I have an issue. I've had my 01 426 now since March.
First, my riding history: I have attended 2 hare scrambles and have raced on an outdoor motocross track 4 times (2 motos per day, 5 laps per moto, plus a 12 min 'practice session' once per day). I have ridden the bike maybe 15 hours of actual 'play riding' at an ORV park in the local area. The oil was changed the day I picked it up, and every 2 weeks since (unless I didn't ride AT ALL during the 2 weeks...then I'd put it off for 2 weeks...if I even rode once during the 2 weeks, though..I change the oil and filter).
My mods: I put a UNI filter on about 2 months ago (before starting the motocross racing) and it's getting a bit dirty, but not horrible. I pulled the light-blue wire from the ignition plug connector.
Here's my predicament. I bougth the bike from Michigan in the wintertime. When I got it back to Kansas, it ran fine (it was still extremely cold outside). As it started to warm up, the bike started running more and more rich, and it started getting harder to start...so I took it to a local motorcycle park's fix=it shop and asked them to adjust my carb for easier starting and to fix a half-throttle stutter (when riding the bike at half throttle...it would choke up and stutter horribly). They adjusted my Pilot Screw and got the bike to where it was a little easier to start, but they didn't even try to take care of the mid-throttle stutter.
When I discovered this, I read through my manual and decided that dropping the needle one notch was my first plan of action. I had read on this forum that some people said that cleaning the carb's passages and jets may help with hard-starting also. So I decided to take the carb apart and clean it when I had the needle out. Moving the clip on the needle was simple...took about 5 min. But when I went to clean the carb, I removed the bowl off of the bottom of the carb, and cleaned it out using Urethane Reducer and Q-tips (it wasn't horribly dirty, but I cleaned all of the surfaces anyway). I then removed the bottom assembly of the carbeurator that houses the actual 'float' assembly. Below this were the needle, main and pilot jets. I started to remove these, one at a time to clean them. When I was done, I saw another copper-colored 'jet-looking' thing and decided to remove it to clean it too...it was the pilot screw, not a jet and I didn't find out how many turns out it was before I started unscrewing it. Once I realized what I was doing...I tried to put it back in, but I'm still unsure about where it was supposed to be. Well, luckily, once I got the carb back together, the bike started, but the idle was way low..so I screwed in the idle adjuster until the bike would hold an idle (it actually wont hold an idle...it's either over reving or dieing...but never a consistent, smoothe idle). I don't have a screwdriver small enough to fit in to adjust the pilot screw, and I was in a hurry to ride, so I loaded up and went riding.
Well, the bike runs okay, but it WONT idle at all...and after I ride it, if I use the kill button to kill it (don't let it die on it's own), it is NEAR IMPOSSIBLE to start again while hot. Not even using the hot start button will help it start. To get it to start hot, I have to pull in the compression release lever, kick it over real quick four or five times, then go through the normal 'starting ceremony', but whne I give it the 'money-kick', I have to give it gas for it to start.
So I took the bike back to the 'motorcycle park fix=it shop' again and asked them to adjust my pilot screw and see what was up with my mid-throttle stuttering (moving the needle down one helped it, but didn't fix it all the way). The owner of the shop started asking me if my valves had ever been adjusted. I told him no, but that the bike only has around 25 total hours on it and I was sure that it shouldn't need them checked yet. He asked me whether it had steel valves or titanium valves. I told him I wasn't sure, but that I thought it had steel. He said that if it had steel, that on some bikes the valves will bang up against the seats and actually dent the valve face, which would decrease the valve's clearance. He said that then, if the valve got hot..the clearance may be completely lost, and that would force the valve open just a hare when it's open...which would make starting it near impossible when hot. He told me to check my valve clearance to see if maybe this was it. I REALLY don't want to check the valve clearance before this weekend's race. Do any of you mechanics out there know what the chances are the at my valves are causing my recent starting problems, or is it just that I have my pilot screw in or out too far (and which do you think it is) and that's making the bike hard to start.
Thanks!
