 Posted: Sun Dec 26, 2021 12:42 am Subject: Pulled and cleaned carbs, now no start, sometimes backfires |
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| Hi yall, I got a 2006 ninja. I bought it brand new in 2006 off the show room floor and it has about 8,000 miles on it. I let it sit over the past summer and it would start up and idle for the most part, even drove it around the block, It would die at stop signs if i had the chock off or didnt play with the throttle to keep it running so i decided to pull the carbs and clean them. I have done this same job atleast 2 other times since i owned the bike with no issues at all. This time it wont even start when I was done. I have pulled the carbs off more than 10 times to check my work, check the float adjustments, even pulled a carb off another working ninja 250 with the exact same results so i know its not the carb. Battery its 100% and new. When i try to start it it will sometimes have a sigle "quick" pop like a gunshot with a flash out of the exhaust and then nothing, just turning over non-stop. It sounded like it backfire on the intake side at one point but im not sure. I have pulled the plugs, checked for spark, even took valve cover off and checked the valve adjustments. I adjusted the valves at around 4000 miles for general service and it ran fine after that. Im about to lose my mind. The only thing I did different was I put silicone grease, very lightly, on the carb boots to aid my in sliding them back on, if this were I messed up??? Im wondering it silcone grease getting sucked into the intake valve is enough to ruin it or make it not seal? I really appreciate any help in advanced. | |
| Posted: Sun Dec 26, 2021 9:24 am Subject: Fuel - or lack of it |
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How old is the gas? Gas with ethanol can go bad quickly. When cranking, back the choke off to about 3/4 if you hear any signs of life. It may be flooding. Sometimes opening the throttle slightly as you are cranking can help. Charge the battery between attempts. If the gas is fresh, open the floatbowl drains and see if you have fuel in the bowls. You could have an issue with the petcock not opening. It does take some amount of cranking to produce enough vacuum to open the petcock, and they can go bad. You can check that it flows by manually putting vacuum to the petcock with the fuel line disconnected and see if it flows fuel. I don't think the silicone would do anything unless there was a large amount between the plug and the boot, as it would act as an insulator. Also, over-oiling the air filter can cause problems. If you've serviced the filter lately, you may want to check or temporarily remove it. |
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| Posted: Sun Dec 26, 2021 2:44 pm Subject: reply |
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| Yeah, the gas was straight from the gas station pump and brand new, the air filter was new and same thing with or without filter in. The boots had wet gas in them after trying to start it and pulling the carb back off to check it again. | |
| Posted: Mon Dec 27, 2021 9:24 am Subject: Fuel - too much? |
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Then there is an issue with the carbs, or it was flooded. |
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| Posted: Mon Jan 03, 2022 8:21 pm Subject: Check the valve adjustment and cam timing. |
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If it's not the carbs, then it's compression/valve timing or spark. If you checked the plugs, it is unlikely that is the issue. Is it possible that you have the cams out of time? Check the cam timing, I know I've put mine together with one of the cams off by a tooth. Never got so far as to try to start it that way, but I've had to remove and re-time the cams more than once. Rereading your post, it could also be a vacuum leak at the carb boots. This can be checked by giving it a (small) shot of starting fluid when starting the engine. If it runs on starting fluid, you're not getting fuel. I also notice no one has mentioned making sure the pilot jets are clean/open. |
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