2012 crf250r won’t start

Related:
Create New Tag

8/30/2018 9:27 AM

My bike will not start I’ve just checked and shimmed the valves, replaced my kill switch because that is a known problem on these bikes when they will not start, checked the spark and fuel pump and am getting both spark and fuel now. I have gone through every connector and everything I have tried I can not get the bike to start. Please help!!

|

8/30/2018 9:34 AM

Motor timing

|

8/30/2018 9:45 AM

Not the timing just rechecked it

|

8/30/2018 9:46 AM

Will it start if you put some gas down the spark plug hole? Injector could be blocking gas flow

|

8/30/2018 9:59 AM

No it did not start doing that either and it still does have spark

|

8/30/2018 10:01 AM

Can you bump start it?

|

8/30/2018 10:09 AM

When was the last motor work done on this 6+ year old bike?
Valves leaking, poor compression, poor fuel flow, weak spark ( any color other than bright blue) or timing issues would be things to recheck.
You say the valves were reshimmed....How many times has this been done? How much change was there?

Paw Paw

|

8/30/2018 10:09 AM

Nope can not bump start either

|

8/30/2018 10:17 AM

Is your timing chain fresh? If its old and stretched your motor wont be in time even tho it looks like it is.

Last thing i can think of is old valves and seats or a worn piston/rings.

Does the auto decomp work? Its not stuck and leaving an exhaust valve open?

|

8/30/2018 10:19 AM

I just rebuilt the top end just because of hours the bike has 60 hours the valves have been checked every 15 hours this past time was the first time that needed reshimming the intakes were right on spec and the exhausts were .013 and .0135 they are supposed to be .011 where they are now the bike was not running before I did the rebuild. It first would not start after I did the fuel filter but I know the fuel pump is not the problem because their is fuel in the line and I have taken it apart and checked to see if it was pumping three times now it has good spark the old plug was good just replaced with piston and the compression is good no leaking valves I would think it would be electrical but there is good spark

|

8/30/2018 10:34 AM

How did your valves go from .011 to .013? They get tighter over time not more loose. The only reason valves can get loose over time is from carbon build up on the seats. That will cause them to stick open and not seal - and not allow the bike to run.

|

8/30/2018 10:52 AM
Edited Date/Time: 8/30/2018 11:27 AM

From what I’m gathering this is a fresh top end? Piston, valves, etc??? The fuel pump still could be your issue... the only way to know for sure is to check inline fuel pressure... just because it flows fuel doesn’t mean it’s a good working pump... the fact that you can’t bump it leads me to believe your problem lies somewhere along those lines.... if the fuel pump checks out and the top end is fresh I’d run a leak down test just to make sure the valves are sealing...

|

8/30/2018 11:42 AM

kb228 wrote:

How did your valves go from .011 to .013? They get tighter over time not more loose. The only reason valves can get loose over time is from carbon build up on the seats. That will cause them to stick open and not seal - and not allow the bike to run.

X2

Paw Paw

|

8/30/2018 11:45 AM

Remember that "good spark" and a "good bright Blue spark" are not the same thing.
You can have several different colors in a spark and it will still not fire the plug.
How do you know if the injector is clean? Clean it.

Paw Paw

|