01 YZ250 not starting after carb rebuild

[YZ250Guy]

I have just rebuilt my card (put it back to close to stock) and now the bike does not start at all. I have done alot of work to it so I will list what I have done in order.

1. Just bought the bike (I was told it never recieved a top end) The bike was also kinda hard to start but it did not run as good as it should have
2. I rebuilt the top end. After I completed this I started the bike with the old gas that the bike came with (it only took me a few days to rebuild the top end). Bike ran just as good as before.
3. I drained the remaining gas becuase I did not know how old it was and the manual told me to use 20:1 ratio. I put in 1/2 of 110 octain fuel and 1/2 of 93 octain fuel at a 20:1 ratio (Yamalube 4R)
4. The bike did not start and I was told that this ratio was too far off and that I needed to put in a 40:1 ratio. So I rebuilt the carb. it originally had the following
Needle: N3CJ-2
Main: 175
Pilot: 45
Power: 50

I replaced the above with the following
Needle: N3CJ-2 (not stock) (I think I put the old needle back in. I meant to put in the N3EJ-2 (stock)). If I did put the 3CJ back in then the settings would equal the N3EJ-2.5 setting.
Main: 175 (stock is 178 but the manual says do 175 if temp is 75+)
Pilot: 50 (stock)
Power: 50 (stock)

5. I put in the fuel at 1/2 of 110 octain fuel and 1/2 of 93 octain fuel at a 36:1 ratio (Yamalube 4R)
6. I also put in a new spark plug (NGK BR8ES) with a gap of .021 (the old plug was set at .028)
7. The bike would not start with the air screw being set at 3/4, 1, 1 1/4. (Also the idle screw was out 3 turns, and I tried it at 4,5 turns)
8. I adjusted the spark plug to be at .028 becuase that is where the old one was at and it still does not start.

There is fuel on the plug when I pulled it out and I do have a spark plug tester (not like the one in the manual though). I have also not adjusted the throttle cable at all. (I am assuming that the idle adjuster will take care of that till I get the bike running)

How do I start troubleshooting what is wrong so I can start the bike so I can tune it like the manual says? Oh.. I live in Northern VA where is has been 75+ with lots of humidity. Thanks for the long read.

 

[bclapham]

if there is fuel on the plug, it sounds like its not sparking. put the plug in the cap and lay the plug on the head and then kick the bike over- you should see it spark- its that simple. then check all connections, earth points and the kill switch.

btw- i run 32:1 race gas and lean the bike out a lot- 45P needle posn. #1 (top) and 172 main. dont be afraid to experiement leaning it out, despite what the mags say with their specs, i dont think jetting has anything to do with it not starting.

good luck

 

[YZ250Guy]

I pulled the plug and it sparks great. I also used my tester and I get 8mm+ spark (that is all the tester will do) The manual says 6mm min. Can I be getting too much fuel? Also what is the stock amount of turns out for the idle adjuster? Is there anything else I should check? I did check all of the wiring and it looks like it is in place. (ground was good and the kill switch is working like it should)

 

[tiller]

Look closely at the bottle your oil came in. You stated you are using Yamalube 4R. This is a four stroke oil and never was meant to be used as a premix in a 2 stroke. If you want to use Yamalube you need to get the Yamalube 2R.

 

[smarttoys]

Look closely at the bottle your oil came in. You stated you are using Yamalube 4R. This is a four stroke oil and never was meant to be used as a premix in a 2 stroke. If you want to use Yamalube you need to get the Yamalube 2R.

That's exactly what I was going to say when I read the original post but I figured it was just a typo.

 

[bclapham]

i think we might e ready for a Homer Simpson moment!

doh!:)

 

[YZ250Guy]

Thank goodness that was a typo. I use 2R premix and I use Yamalube 4 (10W40) for the bottom end. Anyways I am a lot closer then I was before. I did get it to run. I figured that the only thing that I have not done was adjust the throttle cable and that I might as well do it. After adjusting the cable (I just guessed but I tryed to put it where it was before) it started right up. In fact it started then maxed out the RPM's. I have not read the manual but I am hoping that it will tell me how to adjust it (in junction with the idle adjuster). I played with the cable adjuster on top of the carb and at the lever to where it idles ok. My problem now is when you pull the choke it is supposed to give more gas then with the choke in. I can't seem to find the fine line to where the cable is adjusted correctly and when I pull the choke out it is giving enough gas to start it (I also have no idle where the idle adjuster is supposed to be). Unfortunitly it started to rain so I have not had time to play with the cable some more (and the idle adjuster). Any ideas on how to adjust this or is it in the manual?

 

[490Dave]

You will need to have the bike running to adjust the idle, as far as adjusting the cable, once you have the idle set where you like it begin to take the slack out of the cable until the idle increases then back off a turn and you should be set.