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Harley Davidson
Introduction
Harley Davidson slots are what are known in the industry as "variable-state" games. That means the expected return on any given spin is variable, depending on value previous players have banked into the game or taken out. To be specific, there is a free spin bonus, where there are incrementing meters for the number of free spins. If the meters are high enough, the game offers an expected return over 100%.
A good and easy advantage play is to prowl slot machines for Harley Davidsons and similar games, looking for machines abandoned in a positive state. After finding one, swoop in like a vulture and play it until you reap the value, leaving the machine in a negative state for the next player.
Rules
The rules for Harley Davidson are rather complicated and vague. It is beyond the scope of this page to explain them all. There are three ways the player can win, as follows. The approximate return percentage of each feature is shown in parenthesis.
- Line pays (73.5%)
- Wheel bonus (6.7%)
- Free spin bonuses (5.7% on average)
I won't get into the line pays and wheel spin bonus because the return from the sum of the two is constant. What the skilled player should focus on are the free spin bonuses.
There are scatter symbols on reels 1 and 3. On reel 5 are bonus symbols. The game has a "symbol replacement" feature, where special symbols, namely the wild, scatter, and bonus symbols, randomly replace other line pay symbols. The more the player bets, the more scatters and bonus symbols will appear.
There are four types of bonus symbols:
- Wheel bonus
- Mega RPM free games
- Maxi RPM free games
- Mini RPM free games
If the player gets 0 or 1 scatter and any of the free games bonus symbols, then one additional free game shall be added to the meter of the specific free game bonus symbol. For example, if the Maxi free spin bonus has 20 free spins in the meter and the next spin results in a Maxi free spin symbol on reel 5 (with less than two scatters on reels 1 and 3), then the Maxi free spin meter shall be incremented by one, to 21.
The three free spin banks are different for every number of credits the player may bet, so check all if them if checking machines for positive value.
If the player gets a scatter on reels 1 and 3 as well as any bonus symbol on reel 5, then the player shall play the bonus associated with the bonus symbol on reel 5.
The Mini free spin bonus meter shall reset after a bonus at 7 free spins. All free spins in the Mini free spin bonus have a 1x multiplier. Likewise, the Maxi free spin bonus resets at 8 free spins and has a 2x multiplier. Finally, the Mega free spin bonus resets at 10 free spins and has a 3x multiplier.
Free spins use separate reel stripping, with no scatters or bonus symbols. I believe the expected return of a free spin, before applying any multiplier, to be 81% to 85% of the initiating bet.
There are more Mini free spin bonus symbols than Maxis and more Maxis than Megas. Thus, the Mini will be hit the most frequently and the Mega the least.
The machine pictured in this article from the Four Queens in Las Vegas had a maximum wheel win of $10,000. Some other Harley Davidson machines have a progressive jackpot slice on the wheel. If that is the case, the expected value at any given time will also be a function of that progressive. How specifically the jackpot amount affects the value, I'm afraid I don't know.
Strategy
The big question is what is the expected return of the game according to the number of free spins in the three free spin meters. Let Mini, Maxi, and Mega be the number of free spins in each meter. Here is my answer to that question:
Return = 0.8018 + 0.003858×Mini + 0.002518×Maxi + 0.000948× Mega.
Let's take a look at the image above, as an example. It shows Mini = 23, Maxi = 30, and Mega = 97. Thus the return is 0.8018 + 0.003858×23 + 0.002518×30 + 0.000948×97 = 1.05803. In other words, the game has a 5.8% player advantage on the next spin. The value is certainly more, because the player can keep playing it in the positive state until it is no longer positive.
Another formula that works to estimate the expected value at any given state is:
Expected value = 80.18% + Mini/259 + Maxi/397 + Mega/1055.
For example, in the picture above, the return would be 80.18% + 23/259 + 30/397 + 97/1055 = 105.8%.
Rules Screens
Following are the rule screens. Click on any image for a larger version.
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Internal Links
Following are analysis of similar variable-state slot machines.
Acknowledgements
I would like to thank anonymous for sharing with me information about this game. Some of the analysis is above is based on his work. While it looks reasonable to me, I can't vouch for it 100%. Therefore, I would take the information on this page with a grain of salt.
External Links
VULTERING HARLEY DAVIDSON SLOTS — Discussion in my forum at Wizard of Vegas.