So my bike has always been hard to start since I've owned it. PO told me to always give it 3 pumps of the throttle when starting for the first time and kick until it starts. That worked but I am tired of kicking this thing over 30 times and never know if it will start. Now I can't even get it to fire. Has good spark and I had the carb completely apart and cleaned. Checked and adjusted the exhaust valves. Intakes were fine. Timing is right on. Don't know what else to try . I can't even push start it because it has a Rekluse clutch

Here is what I have:

The bike is a 04 KX250F and here is what I know from the PO:

**Motor**

2004 crank cases
290cc Athena big bore kit
stock 2006 honda crf 250f rod
2006 kx250f crank stroked 59mm
possible aftermarket pipe (not sure what it is though, no label on it)

** Jetting**

Starter Jet 68
Pilot Jet 48
Main Jet 185
Leak Jet 60

Any ideas????????

As strange as it may sound, a big-bore engine usually has to have smaller jets, even if power is increased.

The bigger engine pulls a greater vacuum, which sucks more fuel from the same size jet.

48 is a bigger pilot jet than most 450´s use. Try a 40 or 42.

Also, don´t kick too fast. Find TDC and return the kickstarter all the way up.

If it was my bike I'd start off from scratch and check everything, is the spark strong enough? Is fuel getting through ok? Have you tried doing a compression test?

Richard is spot-on.

Start over.

Get a new spark plug.

Don´t twist the throttle 3 times, just 1.

The 04´s were never super easy to start, they changed the CDI and carb multiple times to get easier starting bikes.

Some 04´s even had broken CDI´s, but they should all be replaced by now.

Also, inspect the coil and high tension lead.

the_dixtar said:

I'll try and get a compression test done tonight. I know it's getting spark, but how do I know if it's "strong enough"???

D-K said:

I ordered some new plugs last week, should be here tomorrow. I'll try and change out that pilot, I think I have a 42 laying around.

UPDATE: So I got the new plugs today and put a new one in. It seems like it isn't getting fuel, so I pulled the drain on the float bowl and turned the fuel on..............nothing! So I pulled the float bowl cover off and it was bone dry! I adjusted the float and put it back together. Did the same test again and fuel starting pouring out, so I know I have fuel in the bowl now. I kicked it over no less than 50 times and still no go. It sounds like it wants to start about every fourth kick, but just won't. Not sure what I am gonna try next, my leg is sore

Possible is a cdi issue.. 04s were notorius for having an issue with the cdis.. it could be creating spark but at the wrong time.. also, you could have a valve issue.. you said the exhaust was off.. was it zerod?  if so I would say possible bent valve resulting in little to no compression..

If you know anyone else with a running 04 try using the cdi off that bike and see if it runs..

Pr1malR8gw said:

So as far as the CDI, can this be tested at a dealer?? I don't know anyone off hand that has a similar bike. I'm about ready to just buy a new one

Some (bigger) dealers can test the CDI under a simulated workload. Not just measuring with an Ohm meter.

I saw a moped shop a couple of years ago who tested CDI´s this way.

D-K said:

I'll call my dealer today and see if they can test it. Honestly, I hope that's the problem. If not, it's getting sold as-is!!! I've had it. I'll just keep riding the 2 smoker................

when I get my stripped oil drain plug issue resolved and fire up my bike, i will swap out to this extra cdi that i purchased and test it. if it works, I will sell it to ya for whatever I bought it for...it was a good price if i recall. at least this way you will know that it is a functioning CDI, and not taking a random gamble on ebay. I really don't even know if it works because I never installed it.

my 04 gave me problems, and it turned out to be a leaking valve that I found when I performed a ghetto rigged leak test.

hotnanas said:

Sounds good. So am I understanding correctly, even if the CDI is not working properly, I can still have spark??? Because it seems like I have good spark there, but maybe at the wrong time???

Would you guys forget about the CDI, its a black box it either works or it doesnt, you have spark, so it works. The obvious problem is the fuel issue you said yourself you found.

Make sure valve clearance is DEAD on, then take the carb off and shoot a little starter fluid in there. If it starts (mostly likely will if its a fuel issue) then thats your problem.

No fuel = it ran lean = no start
Fuel overflowing =  running way too rich = no start. Take the carb apart, look at the float valve, thats most likley your problem.

DB 450r said:

Valve clearance is right on now, already addressed that issue. Adjusted float last night. Have not tried starting fluid (I prefer just spraying fuel), but I can give that a shot. I'm out of things to try. I did try putting a little fuel in the cylinder, but didn't seem to change the way it reacted..........

I really recomend starting fluid. You need an adomized fuel to burn, this works very well.

2 aditional comments, make sure your gas is still good, and i find that when i put the piston at TDC then kick it over, it starts much easier than just kicking away.

keep us updated

DB 450r said:

OK, I will be working on it this weekend. I'll post with results (hopefully good ones)!!!!

Thanks

can you push start it? (which reckluse?...have perch?)

it could be the valves not seating properly...even with the right clearances. that's why I suggest a leakdown test.

EDIT: for the life of me, i can't find where I saw how to bump start the bike by adjusting the engagement point...will dig around some more. I haven't tried bump starting with my rekluse. right now i keep finding that you can do it if you add to the clutch pack, but that isn't the method I am looking around for.

Edited by hotnanas, 08 April 2011 - 08:18 AM.

DB 450r said:

Not true. I had a 2 stroker that the ignition coil was shorted. It had spark but it was not in sync with the timing. Replaced it and it ran great.

did you do a compression test?

what was the outcome?

onekawboy said:

I probably wont get to that until Monday. For some reason my kit doesn't have the correct fitting and wont screw into the head, even though the threads look exactly the same. I thought my kit had all the different ends but apparently not. I need to borrow one from a buddy