cr 500 in a 400ex frame??

[sandspanker]

asking for a friend.... is ther anyone out there that has made the CR 500 conversion. I tell him the frame will crack from the vibration of the 500 two stroke motor.......even if it gets rubber mounted! anyone who has possibly done this conversion. PLEASE REPLY!!!!!! dont want to look like a jack *** in front of my other friends...

[bmw500hp]

Bud Matt Wrights cr500/250r conversion. Look cool enough for ya!

AHH NO pic wont work!

what a tease!

[bmw500hp]

Lets try again!!

[bmw500hp]

r frame however

[AndrewRRR]

Originally posted by bmw500hp
Lets try again!!

Wow, looks like someone got really exited looking at that bike ;)

[ZSK]

I'd be just as excited looking at that thing damn!!! Nice looking.

[hondarider2006]

damn that thing is nice:eek2:

[Quadzilla]

Is that a 400EX frame that the CR500 motor is sitting in? Does not look like a stock frame that's been modified to me.

[nacs400ex]

Originally posted by Quadzilla
Is that a 400EX frame that the CR500 motor is sitting in? Does not look like a stock frame that's been modified to me.

Looks like a heavily gussetted stock 250r frame to me, because of the square tubing and just where the frame rails are. How often does he crack the frame on that thing?

[YZROOSTINYA]

why doesnt he just do a big bore power valved 250r motor????

The CR engines have no counter balancer, thats the biggest problem.

[Matt Wright]

It is my 500 In the pics thanks for the good words. I picked this moter up for $300 bucks that is a lot cheaper than a big bore for the same power. The bike has a very smooh hit and pulls from bottom to top unlike a 330 big bore. As of today the frame has not cracked, It does vibrate but ITS WORTH IT!!!!!!

[brokedown]

WHat is it ? a 400 EX frame or a 250 R frame, I am thinking about putting a yz426 or a 450crf in my 400 ex and I am wondering which would be easier.

[wilkin250r]

I've heard of lots of problems with the CR500 conversion, mainly due to vibration. Every person I've talked to that has actually done it said it was VERY fast, very powerful, and also an absolute nightmare for anything but a drag race. Cracking motor mounts and numb hands.

[AndrewRRR]

Originally posted by brokedown
WHat is it ? a 400 EX frame or a 250 R frame, I am thinking about putting a yz426 or a 450crf in my 400 ex and I am wondering which would be easier.

Square tubing, gotta be an R.
I'd go with a 450. They are both gonna take about the same work, go with the one that has more potential and power.

[Matt Wright]

If you make good moter mounts they wont crack..................... P.S. ........you can balance the cr500 moter they use this moter in other forms of racing. Look up QRC KARTS must see!!!!!!!!!!

[AndrewRRR]

Originally posted by Matt Wright
If you make good moter mounts they wont crack..................... P.S. ........you can balance the cr500 moter they use this moter in other forms of racing. Look up QRC KARTS must see!!!!!!!!!!

I didn't know you could counterbalance those motors since the balance shaft is integrated into the design of the motor.

[Chef]

Originally posted by AndrewRRR
I didn't know you could counterbalance those motors since the balance shaft is integrated into the design of the motor.

You would need new cases to do this. Besides, I think he was talking about just basically balancing the crank and all the rotating stuff to cut down on some vibes.

Or, you could just do a PSI425R motor, and get a ton more HP than the CR500 conversion and not nearly the vibrations...

[AndrewRRR]

And MAC racing does a CR500 topend on a 250r bottom end. Those options are getting pricey though. Most people who put a CR500 motor in a R/EX frame do it because it's cheap and fast (although not when you factor in the dental work from shaking your teeth out).

[Out_Sider]

i heard that the kx500 conversion is easier and not as hard on the frame? can anyone fill me in on this?