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Discussion Starter · #1 ·
Hi All,

I think I may have two different problems but here goes...

Problem # 1...

For about the last four tanks of gas instead of making it to 112 miles before the FUEL light comes on it has been making it to 56, 77, and 89 miles and then the light comes on.

The 56 miles I was able to reproduce and it ended up being a fuel leak, the 77 and 89 were from the last two fill ups, I have two theories on this...

1 - I have barely ridden it at all this spring/summer due to the un-ending rain here and the gas is just simply evaporating out of the tank through the vents in the filler cap.

2 - I have a carb. problem and it is dumping way too much gas in cylinders.

Problem # 2...

This problem has slowly been getting worse, as time has gone by I have had to leave the choke on longer and longer or the engine stalls when I come to a stop, I have tried pushing the choke all the way off and then turned the idle knob so that the engine is running at 1,100 rpms.

The next time I stopped the idle dropped to about 800 stumbled around then slowly made its way back up to 1,100, then the next time I stopped it stayed at 1,100 for a moment then instantly stalled but then fired right back up when I tried to start it.

I have a feeling that both problems are related but wanted a few opinions before I take the time to pull the carbs out, when I am not at an idle the motorcycle runs fine and has a lot of power and has no trouble getting me from point A to point B.
 

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Discussion Starter · #2 ·
Well, it seems that these two were related and are apparently taking care of themselves, once the engine is in the HOT zone on the temp gauge I can shut the choke all the way off and the engine doesn't stall when I come to a stop.

This seemed to occur during the last half of the last tank of gas it had in it, and it made it to 100 miles before the FUEL warning light came on (annoyingly right as I was on the on-ramp to the freeway). At this rate if I can make it through another tank of gas and being able to shut the choke all the way off it should make it to 112 miles like it should be before the FUEL warning light comes on.

About the only explanation I can come up with is that the carbs just did not like sitting all winter and something went wrong inside of them that constant riding finally cleared up, due to the horrid weather I was only able to ride it once a week (if that) until our summer weather finally arrived a few weeks ago.

Another odd thing is that this is the first year that I have been able to run regular (87) in it instead of supreme (92) without the engine sputtering and bucking on me, which is a nice surprize considering the current cost of gasoline.
 

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I have an 84' 700 as well, I get a bit better that 50 mpg. My fuel light comes on around 145 miles. I run 87 octane in it and it is all stock. I do encounter strange idling sometimes, rpm's drop if I shake the bike or tilt t the right, rpm's rise if I tile left. Have not been able to diagnose the issue but it is not too annoying.

Do you have any aftermarket intake or exhaust parts? Have you re-jetted the carbs? If not then I would recommend disassembling the carbs for a good cleaning and inspection since it is not too much of a pain to do. I would check your spark plugs and see if the need replacement and there color/condition. That can tell you what is going on with your combustion. Check to see if you have a nice blue arch when the plugs fire instead of a yellow or orange color. Air filter may be dirty. Check your oil level. I would also download the manuel from the general discussion portion if you have not already, it has good info and troubleshooting in it.

Good luck

 

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Discussion Starter · #4 ·
I have an 84' 700 as well, I get a bit better that 50 mpg. My fuel light comes on around 145 miles. I run 87 octane in it and it is all stock. I do encounter strange idling sometimes, rpm's drop if I shake the bike or tilt t the right, rpm's rise if I tile left. Have not been able to diagnose the issue but it is not too annoying.

Do you have any aftermarket intake or exhaust parts? Have you re-jetted the carbs? If not then I would recommend disassembling the carbs for a good cleaning and inspection since it is not too much of a pain to do. I would check your spark plugs and see if the need replacement and there color/condition. That can tell you what is going on with your combustion. Check to see if you have a nice blue arch when the plugs fire instead of a yellow or orange color. Air filter may be dirty. Check your oil level. I would also download the manuel from the general discussion portion if you have not already, it has good info and troubleshooting in it.

Good luck

The ignition system is not the problem, this thing has so much power when it takes off when I was riding it yesterday I let off the clutch and gave it gas too quickly it jerked so hard that it actually made my neck hurt.

Everything from the air cleaner all the way to the end of the exhaust pipes is stock, this thing doesn't need any more power than it already has so I have just left everything alone.

From day one when I bought it roughly five years ago the FUEL light always came on right around 123 miles, after Oregon mandated 10% ethanol in gasoline it dropped and always came on at 112 miles, so I just figured this is how it runs and have never bothered to do anything about it since it gets 51 mpg in the city.

My idle has strange rises and falls also, ethanol has a lower energy content than straight gasoline does, my guess is that when the idle drops it is getting a higher ratio of ethanol to gas then it levels out and the idle goes back up. About the only way of testing this theory (in Oregon) that I can think of is completely draining the fuel system and running 100 octane aviation fuel in it (which contains 0% ethanol) and then see if the idle problem goes away, not really a big issue anyway since the engine says running despite the rises and falls.

For now I'm just going leave everything alone and burn through this next tank of gas and see what happens, the weather is going to be awesome here next week so I'm going to take it to work everyday and then next weekend it is going on 3 hour round trip.
 

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Hmmmm... I'm getting 65 mpg with mine... have yet to see the fuel light. I'm wondering, have you checked your plugs to determine if you're running too rich? How's your air filter? Fuel filters? Maybe run some Seafoam through your tanks? You might try running blue avgas through it, I've played around with that a bit here and there over the years... avgas in motards, mogas in planes... But I've ran regular mogas in my ride for the last year, ethanol or not, with no significant effects.
 

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Discussion Starter · #6 ·
Hmmmm... I'm getting 65 mpg with mine... have yet to see the fuel light. I'm wondering, have you checked your plugs to determine if you're running too rich? How's your air filter? Fuel filters? Maybe run some Seafoam through your tanks? You might try running blue avgas through it, I've played around with that a bit here and there over the years... avgas in motards, mogas in planes... But I've ran regular mogas in my ride for the last year, ethanol or not, with no significant effects.
Do you get 65 city, or 65 highway? Mine gets 51 city, 61 interrupted highways (go through a small town every 10 miles or so), and 66 on open highways (freeway).
 
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