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Any help with this would be much appreciated for this aspiring DYI person.

Several months ago my 99' SV started running rich for unknown reasons. I did not do any modifications to the bike. Please don't harass me too much about procrastination, kicking myself enough on it.

Symptoms:
-smells like gas in the airbox
-some visible smoke during initial startup and exhaust reeks of gas, after completely warmed up smoke is not noticible and doesn't smell as bad.
-after warm up, I need to rev to about 3-4k to keep it from bogging down for the first atempt to get moving
-the top of the intake valves are well coated in carbon-oily looking.
-spark plugs were blackish but 2 friends said it looked fairly normal wear

I put in a new set of spark plugs a week ago and the engine was sounding crisp and none of the above symptoms occurred and felt overall better performance, for about 2 hours.

Today I decided to get down to the problem and pulled the carbs out, everything is stock, the needles/jets seem to be fine, the A/F was 2.5 turns out as stock. A couple SVers had problems with the vacuum hose, but it appears to be fine. I don't have the tool for measuring fule level in the bowls, is it that important to check?
 

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Did you ever get a response to this post? My bike is doing the same thing, however my carbs were jetted by the previous owner. I've had the bike for 3 years now and it just started acting up. I attempted to diagnose the problem myself, but gave up. I took the bike to my local Suzuki dealer. They charged me 70 bucks to replace my spark plugs. The bike ran good for about 2 rides but now its back to sputtering at idle. The dealer said if its not the plugs the would recommend re-jetting the carbs. This make sense to anyone? I may attempt to do this myself since the want to charge an arm and a leg for them to do this. Any suggestions would be great before I start tearing my carbs apart.

Thanks
Kev
 

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Sudden rich running is not jets or plugs that were changed recently. The two most common causes are a bit of trash in one or both needles and seats causing too much gas to get in the carburetor bowls or a hanging-up choke mechanism (actually it's an enricher circuit, not a choke).

Jets don't suddenly go bad and need redoing. The only thing that happens to jets is they clog and you run very lean or not at all. Plug fouling can cause your exhaust to smell very rich, but you would either have a dead cylinder or one that misfires almost every time. The airbox will always smell like gas, that's normal.

What both of you report, good running with fresh plugs, deteriorating rapidly, is typical of a too rich condition. kev7van has a rejetted bike. I'd go back stock and see what happens. Meinas_2, I'd check the choke cable routing and the mechanism at the carbs. If that looks normal then I'd disassemble the carbs and blow everything out with compressed air (remember your eye protection).
 

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Yea I would probably go back to stock jetting, adjust AF screw, fresh plugs and diagnose from there. Run it for maybe few days and check plugs see where you are at. I had an issue for many months where it smelled rich and kinda sputtered at idle and I could not get the jetting right. Backed off the AF screw and now its fine.

Defiantly a guessing game for the average Joe like myself.

Is the air filter clean? I guess that the airfilter could hypothetically restrict air flow to the carbs causing too much fuel in the mixture as well.
 

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Air filter is a K&N and I did clean it.... Heck I dumped all the gas out and filled it up with new higher octain fuel to rule that out. You guys mentioned taking it back to stock. What if I'm running with a yoshi pipe, shouldn't it be jetted to match? One thing I didn't mention in my last post is that the front plug is running lean and the back is running rich. I've sync'd the carbs so I know thats correct. I just cant get the air to fuel mixture correct. I read another post where someone said it could have been caused by the coils. Could it be that? I was going to check that something this week b4 tearing my carbs apart.

Thanks :BangHead:

Kevin
 
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