2014 YZ250F extremely hard to start

hi all,

I just bought a used 2014 yz250f in very good condition.  When cold it will take about 50-100 kicks to start but when warm it will sometimes start on the first couple but sometimes it will also take alot of kicks.  Ive just been giving up and bump starting the bike.  Motor has very good compression and only has about 25 hours on it.  The valves are where they should be i just checked.  Any help would be greatly appreciated. Im about to take it back to the guy and demand my money back.

 

Thanks 

Luke 

Do not twist throttle

Are you pulling the 'choke' out when cold?

Do not twist throttle
Are you pulling the 'choke' out when cold?

Yes I’m pulling the choke out and not twisting the throttle at all
5 hours ago, luke8500 said:


Yes I’m pulling the choke out and not twisting the throttle at all

im thinking its also becuase the previous owners were running 110 race gas. will drain tank and put 91/92 in it and see if it gets any easier to start

 

 

19 minutes ago, luke8500 said:

im thinking its also becuase the previous owners were running 110 race gas. will drain tank and put 91/92 in it and see if it gets any easier to start

 

 

Has the motor been ported or polished at all? Has it had any head work? 

 

Were you running 87 gas? never do that again, with any dirt bike. Always run at least premium. 

Has the motor been ported or polished at all? Has it had any head work? 
 
Were you running 87 gas? never do that again, with any dirt bike. Always run at least premium. 

Motor is all stock. Never ran 87 gas in it. Had a tank of 110 when I bought it 2 days ago and I think that’s causing the hard starting. I’m going to drain the tank and put 93 in it. Would that help?

Could very well be

Higher octance fuel burns slower and I believe harder to ignite

Absolutely no benefit in using it unless engine needs the higher octane due to compression ratio and ignition advance. If any thing it'll make less power due to its slower burn rate, if used in a std engine

Could very well be
Higher octance fuel burns slower and I believe harder to ignite
Absolutely no benefit in using it unless engine needs the higher octane due to compression ratio and ignition advance. If any thing it'll make less power due to its slower burn rate, if used in a std engine

The motor is all stock. Tonight I’m going to drain the tank and put 93 in it

I know heard a few years back in extreme cold conditions that they recommended low octane fuel for better start ups .

Should fire 1st or second kick, hot or cold, pump or race gas.

My 14 likes just a slight bit of throttle to start. If the problem isn't your technique then you'll need to get the manual out and start troubleshooting.

Should fire 1st or second kick, hot or cold, pump or race gas.

My 14 likes just a slight bit of throttle to start. If the problem isn't your technique then you'll need to get the manual out and start troubleshooting.

I diluted the race gas with a bunch of 93 octane pump gas. Put a new plug in it and noticed a big kink in the fuel line that looked like it has stopping the bike from getting gas so i rerouted that and it started 5th kick yesterday cold. It’s about 35 degrees outside in Ohio

If the kink was the cause then it would have stopped it running or starting hot as well.

Good you found it but not the cause IMHO

I read that putting an exhaust cam out of a 2015 would help starting.  Is this true?

 

30 minutes ago, GuyGraham said:

If the kink was the cause then it would have stopped it running or starting hot as well.

Good you found it but not the cause IMHO

i read that putting an exhaust cam out of a 2015 would help starting.  Is this true?

On 11/9/2017 at 8:09 AM, luke8500 said:

i read that putting an exhaust cam out of a 2015 would help starting.  Is this true?

where did you hear that?

 




where did you hear that?



 

Some other ThumperTalk forum. Supposedly the exhaust cam for the 15s were modified for easier starting.
On 10/11/2017 at 0:09 AM, luke8500 said:

i read that putting an exhaust cam out of a 2015 would help starting.  Is this true?

It will make it easier to kick over, but isn't your problem. My 14 started within a couple of kicks usually. 

Are you kicking it properly ? Have you had a 4 stroke before? 




It will make it easier to kick over, but isn't your problem. My 14 started within a couple of kicks usually. 



Are you kicking it properly ? Have you had a 4 stroke before? 

Yea I’ve have lots of 4 strokes before. I put a new plug and fresh gas in this one and now it starts cold within 3 kicks

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