frogonwheels Posted November 19, 2012 Report Share Posted November 19, 2012 Hello guys, I bought a few weeks ago a Kawasaki KT250 from 1976 with 75 miles on it ! While almost new, there are of course a few issues mainly due to not being used. The bike now runs very good. There was a dead spot right over idle when cruising in low gear and opening the throttle. A little delay of a second or so. I opened the carb, reset the needle to factory setting, installed a new float valve and a new bowl gasket. That did it as far as the one second hiccup. BUT, just as when I bought it, as the bike seats on its sidestand overnight, gas comes sipping out between the bowl and the carb body itself. As I put some premixed gas in the tank as I was sorting out the engine and wanted to be sure the oil pump worked, the gas is for now a bit blueish from the 2 stroke oil. It is easy to spot the gas right at the seam above the bowl and there is always a small puddle underneath the carb on the engine. Nothing when the engine is running. As I thought the petcock might not shut off properly, it was anyway a bit hard to rotate, so I installed a brand new one. Of course, at this point, I am out of ideas of what might be the issue here. Any suggestions here fellows ? Thanks for your help. Terry Quote Link to comment Share on other sites More sharing options...
b40rt Posted November 19, 2012 Report Share Posted November 19, 2012 Missing gasket ? Quote Link to comment Share on other sites More sharing options...
twinshockdude Posted November 19, 2012 Report Share Posted November 19, 2012 the float bowl has probably been distorted by over tightening,get some fine abrasive paper on a FLAT surface and lap the gasket face of the float bowl,use a circular motion untill the whole face has cleaned up. Quote Link to comment Share on other sites More sharing options...
frogonwheels Posted November 19, 2012 Author Report Share Posted November 19, 2012 the float bowl has probably been distorted by over tightening,get some fine abrasive paper on a FLAT surface and lap the gasket face of the float bowl,use a circular motion untill the whole face has cleaned up. That is a very good possibility. The problem with this Mikuni carb, the bowl gasket actually seats inside the casing as there is a lip on the outside of the top edge. Impossible to flatten the contact face ! Maybe it is time to get a new carb after 36 years ? Quote Link to comment Share on other sites More sharing options...
tayld Posted November 20, 2012 Report Share Posted November 20, 2012 Hi there, Do you get the same seepage if the bike is stored overnight on a workshop stand which keeps the bike level? Unless the bike is leaning over at very steep angle on its stand to cause the leak it could be worth checking the float height. Check the manual for the correct float height and the method of checking it. Assuming "new float valve" means the float needle plus perhaps its seat checking the existing float (if it is of hollow construction) for leaks might be worth a try. Remove the float from the carb and immerse the float fully and quickly into hot water, watch for a small stream of air bubbles to indicate a leak. Quote Link to comment Share on other sites More sharing options...
jon v8 Posted November 20, 2012 Report Share Posted November 20, 2012 I dont know what layout your bike has,but I had a similar problem on a TDR250 Yamaha which was caused by the o rings which sealed the float needle seat into the carb body shrinking.I think this type of float seat is only on later carbs,does your float seat screw into the carb body ? Quote Link to comment Share on other sites More sharing options...
dixie Posted November 21, 2012 Report Share Posted November 21, 2012 A tiny amount of Vasaline around the O ring will help it seal, and dont over tighten the screws, over tightenihg is as bad as leaving them loose. Quote Link to comment Share on other sites More sharing options...
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