Gas Octane

[Beau254]

What Octane gas are you guys running on your bikes? I’ve been running that Murphy Non-Ethanol gas because if the bike sets a bit I don’t want the Ethanol jacking up my carbs. But have noticed the bike runs crappy on it. Doesn’t like it. It’s only 87 Octane. I know the Max’s are 10.5:1 Compression. So just curious. May need to add some Octane booster to it. Anybody running 93 Octane? How does it run for ya? Also, I might add that my bike has Stage-7 Jet kit & full UFO Quadzilla Exhaust.

 

[Traumahawk]

If your running a different ECU (Dynajet or ignitech.....with different timing requirement) 87 octane runs WELL in a gen 1. Read the owners manual.....its designed to run on 87 octane. Have you thought that you got bad gas? Now, that being said....the pilot jets on the Vmax carbs are VERY small.....37.5's, so they clog up easily. Ethanol gas ATTRACTS WATER.

Aluminum heads help dissipate heat. Quench design (in the heads) also plays a role in octane requirements.

 

[Ted Drum]

What Octane gas are you guys running on your bikes? I’ve been running that Murphy Non-Ethanol gas because if the bike sets a bit I don’t want the Ethanol jacking up my carbs. But have noticed the bike runs crappy on it. Doesn’t like it. It’s only 87 Octane. I know the Max’s are 10.5:1 Compression. So just curious. May need to add some Octane booster to it. Anybody running 93 Octane? How does it run for ya? Also, I might add that my bike has Stage-7 Jet kit & full UFO Quadzilla Exhaust.

I have run the cheap gas in my 95 and 2017 Vmaxs since new, the last 2 fills before being put away for 6 months winter I fill it with Chevron Supreme that has no Ethanol (lawn mowers also) (ethyl alcohol) is a liquid alcohol typically made from fermented starches or sugars that come from corn or sometimes wheat. It can also come from grassy or woody crops (cellulose), or even garbage.

 

[Pighuntingpuppy]

At my elevation and climate my Gen 1 and gen 2 dont like the 87. Bikes run hotter(at least according to the gauges) and performance seems to suffer a bit. Where I live, no one sells 93 or 94 octane. The "premium" fuel maxes at 90 and 91. When I run that....the bikes perform better and run cooler. I run between 4000-8000 feet depending on where I go and the climate varies from below freezing to well over 100 in the summer with minimal humidity.

Now my buddys Vulcan....now that its running.....was running 87 octane. It ran well. But its running better with the 89 octane. I will try a tank of 91 next to see if it runs better.

 

[thunder]

gen1 Vmax is designed to run on regular fuel. Higher octane gas burns slower and will not burn as efficiently actually losing power resulting in carbon build up. Higher compression motors require higher octane ratings or detonation will occur.
Sounds like your bike might need some seafoam to clean the carbs.

 

[Ted Drum]

What Octane gas are you guys running on your bikes? I’ve been running that Murphy Non-Ethanol gas because if the bike sets a bit I don’t want the Ethanol jacking up my carbs. But have noticed the bike runs crappy on it. Doesn’t like it. It’s only 87 Octane. I know the Max’s are 10.5:1 Compression. So just curious. May need to add some Octane booster to it. Anybody running 93 Octane? How does it run for ya? Also, I might add that my bike has Stage-7 Jet kit & full UFO Quadzilla Exhaust.

I have run cheap gas for 27 years not one problem
74 years old just bought my 2017 Vmax and put collector plates on my 1995 Vmax. The gen 2 is 10 times the gen 1 bike. Do not wait go for it, all bikes ride the same in the rain and need respect whether it is a NSU Prima scooter in 1958 or a Vmax gen2 today. The Gen 2 Vmax is best of all bikes I have ridden as they are bullet proof.
Some things to remember
1. Store it in a shed with a heater to raise the temperature 2 degrees above outside. No rust
2. Never work on it as you can only make it run poorly
3. Gel pack battery to start when engine is hot
4. Storage: take the battery cables off, do not charge the battery or use battery tenders. Come back in 6- 8 put a battery tender on for 2 days or until charged, install cables and drive away. A car battery charger will destroy the battery in 1 hour usually.
5. Both gen1 and gen 2 run just fine on cheap gas and there is no requirement for premium.
6. Fuel stabilizer must only be used as directed, excessive amounts will cause carb plugging problems.
7. The last 2 tanks of fuel should be something like Chevron Supreme Plus, 94 octane is ETHANOL FREE and available at all Chevron locations in British Columbia. It is the Ethanol and excessive amounts fuel stabilizer that cause of carb gum. Keep it full of gas in storage.
8. Read my posts on why gen1 have poor gas mileage and what must be checked before balancing the carbs of which you will probably not have to do.
9. Gen 1 over heating read my posts, briefly there is a little drain knob for the anti freeze lodged in the heads when your draining the cooling system.
You must read and understand how it works, if you do not have the knob in the OFF position of which is I believe the 2 o'clock position the cooling system will not work as designed. It operates like you have no thermostat or like your running it without anti freeze of which one would never do. The knob has a little set screw securing the knob in position. Loosen the screw and turn the knob a 1/4 to 1/2 turn to drain the heads do not try to remove as it is a like a ball valve with a rubber o-ring. Many people have changed the thermostat because the bike will not hold a some what constant temp when operating and it is the head drain knob in the wrong position. Leave the knob open and fill and run with new 50/50 anti freeze water mixture to ensure all air has been removed and then close.
10. If you change the thermostat make sure you have the proper Yamaha o-ring as metric and standard would not work and can cause case damage if too big. According to the book the thermostat needs to be placed with the small hole a certain direction. If you do not have a spring extension (like a speedometer cable) for your allen wrench get one or it will take about 3 hour fooling around with no room and an 1/8 of a turn at a time.
11. I used Lucas wet clutch standard oil for 25 years, not expensive $7 a quart

