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2012 Cranky to start questions

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I know some of the CRF250s are cranky or difficult to start and it depends on the years.  My 2012 takes 20-30 kicks to start on a cold day (40 degrees F or less) and even 10 on a nice day when the machine is cold.  I read the FAQs and did the following as part of my winter maintenance and was hoping to improve my starting:

NEW Twin Air filter right out of the bag pre-oiled

NEW spark plug

Adjusted valve lash to .005 intake, .009 exhaust

Cleaned the coil, wire and connections thoroughly.

This is an EFI engine and I do not understand why it would be finicky. No amount of throttle twisting is going to do anything since these do not have an accel pump.

After this maintenance I have exactly the same problem! My starting procedure cold - pull out fast idle knob, slow kick 3-4 times to prime fuel pump, get kick lever back to TDC, kick reasonable speed (not a fast kick like a two stroke).  I have read all sorts of non-sense about blip the throttle three times, hold it open a smidge etc. Just seems like this is masking a problem that could be addressed or they are old wives tails.

Once it fires you are good to do - settles down and idles great on fast idle for 30-60 seconds push in knob.  Runs like an animal I love this thing.  Just a beast to start.

I did not do the de-compression mod that seems to be an '06-'08 era mod but maybe I am incorrect.

 

Thanks!

 

 

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Hard to start 4-stroke issues are more often than not valve or fuel related.

 

Your valve lash may be within specs but:

-how many times have they been re-shimmed?  (how many engine hours,cylinder head ever been serviced ?)

Despite having proper lash, the sealing surfaces (valve face and valve seats) may be worn and allowing compression to escape while cranking.

A leakdown test would give you an indication if so.

-do the timing marks relative position show any sign of chain stretch?

 

-fuel:

-has the fuel injector ever been cleaned?  Pump pressure verified etc.

Many suggest pre-filtering the fuel BEFORE filling a FI bike's tank.

Edited by mlatour

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I do not know how many hours are the engine but the bike had relatively little use.  When I shimmed it I think it was the first time and it was only out by .001.  The shims did not have any marking on them making me think they were original.  I would like to do a leak down test that would be interesting.  Timing marks looked perfectly level in line with the head when the dot was lined up with the pointer in the cranks case.

I have never cleaned the injector and I suspect no one ever has.  Is there a procedure for this?  Wouldn't a dirty injector or weak fuel pump show other symptoms while I was riding it?  It has killed throttle response and runs amazing.

I am going to look at the pre-filters that seam like a no brainer since the fuel cans always seem to have something in them.

 

Thanks

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Sorry can't help you with any injector related maintenance tips, never tinkered with any FI bikes.

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