kdx won't kick start when hot

[kdexd]

Hi, I just bought a 2000 kdx 220, after riding it yesterday for the first time, the bike won't kick start after I have been riding for a while. It's got a new plug, clean air filter, new gas running 32:1 mix. It will compression start and it will kick start when cold. Any ideas? Thanks!

 

[Chokey]

The top-end is probably worn out. With worn piston/rings, the kickstarter can't spin the engine fast enough to generate enough cranking pressure for the engine to fire. Bump-starting spins the engine faster, generating higher pressures that will allow the engine to fire.

 

[kdexd]

Thanks, I did notice a lack of pressure when I was trying to kick start it, but it will kick start when cold.

 

[Chokey]

The intake is still cold, so the air being drawn into the cold engine is denser than air being heated in a hot intake. The cooler denser air creates enough of an increase in cranking pressure for the engine to fire when it is cold.

 

[steve.emma]

hmmm no compression?? maybe.but a 220 doesnt have that much compression anyway compared to a mx bike. to prove weather or not lack of compression is the cause of the problem i would carry out a compression test and see what reading you get.
i would think that if it had very low compression it wouldnt start when cold let alone hot. you might be better off to check what jets you are running in case its a mixture problem. also you say it doesnt start when hot but are you cracking the throttle when you start it?

 

[kdexd]

Just had a compression test done, 165 psi. The mechanic said compression would be the same whether the engine was hot or cold. I do not touch the throttle when I start it, hot or cold, I have a fouled plug phobia. The mechanic thinks a electrical problem somewhere. When it is cold there is compression although not much because it is just a 220, but there was a definite difference when hot. Also I always positon the piston at the top of the cylinder before I kick it so I get a full stroke

 

[dixie]

Give it some Gaaaassss, Said early CRACK That throttle.

 

[steve.emma]

yeah like he said, give it some gas AS you kick it. although when cold starting a bike its better not to touch the throttle the choke will take care of things. but when hot it needs some airflow. your compression sounds good for a 220, that wont be your problem. if you suspect an ignition problem then just check for spark when its hot and wont start.

 

[kdexd]

Thanks for the help!!

 

[QLD_KDX]

check you reeds as well. If they are chipped or just not sitting flat it will be a bitch to start. Happened to me racing MX - I would get it started, warm it up, take it over to the start line, shut it down - then couldn't start the SOB and ended up still at the gates at the start :bang: New reeds fixed all that.

Andrew

 

[glad2ride]

Give it some gas, like the manual sayeth.

 

[crrod]

I don't know about the KDX, but my Honda manual says if the bike doesn't start with no throttle in 2 or 3 kicks, go WOT and kick it. I've had to do this a couple of times when no throttle didn't start it when hot. When using the WOT when hot, it has yet to fail to start on the first kick.

 

[krazyinski]

Picture this, humidity 50% temp around 90 degrees, a 20' up hill step up double rooted trail with a two foot gully to one side. Some how ? the bike ends up side down on its side with the foot peg hung on a root after lots of cursing and pulling, mean time fuel is pooring out the bike comes free. after a 2 or 3 minute break bike right side up,THROTTLE WIDE OPEN TWO KICKS off we go and this time lets not look at the gully.


Read up and get the basics dialed in. you have one of them compression, now work on fuel, air and spark. how? more basics check the carb, float level, base line jetting ? pilot? needle?and clip position? air screw adjustment?Main jet? see whats there and where you need to go. how about that airbox and air filter? spark plug what heat range? age and condition of the plug? are you oil fouling or fuel fouling the plug?

there is alot to answer and might be a bit overwelming but take it one step at a time.

90% of the time its one of these things being off that causes problems.

get it right and reliability is what you get wash and ride. then its all about riding and smirking at others with problems.