 

[02GF74]

If you do not have a spring extension (like a speedometer cable) for your allen wrench get one or it will take about 3 hour fooling around with no room and an 1/8 of a turn at a time.

 

[Parminio]

I have run cheap gas for 27 years not one problem

Probably because you've never had a high compression engine. Both the Gen 1 and Gen 2 Vmax run just fine on 87 octane gas because they have a 10 to 1 and 11 to one compression ratio respectively.

When you get to the R1 it's a different story. Yamaha recommends premium unleaded (Typically 93 to 95 octane) because of the 13 to 1 compression ratio. You CAN run regular unleaded in it but you run the risk of knocking and pinging and damaging the engine.

The higher compression needs the slower burn of higher octane to prevent damage to the engine itself and better overall performance.

 

[ouchez]

I have run the cheap gas in my 95 and 2017 Vmaxs since new, the last 2 fills before being put away for 6 months winter I fill it with Chevron Supreme that has no Ethanol (lawn mowers also) (ethyl alcohol) is a liquid alcohol typically made from fermented starches or sugars that come from corn or sometimes wheat. It can also come from grassy or woody crops (cellulose), or even garbage.

I use Stabil in a full tank, I run 89, run the Max for 10 minutes, shut it down, and then drain the carbs. I use a Battery Tender Jr and run it on the battery for 24 hours every week in winter, have the Gel cell battery. I have been doing this since 05 and all is well.

 

[Bullies74]

I use Star Brite with 87 octane at every fill up.

If my memory serves me well, fuel stabilizers are effective for up to (2) years or so.

Some years back, trying to save an opened bottle of Stabil, I added it to five gallons of fuel in my Harley.

Turned out, It was the wrong thing to do.

Fuel went bad and smelled awful.

 

[2017VMax]

Gas will explode under high pressure with no spark. Higher Octane gas can take more pressure before it explodes. When gas ignites before the spark, the piston gets pressure on it before top of the stroke. This causes heat and loss of power. The higher Octane gas doesn't explode any stronger than regular gas. High rpms with cause more pressure and can make lower Octane gas pre ignite. Unless you are really pushing rpms don't worry about it.

 

[Dorney]

Compression is not the only thing that warrants higher octane timing plays a big role in it to.

 

[Parminio]

Compression is not the only thing that warrants higher octane timing plays a big role in it to.

A roll? Possibly. A BIG roll? Not that I've ever seen unless, again, you're running high compression in the 12 - 13 to 1 and up category or you're running a super charger.

I've never seen any engine 11 to 1 or lower ever require high octane gas. Even Formula 1, the most advanced engines on earth, run regular unleaded gasoline of around 87 octane and they're pushing 13 to 1 compression. (But that is in large part to their advanced ignition systems that allow them to get away with that.)

 

[one2dmax]

A roll? Possibly. A BIG roll? Not that I've ever seen unless, again, you're running high compression in the 12 - 13 to 1 and up category or you're running a super charger.

I've never seen any engine 11 to 1 or lower ever require high octane gas. Even Formula 1, the most advanced engines on earth, run regular unleaded gasoline of around 87 octane and they're pushing 13 to 1 compression. (But that is in large part to their advanced ignition systems that allow them to get away with that.)

Try running 87 in an old 70 LS6 Chevelle with Iron heads and 11.3:1 factory compression. That will give you detonation except during winter months (at normal timing controlled by weights and advance mechanism set by springs).

 

[Parminio]

Try running 87 in an old 70 LS6 Chevelle with Iron heads and 11.3:1 factory compression. That will give you detonation except during winter months (at normal timing controlled by weights and advance mechanism set by springs).

That would fit under the "possibly" part of my post. Instances like that are not the norm, they're the exception.

 

[Tom8987]

What Octane gas are you guys running on your bikes? I’ve been running that Murphy Non-Ethanol gas because if the bike sets a bit I don’t want the Ethanol jacking up my carbs. But have noticed the bike runs crappy on it. Doesn’t like it. It’s only 87 Octane. I know the Max’s are 10.5:1 Compression. So just curious. May need to add some Octane booster to it. Anybody running 93 Octane? How does it run for ya? Also, I might add that my bike has Stage-7 Jet kit & full UFO Quadzilla Exhaust.

Very Informative

 

[Fire-medic]

Unless the compression ratio has been altered, the bike is designed to run on regular. Running premium on a stock bike is just draining your wallet faster. I run a Stage 7 and a UFO 4/1 w/a fabricated muffler canister. I use regular.