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Discussion Starter · #1 ·
Hello Group,

I have been trying to figure out what has been making my bike run poorly. When I first purchased it, it ran great, then two variables changed. I stopped putting in 91 octane as the owners manual calls for and started putting in 87 like many of you have recommended. On that same first tank of 87, I also added Sea Foam for the first time. From that point on, my bike didn’t run so great anymore. The problem it has is during acceleration, especially hard acceleration; it sputters and lags…not a smooth acceleration. This problem was the worst when I rode 40 miles with my girlfriend on the back recently.

Since the sea foam, I have gone through about 3 tanks of gas and the most recent fill up I tried the 91 octane again. During this mornings ride to work (25 miles), the bike ran better than ever. I can’t figure it out. Is it the gas? Do the carbs need to be rebuilt? Perhaps a temperature problem (this morning was cooler than most)? Does the Sea Foam make the bike run bad until it is all the way out of the system? I can’t figure it out. :confused:

As always, your wisdom is greatly appreciated. :notworthy

Adam
’85 VN700 :carryflag
 

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#1 have the air/fuel mix screws been messed with
#2 do u have any aftermarket pipes ect
#3 does ur area run oxygenated gas
#4 did it have any ethanol in the gas, many are going to 10% and mine ran crummy to, but the premium was still 100% gas
#5 The carbs may need it. Ole friend of mine had an 73 f250 and it stalled on anything but premium and we thought that the timing was off....turns out the carb was flooding the engine and for some reason premium reduced this.

Change ur plugs?!?.....the sea foam may have knocked some crud from the past lose and it covered ur plugs, i know it will coat o2 sensors with crud if its the first run
 

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Discussion Starter · #3 ·
Hizzo3 said:
#1 have the air/fuel mix screws been messed with
#2 do u have any aftermarket pipes ect
#3 does ur area run oxygenated gas
#4 did it have any ethanol in the gas, many are going to 10% and mine ran crummy to, but the premium was still 100% gas
#5 The carbs may need it. Ole friend of mine had an 73 f250 and it stalled on anything but premium and we thought that the timing was off....turns out the carb was flooding the engine and for some reason premium reduced this.

Change ur plugs?!?.....the sea foam may have knocked some crud from the past lose and it covered ur plugs, i know it will coat o2 sensors with crud if its the first run
#1 Not to my knowledge
#2 I don't have aftermarket pipes, however, I have wondered if the previous owner maybe did something to the stock pipes like this de-goating or whatever. The only reason I say that is because the bike is surprisingly loud for being stock.
#3 Yes
#4 No
#5 I will change the plugs, that should be cheap. Does my bike have oxygen sensors?

I should also mention that my bike is averaging 32 MPG every time I fill up. From what I understand, that is low.
 

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bcjoker04 said:
Hello Group,

I have been trying to figure out what has been making my bike run poorly. When I first purchased it, it ran great, then two variables changed. I stopped putting in 91 octane as the owners manual calls for and started putting in 87 like many of you have recommended. On that same first tank of 87, I also added Sea Foam for the first time. From that point on, my bike didn’t run so great anymore. The problem it has is during acceleration, especially hard acceleration; it sputters and lags…not a smooth acceleration. This problem was the worst when I rode 40 miles with my girlfriend on the back recently.

Since the sea foam, I have gone through about 3 tanks of gas and the most recent fill up I tried the 91 octane again. During this mornings ride to work (25 miles), the bike ran better than ever. I can’t figure it out. Is it the gas? Do the carbs need to be rebuilt? Perhaps a temperature problem (this morning was cooler than most)? Does the Sea Foam make the bike run bad until it is all the way out of the system? I can’t figure it out. :confused:

As always, your wisdom is greatly appreciated. :notworthy

Adam
’85 VN700 :carryflag
First off, the manual says to use a gas with at least 91 RESEARCH octane number. It also says to use a gas with a mininum rating of 87 antiknock index, which is an average of the research octane and motor octane numbers. Check out the pump and you'll see they use the antiknock index to rate the gas, so the 87 is the way to go.

Second, the Seafoam loosened up some gunk which is now stuck somewhere in your carbs. Try this; after the bike is running, turn off the gas and run it until it dies. Turn the gas back on, wait 3 or 4 minutes for the bowls to refill, start her up and repeat.

Third, the intake for the reserve pipe is probably gunked up too. Run a half tank of Seafoam rich gas(3 ounces per tankful) through it and be prepared for some sputtering and general crankiness until it cleans itself out.

If the easy tricks don't work, you may have to pull the carbs and do a thorough cleaning. I've never put more than 3 ounces of Seafoam in a full tank of gas and haven't had it run any different than without the Seafoam.

Non gas related issue: there's a breather hose tucked into a slot behind the right "ear". If it bottoms out or is unable to breath for whatever reason, it can cause problems at high rpm. If you check it out, cut it off at a 45 degree angle so it can't bottom out in the slot.
 

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there is an issue with bad gas mileage and poor running with oxygenated gas... also, sounds like u may need to do a carb cleaning...

bike doesnt have o2 sensors
 
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