Honda CR500 motor question?

[ghawkman]

I want to put a Honda CR 500 motor in my 400EX frame.

Any advice as to what year motor, any mods if necessary?

People tell me that it vibrates like a M$#@%cker. Does it?

Can I mount it on hard rubber engine mounts and do some mods to help the vibration if this is true?

Thanks....

[TRX300X]

85 or 86 are the best year engines to use, after that they detuned them. As far as mods go, a pipe, set of reeds, and a crab should be more then enough. I have an '89 CR500 sitting in the garage that I just got done rebuilding for a friend and the power is insane. Even in the bike chassis they vibrate a lot and are extremely hard starting. Vibratin will be an issue, i'd do rubber mounts and fill your handlebars with silicone and see if you can't get an anti-vibe steering stem. Other then that you'll have to live with all the vibration.

[AndrewRRR]

Originally posted by ghawkman
I want to put a Honda CR 500 motor in my 400EX frame.

Any advice as to what year motor, any mods if necessary?

People tell me that it vibrates like a M$#@%cker. Does it?

Can I mount it on hard rubber engine mounts and do some mods to help the vibration if this is true?

Thanks....

Yeah I hope you have a good dental plan cuz it'll rattle you teeth out, even if you rubber mount the motor.

[NoWingNoPrayer]

LOL do you really need that much power?

[ghawkman]

What about a KX500 motor. IS that better? People tell me that this one has a counter balancer.. True???

[AndrewRRR]

Originally posted by ghawkman
What about a KX500 motor. IS that better? People tell me that this one has a counter balancer.. True???

I don't think any of the 2 stroke bike motors have counterbalancers. You might just want to use a quad motor. It's really not that hard to get CR500 power levels out of a 250r motor. Or since you are gonna have to make motor mounts anyway, put a banshee motor in it, that would be unique.

[shaneb]

I have a question ???

Will you have any vibration problems with a cr500 in a 400ex frame ???

[d-14 rider 27]

im thinkin without rubber mounting, and proper gusseting, a cr500 is gonna blow a 400 ex frame to pieces, why dont you get a 250r, and get a psi setup, or pilot cylinder, or polaris cylinder, or cr500 cylinder, anything is possible with the right machine shop, ive always heard good things of the polandas (polaris) and the pilot top ends. or just do a crf450 like mine :D them have counter balancers.

[YZROOSTINYA]

there is a 400ex with a cr motor on it on ebay right now

yes it will vibrate like crazy but it can be done

[433rd]

Originally posted by TRX300X
85 or 86 are the best year engines to use


Do yourself a favor and ONLY use one from the 1990-2001 years. The earlier ones made in the 80's have many parts (including most of the transmission) that are no longer available. As far as power compared to the 80's engine, mill the head a little, mild port work and it will smoke Any stock CR500, any year.

As far as vibration, yes there is some but many folks have created a "vibration legend" about the CR500 engines. Will you feel it more than the 400EX engine...sure...will it rattle your teeth out or vibrate you hands off...far from it. Most of the vibration you will feel in your feet at the pegs. Nothing more....nothing less.

With a few (very few) mods...running on gas...it will easily put out 70+ HP. They are a heck of an engine and one of the easiest of the "waterpumpers" to work on. They are also quite a bit lighter than any of the 4 strokes in the 400-450 class. Less weight= free power...


Go for it....

[Predator36]

Originally posted by shaneb
I have a question ???

Will you have any vibration problems with a cr500 in a 400ex frame ???

I have riden several conversions with CR500 motors in them. The 85-86 will make more power stock. If any engine work is done the later ones can make as much power as the earlier ones.

Vibration - sitting still it vibrates like mad and no this is no Myth. If you are riding it any place other than in the sand dunes, you will not feel the vibration - you have other things on your mind(missing trees and hanging on). The vibration in the dunes can be annoying. The only real bad part is what the vibration does to every part on the bike. Carry spare bolts and a welder.
.

[Predator36]

Anyone remember Mark Leager's twin engine quad with CR480 engines in it?? That had to be a fun ride.