON 98.8 RON (93.6 AKI)

===============================================

Examples of fuel properties:

Sunoco 110

Specific Gravity 0.72

Research Octane 115

Motor Octane 105

Reid Vapor Pressure 8.0

Boiling Point (liquid to vapor)

10% Evaporation 160

90% Evaporation 260

100LL (Avgas)

Specific Gravity 0.67

Research Octane 103.2

Motor Octane 100.5

Reid Vapor Pressure 7.0

Boiling Point (liquid to vapor)

10% Evaporation 75

90% Evaporation 135

Torco 100 (Unleaded oxygenated)

Specific Gravity 0.75

Research Octane 101

Motor Octane 100

Reid Vapor Pressure 8.0

Boiling Point (liquid to vapor)

10% Evaporation 133

90% Evaporation 205

VP C10 (Unleaded non-oxygenated)

Specific Gravity 0.76

Research Octane 104

Motor Octane 96

Reid Vapor Pressure 1.9

Boiling Point (liquid to vapor)

10% Evaporation 212

90% Evaporation 266

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No need to mix with pump gas. Run it straight with your premix. Nothing will happen and jetting is normally the same as the pump gas. I had a quadzilla that was ported and loved the 100LL. Pump gas it ran like shit. It's not going to hurt anything.

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I have used 100LL in my CR250 for years with no problems. One nice thing about Av gas is that it stores better than pump gas. I don’t ride my 2 stroke often so it’s nice not to worry about old fuel. 

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