Posts
35
Joined
11/3/2017
Location
Rockford, TN
US
Edited Date/Time
9/9/2022 3:32pm
HELP! I have a 2010 CRF250 that will not kick or bump start. This started after a top end rebuild due to zero valve clearance. Bike started on 3rd kick. Came up to temp, attempted to ride varying throttle up to 1/2 then bike backfired and shut off. Pulled valve cover and timing was 180 out ( was spot on when rebuilt). Removed head and checked for damage, none found. Reassembled and set timing again per manual, now it will not kick or bump start and red light on kill switch does not blink or come on when trying to start. With air filter out can see into throttle body and there is no fuel being sprayed when kicking bike over. Here is what has been done/tested:
New Pro X valves/seats/springs and retainers
Head machined
New Hot cam stage 1 - replaced hot cams stage 2 that came in bike
New Honda timing chain
New Pro X piston and rings
Cylinder honed/cleaned up
All new honda gaskets during rebuild
New spark plug
Clean/properly oiled filter
New oil filter and oil
New Honda AIT sensor
New fuel injector
New Honda fuel pump and filter
Tank cleaned as precaution
Has Tokyo Mods sticker on ecm but previous owner did not state it was tuned.
Tested all of wiring harness - has continuity thru all wires
Tested stator - out of spec so was replaced with new one
Coil checks good
Regulator in spec
Spark plug has good spark when grounded to case
Compression test in spec per manual
Ground is clean, even switched ground location to be sure
Condenser test in spec
Injector shows 13 ohm - spec is 12.4 - sprays when power is applied directly
Kill switch test good, unplugged and tested all
Fuel pump pushes fuel when kicked over or power applied directly
Have new coolant temp sensor but have not installed it.
I do not have an extra ecm to test with. At a complete loss as to what is wrong.
New Pro X valves/seats/springs and retainers
Head machined
New Hot cam stage 1 - replaced hot cams stage 2 that came in bike
New Honda timing chain
New Pro X piston and rings
Cylinder honed/cleaned up
All new honda gaskets during rebuild
New spark plug
Clean/properly oiled filter
New oil filter and oil
New Honda AIT sensor
New fuel injector
New Honda fuel pump and filter
Tank cleaned as precaution
Has Tokyo Mods sticker on ecm but previous owner did not state it was tuned.
Tested all of wiring harness - has continuity thru all wires
Tested stator - out of spec so was replaced with new one
Coil checks good
Regulator in spec
Spark plug has good spark when grounded to case
Compression test in spec per manual
Ground is clean, even switched ground location to be sure
Condenser test in spec
Injector shows 13 ohm - spec is 12.4 - sprays when power is applied directly
Kill switch test good, unplugged and tested all
Fuel pump pushes fuel when kicked over or power applied directly
Have new coolant temp sensor but have not installed it.
I do not have an extra ecm to test with. At a complete loss as to what is wrong.
Even if you can’t tell by looking at them
I’ve seen Honda cam tensioners fail
I’d be looking at that myself
Cam chain slipping or a cam gear slipping 180 would be highly unlikely but that’s what you’ve found
And without damage to the valves
Also highly unlikely
Valves are good
Tensioner good
Replace the only other culprits you haven’t checked as mentioned Coolant temp sensor and ecu
If they aren’t the issue start over and double check every thing you’ve already checked
The Shop
A bike will not start 180 degrees out of time. I would go back and confirm you are at TDC when you set cam timing, put a degree wheel on it to be sure.
The backfire could have caused the cam gear to slip putting it out of time despite the marks are lined up.
https://www.manualslib.com/manual/1062502/Honda-2010-Crf250r.html
Pit Row
Pay attention if the bike will stay running on its own after being started with starting fluid. On these non-battery non-estart EFI bikes, the voltage supply for the injector comes from one path to start (condensor) and another once the bike is actually running and spinning the generator. This will help you narrow down likely causes.
You ever find the issue? I’m on your boat right now. 90% of the bike is new and still won’t crank. Just thought I’d ask. Thx.
Yes. The stator woodruff key had sheared just enough to allow the ignition timing to be off, replaced it and starts on 2nd kick everytime. 3$ part was the problem.
Same issue. 3rdgearpinned, how about you . Find the culprit. Mine has been sitting for almost a year. 3 cams later still nothing. I’ve replaced everything. Even tried swapping electrical from my 05 & nothing. Bike is an 04 crf250r
I also have the same issue with a 2010 CRF 250R, I’ve replaced everything, including the ECU.
I’ve got the same problem as you, so far I’ve done a tp sensor, ecu, wiring harness, map sensor, fuel injector, check timing and valve clearances, fuel pump and regulator rectifier yet the thing still won’t run at a steady idle and is running so rich
Post a reply to: CRF250R No start!