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625 engine problems

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I am having problems with my smc. I had to shelter because of the hurricane (I'm stationed in Mississippi) but I managed to get the bike in my house(got lucky no damage). When I got home I tried to go for a ride and it started chugging and died like I had ran out of gas. I thought maybe I had just gotten a bad tank of gas drained it and refilled it again and it seemed to run fine for about a half hour than it started again. To get home I had to pull the choke out to rev it high enough to keep it going. It only seems to happen once the bike gets warmed up. It runs when I'm on the gas but as soon as I shut the throttle it dies. I did my valves about a month ago and it's been running perfect until now. Any help would be great, I need to get to work on monday.

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Is your bike still stock? Have you taken any of the emissions equipment off? It sounds to me like your bike has stock jetting with a 165 main which is way too lean and is probably burning up your motor. You need to install a 175 right away. What about the throttle stop in the carb? Did you remove that?

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Bike is stock however the dealer took the carb slide off and I cut the screen from the end of the exhaust pipe. Can I get just a 175 main or do I need to order a whole jet kit? It doesn't seem like it runs to hot the fan hardly ever kicks on usually just when I'm stuck in traffic, but my headers are blued pretty good. If it is the jetting why would it start messing up all of a sudden, wouldn't run like crap from the start?

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Yeah just buy a 175 and stick it in there. It sounds like the bike runs ok until it heats up and then starves for fuel. I would change it immediately because if it keeps shutting off on you you're lucky the motor hasn't froze up yet.

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When you say that you had to pull the choke out to keep it running, are you sure it was the black choke knob or the red hot start knob?

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Pulling the choke (black knob) it starts reving really high but stays running, the exhaust does alot of little back fires just keeps poping. Pulling the hot start (red knob) it chokes right out and dies. I've got almost 2,000 miles on it so far shouldn't I have had problems before this? I'm gonna order a 175 tonight and through it in this weekend.

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Check your pilot jet. It may be clogged. My 525 had a clogged pilot when I bought it. Wouldn't run without the choke. You should be able to see through it along the length of the jet. New ones are 5 bucks, so if you don't have something small enough to clean out the jet, just buy a new one. Also, water can clog the jet!

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The main jet has little to no effect on idle. As stated previously your pilot jet may be clogged. Another thing you might want to check for is an intake vacuum leak, check the hose from the intake to the fuel tank peacock and the SAS hose to the intake if the SAS is still installed if it is not ensure that where the SAS hose was connected to the intake is sealed. But from what you have stated I think it is more likely that you could have some water in your fuel. Are you sure you emptied all the fuel from the tank and carb bowl? Was the fuel that you put in after draining the tank from the same source as the original fuel?

You should probably install a larger main but I doubt that your main jet size is the cause of your idle trouble.

Good Luck

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