Honda CR500???

[ghawkman]

What is the best year of the CR500 motor and why?

I have decided to put the CR500 motor in my 400EX frame. I already spent $2,000 on the suspension plus the pipe and everything else.

This bike will be the king of the hill!!!

I am thinking maybe 1987, 88, or 89 motor but not sure???

Also what is the power valve and is it a good thing??

Thanks...

[2fastandfurious]

Pretty sure the power valve "opens" when you get to a certian RPM range. Not sure on that though. That quad with be king. Very true. I would go with an 89. Specialy on 2 stroke....unless ur gonna redo the whole thing. 89 is a good year for a lot of motor devices. maybe its just a lucky year! :D

[rippin250r]

whats up? i did a 92 250x with a 89 cr500 motor. i built the bike last year. it had durablue axle,works suspension,250r arms,and other stuff. one problem i found was the bike had a lot of vibration from the motor,other than that i could take any hill,roost everyone behind me, i will say it was worth all the work i did. i think the bike was very unstable,jumping wise,other than that it was a great,unique project that took some time but well worth it. go for it. you would never believed the looks i got with the whip. people were shocked.

[86atc250r]

All the liquid cooled CR500's are basically the same. Some of the earlier years developed more power than the later ones because of their stock configurations, but the engines were essentially the same (porting and exhaust changes), so if you plan on building it, it doesn't really matter what year you use.

No CR500's were equipped with powervalves. KX500's did have though - but I've heard that the KX engine is worse about vibration and not as easy or cheap to come up with.

[AndrewRRR]

I hope you have a back-up bike to ride when your fillings get shook lose on your CR500EX. lol!
I have heard the 86 CR500 is the king of the hill when it comes to peak power and a scary powerband. It probably doesn't matter what year you get if you are going to get it ported, which I would do if you are going through this much trouble to make a hillshooter.
You might want to look into gusseting your frame. I have heard stories of frame cracks from vibrations and torque of a motor that big.

[Extremeracer167]

250X frame with a CR500 motor in it:huh i wanna see pics of that

The early 90s CR500s owned (92,93 especially, and 94). All years are very similar though.. Make sure you rubbermount the motor or it will shake itself to pieces.

[BlazingYamahaYz]

is about right with the power valve...power valves supposedly are supposed to open when u hit a certain rpm's, so at low rpms it is supposed to be closed, to prevent all exhaust from escaping, thus resulting in little to no power loss when u take off......something like that i had to get my powervalve replaced last summer...the mechanic wasnt 100% clear, i guess it mighta been since he had a beer or two before i got there:rolleyes:

[86atc250r]

In a 2 stroke the height of the exhaust port drastically affects the powerband - much like changing a cam on a 4 stroke, but with even a more dramatic effect.

A powervalve alters the exhaust port timing on the fly in attempt to give you more power everywhere without as many compromises as a non-powervalve engine.

Typically a powervalve engine will have more bottom end and less of a "hit" but more overall power.

[AndrewRRR]

If it's a drag bike a power valve won't really help you at all. The powervalve acts like variable exhaust timing (porting) but if it's a drag bike you spend all your time at WFO anyway. I don't know if they CR500's had powervalves. I don't think they did. Engines that big don't have any problem with torque down low!