Was too lean-now too rich?

Keith1962

Keith1962

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Joined
Oct 16, 2012
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74
Location
Camillus NY
I had a bad flat spot/bog at 1/4 - 1/2 throttle on my 2001 Venture 600. I lifted the needles 1 notch. Much better throttle response over 1/3 throttle, but seems really fat at low speeds. Burbles a lot. Just not right. I was thinking I might try moving one of the two washers from under the circlip to above the circlip. What do you guys think?
 
The washers are your "in between" adjustment, so go ahead and try it...
Is your sled completely stock??? If so, there is a couple of ways to maybe help you rid the burble that you are talking about.
There is a modification in the Tech section called the reed stopper notch modification, this can be done, or, there is a reed block spacer, which is another way of opening(spacing) the intake transfer port that help eliminate that burble.
 
Is this sled new to you?? if so, I would clean the carbs(fuel passages) to ensure that they are clean and don't have any ethanol gum balls floating around in the bowls and hindering fuel flow through the jets which could cost BIG $$$ if you burn the motor down. Plus you will have a heck of a time tuning as it will be rich then lean(and so on) and it will drive you NUTS.

SO #1 - Clean the carbs(check the jetting).

#2 - either do the reed stopper mod or install reed spacers (can be found on ebay or Rich motorsports [sponsor on this site], Bender racing, etc).
The reed stopper is pretty much a free mod but I like my spacers on my sled better as I know the port is open, and the notch or spacer is known to reduce the burble significantly.
 
Thanks for the reply. Yes the sled is new to me. Before I ever rode it I pulled the carbs and had good friend who has been a bike/sled/ATV mechanic for decades go thru them. I drained the tank and refilled with fresh fuel. We ran it one weekend, then lost our snow here, so I was unable to ride it again until now. I did have on over temp light coming on, but I found that I had a minor coolant leak which I repaired, and, after purging the air, I have no signs of overheating. The thing that was bugging me was "dead" spot- weird (to me) burbling. Seemed a little lean to me. I raised the needles one place up, but now it burbles badly until roughly 1/3- 1/2 throttle. Also, the guys behind me say it smells rich. So I was thinking of using the washers to lower the needle a bit, or put it back the way it was. I also went back thru the carbs to make sure they are clean, which they are. I also refilled the fuel tank with 91 octane fuel vs the 87 octane I was using. The 91 octane is non-ethanol. I not sure if the different fuel is making any difference. I'll research the mod you suggested too.
Maybe it was rich to begin with and I made it worse?
 
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possibly was rich and you made it worse... Here in Mi I thought that the higher octane fuels were non - ethanol, but I found out that ALL of the fuels here in Michigan (except for race gas) contain 10-12% ethanol. I went to a local marine dealer and acquired a vial that you fill to a certain line with water and to another with you favorite blend of fuel and shake vigorously for like 10 seconds, then you let the vial sit and wait for the fuel/water mixture to seperate(took me 20-30 minutes) so that you can read the gauge on the vial that will tell you basically how wet the fuel is... The water you added hydroscopically removes the water/alcohol/methanol from the petroleum blend that was blended at the refinery. You may be surprised that the fuel you purchase may not be as advertised... IMHO the fuel companies are using all kinds of cheep fillers to stretch the petroleum as far as they can to gain maximum amount of profits. my $.02
 
Was the jetting in the carbs stock? If so, Yamaha made there jetting on the rich side to begin with, so richening the needle, would make it worse. I recommend the reed spacers, they help clean up the burble. They are fairly cheap and easy to install.
 
The 91 Octane here says non-ethanol on the pump. And they advertise it as such, good for your toys......... If I do the reed stopper notch mod, which should be pretty easy, do I need to any jetting changes from stock? As far as I know, it has stock jetting. An elderly man owned it before me, I doubt he changed anything. Now it's me and my 11 year old daughter. When she graduates to her own sled, then I can get something sportier.....
 
Thanks for the input guys. I took the carbs back off. I gonna try lowering the needles one clip and moving one washer. Looks like I went the wrong way. My plugs looked pretty black before I raised the needles. I should've know better.
 
Tried that. Needles with the clip in the 3rd slot, and one washer under the clip. Much better. The plugs look good. I guess I was too rich rather than too lean to begin with.
 
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