rockout12001 Posted March 7, 2009 Share Posted March 7, 2009 i just rebuilt the engine and now need to get the carb tuned in. it is a 78 yz80 with a 73 gt80 engine. it ran good before, but that was with really low compression. now with it rebuilt, it doesn't want to idle without me "choking" it with a finger over the intake. to me it sounds like an air leak. i have new intake gaskets and did find a leak on the gasket inside the carb where it "pinches" around the intake. after sealing it off, it seems a little better. i have tried moving the needle adjustment, but it is still very sluggish when opening the throttle and will not idle down. any suggestions? the carb has been completely gone through, so i know it isn't an internal problem. Link to comment Share on other sites More sharing options...
rockout12001 Posted March 14, 2009 Author Share Posted March 14, 2009 anyone? please? help? replaced carb to intake "gasket" , tried moving needle adjustment, still will not idle at all. if i cover the carb with my fingers it will idle down, but as soon as i remove them, it "races" up and will not idle down. sprayed carb spray all around the intake and no change, but if i spray into the carb, it does idle down. PLEASE, can someone help me out. my kid is dieing to ride it. Link to comment Share on other sites More sharing options...
Twin Shock Posted March 14, 2009 Share Posted March 14, 2009 Tell me what you did to the engine. Link to comment Share on other sites More sharing options...
rockout12001 Posted March 15, 2009 Author Share Posted March 15, 2009 just new top end. piston, pin, bearing, gaskets. bored to 20 over. took carb apart. cleaned out all jets. checked float, etc. all seemed ok, just junk in the bottom of the bowl. slide is nice and free. i thought it was a vacuum leak. when rebuilding, installed new intake gaskets then. made sure bolts were nice a tight. sprayed carb spray all over the place. only place engine changes is when sprayed directly into carb. Link to comment Share on other sites More sharing options...
Twin Shock Posted March 15, 2009 Share Posted March 15, 2009 just new top end. piston, pin, bearing, gaskets. bored to 20 over. took carb apart. cleaned out all jets. checked float, etc. all seemed ok, just junk in the bottom of the bowl. slide is nice and free. i thought it was a vacuum leak. when rebuilding, installed new intake gaskets then. made sure bolts were nice a tight. sprayed carb spray all over the place. only place engine changes is when sprayed directly into carb. It I were working on this bike I would do a leakdown test to determine is there is an airleak in the engine. Then I would look real hard at the carburator again. If you had "junk" in the bottom of the bowl you have "junk" through out the carburator. I am really leaning towards carb issues here with your problems. You can soak you carb in Berrymans and it does a great job at dislodging particles in passages that you can't see. Link to comment Share on other sites More sharing options...
rockout12001 Posted March 15, 2009 Author Share Posted March 15, 2009 i have taken the carb apart a few times thinking the same exact thing. it has soaked overnight, torch tip cleaned all ports, sprayed all ports. jets clean as could be. i am at my wits end with this thing. Link to comment Share on other sites More sharing options...
Twin Shock Posted March 15, 2009 Share Posted March 15, 2009 Looking at your profile you have a couple of GT 80's. Why not try one of those carbs to help you isolate the problem. Link to comment Share on other sites More sharing options...
rockout12001 Posted March 16, 2009 Author Share Posted March 16, 2009 wish i could, but no carbs on them. in fact, i just sold both of them after taking all of the parts off that i thought i could use. just didn't have the room in the garage and didn't want them outside where someone could take them. Link to comment Share on other sites More sharing options...
rockout12001 Posted March 17, 2009 Author Share Posted March 17, 2009 figured it out. crank seal blew out sucking air through there. Link to comment Share on other sites More sharing options...
Recommended Posts