A buddy of mine just bought a new dirt bike, an 02 exc. thing is loaded, has a steering damper, boyesen reeds, full fmf system, aftermarket seat, even a polished swing arm. things snorts, blows my old kdx 200 out of the water. anyhoo, the first day he road it, it was stalling on him quite a bit, gave him lots of trouble, i just told him he needed to get used to a 2 stroke and use the clutch more, keep it in the rpm range it likes, when i road it it died on me as i was coasting down a hill, but otherwise i did ten miles on it no problem. On day 2, he's riding up a dirt road above my house to get to the trails ~40 mph, he cracks the throttle just for kicks, and 2 seconds later the things seizes. Now, the radiator was cool, (ambient air temp was about 40 degrees the bike had done about 5 miles that day), but we couldn't kick it for 30 or so seconds. we pray its vapor lock. now when the bike kicks over, seems to have pretty good compression but wont fire. we pulled the plug, it was horrible, and have ordered several new ones. we also pulled the carb, and reeds (this is how i found out about the sweet reeds) checked everything on the intake end, all is well. the reeds are in tip top shape, the carb too, we went through the carb anyway just to do so. So then we tried to fire the bike with some starting fluid at no avail, not even a pop. So it LOOKS like this thing seized and we'll need a new nikasol coating (great) and a new piston (woohoo). When trying to figure why this locked, we looked at every angle, the gas was mixed good (40:1), the intake and exhaust is good, air filter was recently cleaned, i mean it seemingly had no motivation to die. Now, my prayer is some sorta freak vapor lock, and that everything is fine, and it needs a new spark plug. But the reality seems that the fuel/air mixture had to be too lean to cause that much heat that quick to seize the piston. we live at 7k feet here, and with the full fmf pipe, i need a starting point to rejet this thing to make sure we got a good mixture. i did pill the main and pilot jets during the carb clean, but didn't even think to glance at the size of them. any jetting help, and opinions of what happened and how to preven it in the future would be MUCH appreciated. that's a capitol much. that means i might buy you some beer. if you like utah beer.
2003 200 exc seized.
Started by the, May 11 2009 10:53 PM
2 replies to this topic
Posted 11 May 2009 - 10:53 PM
A buddy of mine just bought a new dirt bike, an 02 exc. thing is loaded, has a steering damper, boyesen reeds, full fmf system, aftermarket seat, even a polished swing arm. things snorts, blows my old kdx 200 out of the water. anyhoo, the first day he road it, it was stalling on him quite a bit, gave him lots of trouble, i just told him he needed to get used to a 2 stroke and use the clutch more, keep it in the rpm range it likes, when i road it it died on me as i was coasting down a hill, but otherwise i did ten miles on it no problem. On day 2, he's riding up a dirt road above my house to get to the trails ~40 mph, he cracks the throttle just for kicks, and 2 seconds later the things seizes. Now, the radiator was cool, (ambient air temp was about 40 degrees the bike had done about 5 miles that day), but we couldn't kick it for 30 or so seconds. we pray its vapor lock. now when the bike kicks over, seems to have pretty good compression but wont fire. we pulled the plug, it was horrible, and have ordered several new ones. we also pulled the carb, and reeds (this is how i found out about the sweet reeds) checked everything on the intake end, all is well. the reeds are in tip top shape, the carb too, we went through the carb anyway just to do so. So then we tried to fire the bike with some starting fluid at no avail, not even a pop. So it LOOKS like this thing seized and we'll need a new nikasol coating (great) and a new piston (woohoo). When trying to figure why this locked, we looked at every angle, the gas was mixed good (40:1), the intake and exhaust is good, air filter was recently cleaned, i mean it seemingly had no motivation to die. Now, my prayer is some sorta freak vapor lock, and that everything is fine, and it needs a new spark plug. But the reality seems that the fuel/air mixture had to be too lean to cause that much heat that quick to seize the piston. we live at 7k feet here, and with the full fmf pipe, i need a starting point to rejet this thing to make sure we got a good mixture. i did pill the main and pilot jets during the carb clean, but didn't even think to glance at the size of them. any jetting help, and opinions of what happened and how to preven it in the future would be MUCH appreciated. that's a capitol much. that means i might buy you some beer. if you like utah beer.
Posted 12 May 2009 - 12:30 PM
well we tore into the head today and the piston and cylinder is completely toast, i need some place to send this to get a new nikasil plating in it, any recommendations for a good compnay that does nikasil replating?
Posted 13 May 2009 - 09:12 PM
nothing on the replate.
Jetting for 7k' should be about a 175-178 main, 40pilot, and a different needle than stock. JD kit is magic in the 02. Others are the Sudco's, DDK, DCJ, CEK, and othrs in tis range. The stock needle is crap for the bike and it wont run to its potential til its changed.
Jetting for 7k' should be about a 175-178 main, 40pilot, and a different needle than stock. JD kit is magic in the 02. Others are the Sudco's, DDK, DCJ, CEK, and othrs in tis range. The stock needle is crap for the bike and it wont run to its potential til its changed.