The 'Hopper'
Sorry about the long post.
First, my riding history: I have attended 2 hare scrambles and have raced on an outdoor motocross track 4 times (2 motos per day, 5 laps per moto, plus a 12 min 'practice session' once per day). I have ridden the bike maybe 15 hours of actual 'play riding' at an ORV park in the local area. The oil was changed the day I picked it up, and every 2 weeks since (unless I didn't ride AT ALL during the 2 weeks...then I'd put it off for 2 weeks...if I even rode once during the 2 weeks, though..I change the oil and filter).
My mods: I put a UNI filter on about 2 months ago (before starting the motocross racing) and it's getting a bit dirty, but not horrible. I pulled the light-blue wire from the ignition plug connector.
Here's my predicament. I bougth the bike from Michigan in the wintertime. When I got it back to Kansas, it ran fine (it was still extremely cold outside). As it started to warm up, the bike started running more and more rich, and it started getting harder to start...so I took it to a local motorcycle park's fix=it shop and asked them to adjust my carb for easier starting and to fix a half-throttle stutter (when riding the bike at half throttle...it would choke up and stutter horribly). They adjusted my Pilot Screw and got the bike to where it was a little easier to start, but they didn't even try to take care of the mid-throttle stutter.
When I discovered this, I read through my manual and decided that dropping the needle one notch was my first plan of action. I had read on this forum that some people said that cleaning the carb's passages and jets may help with hard-starting also. So I decided to take the carb apart and clean it when I had the needle out. Moving the clip on the needle was simple...took about 5 min. But when I went to clean the carb, I removed the bowl off of the bottom of the carb, and cleaned it out using Urethane Reducer and Q-tips (it wasn't horribly dirty, but I cleaned all of the surfaces anyway). I then removed the bottom assembly of the carbeurator that houses the actual 'float' assembly. Below this were the needle, main and pilot jets. I started to remove these, one at a time to clean them. When I was done, I saw another copper-colored 'jet-looking' thing and decided to remove it to clean it too...it was the pilot screw, not a jet and I didn't find out how many turns out it was before I started unscrewing it. Once I realized what I was doing...I tried to put it back in, but I'm still unsure about where it was supposed to be. Well, luckily, once I got the carb back together, the bike started, but the idle was way low..so I screwed in the idle adjuster until the bike would hold an idle (it actually wont hold an idle...it's either over reving or dieing...but never a consistent, smoothe idle). I don't have a screwdriver small enough to fit in to adjust the pilot screw, and I was in a hurry to ride, so I loaded up and went riding.
Well, the bike runs okay, but it WONT idle at all...and after I ride it, if I use the kill button to kill it (don't let it die on it's own), it is NEAR IMPOSSIBLE to start again while hot. Not even using the hot start button will help it start. To get it to start hot, I have to pull in the compression release lever, kick it over real quick four or five times, then go through the normal 'starting ceremony', but whne I give it the 'money-kick', I have to give it gas for it to start.
So I took the bike back to the 'motorcycle park fix=it shop' again and asked them to adjust my pilot screw and see what was up with my mid-throttle stuttering (moving the needle down one helped it, but didn't fix it all the way). The owner of the shop started asking me if my valves had ever been adjusted. I told him no, but that the bike only has around 25 total hours on it and I was sure that it shouldn't need them checked yet. He asked me whether it had steel valves or titanium valves. I told him I wasn't sure, but that I thought it had steel. He said that if it had steel, that on some bikes the valves will bang up against the seats and actually dent the valve face, which would decrease the valve's clearance. He said that then, if the valve got hot..the clearance may be completely lost, and that would force the valve open just a hare when it's open...which would make starting it near impossible when hot. He told me to check my valve clearance to see if maybe this was it. I REALLY don't want to check the valve clearance before this weekend's race. Do any of you mechanics out there know what the chances are the at my valves are causing my recent starting problems, or is it just that I have my pilot screw in or out too far (and which do you think it is) and that's making the bike hard to start.
Thanks!
The 'Hopper'
Sorry about the long post.