Question about 2003 Honda CRF 450 R
Crf450 misfire high rpm@
Posted by Anonymous on
Hi, Anonymous and the usual suspects are:
1. Severely discharged or a damaged battery should have 12.5 volts or more and be able to pass a proper "LOAD" test if necessary, you may have a cursory reading of 12.5 volts or more but little or zero amperage the battery is faulty and must be replaced, AGM batteries fail in this scenario more so than lead-acid batteries.
2. Check battery terminals for damage or corrosion, check the battery cables at "BOTH" ends for loose, corroded, or broken connectors, "INSIDE" and outside the cable harness, perform connector wiggle test and check cables with an ohmmeter if necessary.
3. Spark plugs in bad condition or partially fouled.
4. Spark plug cables in bad condition and leaking check for spark leakage in the dark
5. Spark plug gap too close or too wide.
6. Faulty ignition coil, module, and or sensor.
7. Loose, dirty, or corroded ignition module connector at crankcase.
8. Faulty CKP or CMP, MAP, ETS, ATS, TPS, O2 sensor.
9. Dirty air filter.
10. Intake air leak.
11. Water, dirt, or rust in the fuel system.
12. Carburetor contaminated, sticky float, plugged jets.
13. Carburetor vacuum diaphragm torn, cracked, not seated or installed improperly.
14. Multiple carburetors out of sync.
15. Fuel filter clogged.
16. Old or contaminated fuel.
17. Fuel tank vent system plugged or carb vent line closed off.
18. Gas cap diaphragm valve faulty.
19. Vacuum line from intake manifold to fuel valve is broken, cracked, pinched, or missing.
20. Carburetor controls misadjusted.
21. Incorrect valve timing.
22. Valve springs floating, weak, or broken.
23. Damaged intake or exhaust valve.
24. Incompatible performance parts.
25. Control module may be in "LIMP" mode
26. Check for engine trouble codes.
For more information about your issue and valuable "FREE" downloads that you will need for viewing or printing please click on the blue links below. Good luck and have a wonderful day.
crf450r Misfire totally stumped
Honda CRF450X 2005 Service Manual
Honda CRF450R Owner Manual
Posted on Oct 19, 2017
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Posted on Jan 02, 2017
You should not have oil leaking from the carby. If you have over filled it with oil, then it may be coming from the crankcase breather and then into the airbox, and appearing to come from the carby. If you have not over filled it, then the bike may have blowby problems with compression gasses passing the rings, and in a similar manner forcing oil out the crankcase breather. Not sure about the hole in the side of the cylinder... do you have a picture? Unless its pouring out, or gets worse, I would not be too worried. If you have over filled the oil, maybe time for an oil change to get the level right.
Posted on Dec 06, 2008
it sounds like your valve/rocker cover to spark plug tube seal is folded over or something. My reason for saying this is, because the only place for oil to get into the plug tube is a bad seal to the cover or the spark plug isn't tight? and that hole is for expelling liquid so it doesn't cook the plug into the head
Posted on Feb 19, 2009
Have the dealer replace the worn chain. On this new of a bike I think the chain may be okay. Ask the dealer if you are adjusting the chain properly.
Posted on Mar 12, 2009
SOURCE: Engine misfires at high rpm
Depending on how high the revs are, it is either valve bounce or an ignition fault. Check the plug type and gaps and check the engine mapping.
Posted on Jan 03, 2011
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