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Discussion Starter · #1 ·
Hello all, I'm fairly new to this forum but I've got an issue on my 96 M900 and have seen some very knowledgeable people posting on here. I did a factory pro jet kit and emulsion tubes on my carbs about 4 months ago and it started running richin both cylinders. After about every leaning adjustment I think I can make (and finally figuring out I was using the wrong plugs), I've got it running pretty good now but it still stuttters a little in 2nd and 3rd when I go to get on it (especially when cold). When I pull the plugs one looks pretty good and the other is always black, but not oily (and I'm not losing oil). Adjustments to the carb are as follows: I dropped the needle to the 2nd lowest notch. I have adjusted the floats to about 15mm. I have the smallest main jet installed but have tried them all. I have a 42.5 pilot jet installed but have tried a smaller one also. I also tried swapping the coils thinking maybe it was a weak spark but that did not do anything either. I have also synced the carbs. I don't know where else to go. I think it has to be in the carb somewhere but I don't know what else to adjust. Any ideas would be greatly aprreciated. Thanks,
 

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What other mods have you got? Particularly air filter/air box and exhaust. I suspect the recommended settings in the FactoryPro jetkit will be quite a bit too rich for a bike with stock airbox and exhaust. If the 900 kit is anything like the 750 kit I got from them, the needles are much thinner and more tapered than the stock needles so with stock inlet and exhausts you'd probably need to go even smaller than stock on the main jets to keep it from running rich. I ended up with the stock 132.5 mains (which are a size smaller than the smallest of the three main jet choices in the 750 kit) with the FactoryPro needles and springs, and I've got a chopped airbox and unbaffled Staintune slipons (on the stock headers).

That 15mm float height won't be helping any, I'm pretty sure 14mm is the spec for that - have you tried dropping that back down?

big
 

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Very good description of your problem & good faultfonding too!
And welcome to the board.

Do you have aftermarket slipons?
Do you have open air filter, meaning opened airbox lid or pod filters?
Do you know if your jet kit is Stage 1, 2 or what?
What are your main jets now?
I`m also pretty sure 14 mm is the correct float height.
 

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Check the vent tubes to the diaphragm housings. If one is kinked/pinched the slide won't lift and it will run rich.
 

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Discussion Starter · #5 ·
Thanks for the advice guys. I have after market Forza pipes and its a stock airbox lid but the person I bought it from had already cut 4 pretty good size holes in it. To be honest it's been a few months since I last changed anything and I don't remember what the last main jets I put in it were (I've changed them so many times) but they were the smallest ones I had. Maybe I'll try to see if the dealer got some smaller ones. and I'll check those lines but I don't think they are kinked. Thanks again.
 
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