Help with 2003 crf450 motoxbike?

Question

hi, im prepairing my bike 4 weston beach race, i had a rattle noise in engine, so i changed all the engine bearings, but i still have the noise, but now my exhaust is glowing red hot, can anyone help?

thanx

Answer 1

the glowing red is normal for a fourstroke mx bike.although they are not ment to be at idle for very long or they will overheat and loose coolant.i bet it glows when you are sitting still and goes away when you start riding.i promise this is normal.the engine rattle could be a couple of things.first have you ever checked your valves and are they in spec?second what kind of oil are you running in it? also honda is different from the other bikes like yamaha for example in they do not share there engine oil with the transmission.meaning there is less oil for engine lubrication.a good place for bike advaise is thumpertalk.com alot of great info.

Answer 2

the 2002-2004 Honda CRF450R's are known for exsessive engine noise....Check the specs on the valves, and chech the clutch..... my clutch makes a ratling noise when its idling, but goes away while riding.

as far as the glowing headpipe, thats normal and you have nothing to worry about there......

Answer 3

The rattling noise could be pre-ignition due to hot spots in the combustion chamber.

A lean mixture will create hot spots and cause the exhaust to glow red hot.

Check the "hot start" choke on the carb.

If it's stuck open, the mixture will be constantly lean, producing your bikes symptoms.

The choke plunger could be gummed up and stuck open, or damaged and stuck open.

Fully inspect the carb and intake manifold.