My bike turns a little snotty if its hot and humid and I'm riding it for hour at slow temps... its simply because its a 4 stroke. First of all, no engine likes to be hot. But when 4 strokes are hot and stall, they are sometimes a bear to get restarted. Thats why MX bikes have hot starts. But now, they are usually built right in and are utilized automatically. Usually you had to open it manually. And it took fresh cool air in from inside the frame.

But I think proper jetting is a good way to combat this as many people, including myself can start the bike when hot. However, like I said, its snotty with me, you can tell it doesnt like it.

 

You live in the desert though, mate.....it gets so humid here in the Eastern US that you can see haze in the air like the jungle on a bad day. Hell, when I was shooting today at the range my scope was fogging a bit looking at the longer distances.

 

So in your opinion, is my jetting OK, Jason? Or should I make changes? Screw in the A/F a half a turn? Or do I need to wholesale redo it... smaller main jet? I've always been told its better to run it rich than lean. I know with the lid off the bike didn't feel so good to me so I put the lid back on. And its normal for our bikes to be a PITA to start hot? That's not a jetting issue? If that's not a jetting issue then F*** it I'm gonna leave the jetting alone.

 

When it's hot out, the air is thinner, so you'll be running a little rich assuming it was jetted well for cooler temps. It's easy enough to adjust the fuel screw, so may as well try it and see. Can't hurt.

 

To drain the carb bowl unscrew the little allen screw on the bottom of the carb. You will see the fuel poor out of the hose coming straight out the bottom. Thats how I start it after I flood it.

 

This bike can be a problem child to start cold but hot starting in any weather has never been a problem. That's the feedback I've had since owning mine, although mine has always started cold without issue (slight differences in the AUS/USA specific models?)

IMHO it's not a problem I've read a lot about, so I'd say it's uncommon. You need to "SET" the fuel screw to your bike specifically. Trying half a turn either way may help so give it a go. It may be all the bike needs. I suspect your jetting is pretty close. How' s your air filter maintenance?
The main cause of bikes poor starting hot or cold (4 strokes) is poor valve clearances. How many miles on your bike and are the valves in spec.

I keep the appropriate size allen key in my tool kit, it's always at hand then.

 

Maybe I'm just tired but I read through everything real fast again and I'm only getting vague issues. Could you please specify what exactly your having a problem with. As in how its running, when your having these problems, things that are happening near that time. But just off the top of my head, your jetting is probably damn close, probably an AF screw adjustment.

You gotta remember, your riding in Weeeeezy-anna. Its freaking A hot and humid down there...swamp country. That air is thing from being hot, and filled with water vapor. I don't know how in the hell you guys stand it down there. I've been down south in the summer multiple times and I couldn't wait to get back to PA. Much more comfortable in the summer. haha

 

yeah, people always say about how cold blooded this bike is, but I've honestly never had a cold problem at all. Down into the 40's F this thing starts no problem. And over the winter, I went out and started it up a few time for the hell of it, just to keep it running. I took a little space heater out and put it in front of the engine, like a ghetto diesel glow plug. And it didn't warm it for more than a few minutes and it fired right up. I didn't even try to start it without warming it because I had fear of flooding it. It may have started, I don't know.

 

The only problem I ever have with it lately is hot starts but my air filter WAS kinda crusty. I just cleaned and oiled it before i brought it in. The mech said the valves looked good, were still well in spec... so assuming he's not on crack, my engine is good to go... I'ma try turning the A/F screw in a half a turn and see if it runs better. When it is hot outside and the bike is at temps it idles really low... and like I said its a PITA to start when the ibke is hot. That's my only issue. I've never had a problem in the cold, either. Bike always runs good in the winter to me.

 

Cliffsta,

I've had my '07 for just over a year now and have been slowly gathering the parts for the carb and airflow mods. All thats left to get is the KDX snorkel and a couple of bits for the smog and carb/crankcase breather. One of the reasons I have waited to make the mods is to find out what kind of issues (decel popping, hard starts etc) pop up as a result of the mods. So far I haven't seen anything that concerns me.

So I know my bike is lean and corked up right off the bat. I'd say my riding conditions are very close to yours - hotter 'n a two dollar pistol and humidity off the charts. On a cold start I have to use the choke always, leave it on for 5-10 seconds and good to go. Hot start just hit the happy button for less than a second and she purrs like a kitten. I dimly recall a couple of occasions where it took two or three tries to get is started hot, but they have been so rare that I've never thought of hot starting being any kind of issue.

There's your baseline. Stock bike, similar conditions, no starting problems. For the record, when I do my mods in the next month or so I'll be going with the same setup you have except for the addition of a Kouba screw. Not expecting any problems once I dial it in. I wonder about your mechanic who thinks the DJ kits have inferior parts. In my experience the vast majority of aftermarket parts are much better than the stock stuff they replace.

Good luck.