Bike having trouble starting and running when cold

[jwollam]

Hi everyone!
Bike is a 2008 Ninja 250
I was hoping someone could provide me with a few tips. Over the weekend we dang near stripped my bike down to the frame, removed the factory airbox and the clean air system (thank you California!), rebuilt and jetted the carbs (currently with 110 mains @ 3 turns out), and installed a full area P exhaust.

The bike runs great when its warm. However this morning I went out to start it up to go to work (32º outside this morning). I put on full choke and went to start it. It started like normal (with stock everything) However it would never kick up to that high idle (my indication it's okay to ride). The bike just kind of chugged along and would eventually take throttle inputs without wanting to die. Hopped on and started going down the road (had to keep the rpm's low to keep noise down in a residential neighborhood) I got about a mile out and the bike started sputtering and eventually died (I think I flooded it). After a few minutes it started back up and got me to work. Went for a ride at lunch, and it runs like a champ, went again after work and no problems at all.

So after my short novel, here's my question... Is there some trick to get this bike to warm up and ready to ride after putting larger jets in, etc...?

Thanks!
-Johnny

[Motofool]

Does the bike has a thermostat in proper working conditions?

Did you try with less or no choke?

[jwollam]

Originally Posted by Motofool

Does the bike has a thermostat in proper working conditions?

Did you try with less or no choke?

The fan seems to kick on when it normally should, I don't have any indication that the thermostat isn't working correctly.
Tried it with no choke and it wouldn't start, once running though I was able to take the choke off and it ran fine.

[Motofool]

I asked for the thermostat because it is to remain closed until the engine heats up the coolant around the cylinder and head.

Since that is no much mass of coolant, it should heat up relatively quickly and then force the T-stat to open.

If there is no T-stat or it is stuck open, then the pump forces the coolant to flow through the cylinder and radiator, taking much longer to warm up.

An easy way to test it is to hold the hose going to the radiator during the first moments after start up.

I asked for no choke, thinking that your mix may be too rich with those jets.

Just a couple of ideas.

[jwollam]

Originally Posted by Motofool

I asked for the thermostat because it is to remain closed until the engine heats up the coolant around the cylinder and head.

Since that is no much mass of coolant, it should heat up relatively quickly and then force the T-stat to open.

If there is no T-stat or it is stuck open, then the pump forces the coolant to flow through the cylinder and radiator, taking much longer to warm up.

An easy way to test it is to hold the hose going to the radiator during the first moments after start up.

I asked for no choke, thinking that your mix may be too rich with those jets.

Just a couple of ideas.

I appreciate all the help, thank you!
I think it's just trying to get a bike to start up and stay running with this large of a jet (not trying to sound like a newb) It looks like most people start with at least 112's and then move up towards 115's to get the bike dialed in.
I can imagine it's just part of starting a bike with that large of jets. Of course being 32 degrees out in the morning probably doesn't help much either.

[DaBlue1]

32 degrees is pretty cold, so your warm up time may be a little longer. Your pod filters don't help the situation much. You now have much more cold air to deal with along with cold fuel. Depending on the weather conditions you could have suffered from carb icing. I noticed the work you did to the carbs, but did not notice if you changed the plugs or not. I would change them to a set of iridium plugs to help prevent fouling and burn the extra fuel you've added a little better.

[jwollam]

Originally Posted by DaBlue1

32 degrees is pretty cold, so your warm up time may be a little longer. Your pod filters don't help the situation much. You now have much more cold air to deal with along with cold fuel. Depending on the weather conditions you could have suffered from carb icing. I noticed the work you did to the carbs, but did not notice if you changed the plugs or not. I would change them to a set of iridium plugs to help prevent fouling and burn the extra fuel you've added a little better.

I'll get a set ordered up tomorrow, thank you for the advice. I think it just has stock plugs in it right now. Is there one particular brand you would recommend?

[DaBlue1]

Originally Posted by jwollam

Is there one particular brand you would recommend?

Either NGK CR8EIX or Denso Iridium IU24. The NGK will probably be easier to find locally.

[jwollam]

Originally Posted by DaBlue1

Either NGK CR8EIX or Denso Iridium IU24. The NGK will probably be easier to find locally.

I'll see if I can find the NGK plugs. Do you think I'd benefit from upgrading the wires as well? The wires on the bike are stock, about 5 years old, sat in the Vegas heat for 4 of those years. No indications their faulty, but since I'm doing the plugs... lol

[DaBlue1]

Originally Posted by jwollam

. Do you think I'd benefit from upgrading the wires as well? The wires on the bike are stock, about 5 years old, sat in the Vegas heat for 4 of those years. No indications their faulty, but since I'm doing the plugs... lol

If you feel the wires are in good shape, there's no need to replace them. Upgrading the wires or coils will require some modification and a bit of money

[jwollam]

So the bike is definitely running rich now. Will pick up some plugs tomorrow and see if I can dial down the mixture some.