cr500 engine in 250r frame?

[bmw500hp]

A bud has a 250r frame, real nice setup! He's bent on putting a cr500 motor in it. Does anyone have any tips for this conversion or know of someone who has done it? He knows about the vibration but he doesn't give a chit. lol

thnx
mike :D

[stupid driver]

i know a guy that did it. That thing is a fast mofo. Just be sure to have some rubber mounts and you will be ok. the guy that did it did gusset his frame though. Better safe than sorry

[bradley300]

def gusset the frame, anti vibe steering stem, maybe even a houser wrist wrester, anything to absorb the vibes

[kgbg]

My tip is : Don;t do it. Its more just that it will be extremly uncomfortable to ride, the vibrations will literally shake the machine apart. My buddie has one. there is not enough runnber mounts in the world to stop the machine from breaking itself apart.

[rebound]

I wouldnt do it, my bud had the mac racing trx 500r and even with the counter balancer it was a handful and you couldnt ride it for more then a half hour without your hands going numb.:eek2:

dont do it.

it sounds like your bud needs someone who knows r's port that ***** to its fullest potential.

believe me there is a difference between port jobs....

[airheadedduner]

Originally posted by rebound
I wouldnt do it, my bud had the mac racing trx 500r and even with the counter balancer it was a handful and you couldnt ride it for more then a half hour without your hands going numb.:eek2:

dont do it.

it sounds like your bud needs someone who knows r's port that ***** to its fullest potential.

believe me there is a difference between port jobs....
The MAC TRX500R is not a CR 500 motor though. Only the clyinder grafted on an R bottom end. From what I understood vibration was not that bad if you made a head stay to work with it.

[bmw500hp]

hey guys.... I really appreciate the responses and I know (matt) my buddy will as well.

Whats up is the bud is more of of an (experimental) guy than a "whats best" type of person. He really likes the exotic stuff. I think he knows it's more or less a time bomb but he's got it in head he wants to feel that big blast!

Again :D Really appreciate the info and if anyone has anymore advice, especially technical, keep it comming...

I gotta say tho, hope I do get a few minutes of seat time on the bad boy :macho before detonation:eek:

[hondafox440]

I say go for it. Rubber mount it, torque the bolts down and use plenty of loctite. See my other thread for the ongoing "dirtbike engine vibration" debate :rolleyes:

[AndrewRRR]

If he wants to go exotic he could do like Trick racing here did and put a turbocharged banshee motor in a 250r :D
Won't shake the bike apart.

[300exQuadracer]

call up burgard cycle and talk to them, i have a buddy who got one from them allready built and he said it vibrated his teeth out i dunno if that much power would even be worth the vibration effects

[airheadedduner]

Originally posted by AndrewRRR
If he wants to go exotic he could do like Trick racing here did and put a turbocharged banshee motor in a 250r :D
Won't shake the bike apart.
Is that the quad that ran a 10.9 or something like that at woodburn:confused: Like 120-130mph :devil:

[AndrewRRR]

Originally posted by airheadedduner
Is that the quad that ran a 10.9 or something like that at woodburn:confused: Like 120-130mph :devil:

Yep

[wilkin250r]

Originally posted by bmw500hp
hey guys.... I really appreciate the responses and I know (matt) my buddy will as well.

Whats up is the bud is more of of an (experimental) guy than a "whats best" type of person. He really likes the exotic stuff. I think he knows it's more or less a time bomb but he's got it in head he wants to feel that big blast!


Well, if your buddy has money to throw away, then go ahead. My advise is, don't PC the frame, because the motor will vibrate the frame apart and he'll have to blast the PC off to weld the frame every week.

Tell him to make extra motor mounts, he's gonna need them.

[bmw500hp]

thanks again! well, I guess he's bought it, so looks like no turning back now! Kind of exciting though.....sounds like it could be a big hit at the county fair drags :D

[bmw500hp]

The cr500's in and looks bad arse! Couple of parts on order and shuuld be ready next saturday...this ought to be fun..:devil:

[DamageInc]

Originally posted by wilkin250r
Well, if your buddy has money to throw away, then go ahead. My advise is, don't PC the frame, because the motor will vibrate the frame apart and he'll have to blast the PC off to weld the frame every week.

Tell him to make extra motor mounts, he's gonna need them.

So why doesn't it vibrate cracks into the CR 500 frame?

[2ex1R]

A few years back I was with one of my buddies at his girl freinds house.He shows me her dad's "250r"I notice that it ain't no 250r motor.I didn't know what it was.It was a honda 2 stroke.Well her dad got home and he tells me it's a cr500 motor.The bike was a sand dragger.Ran low 5's in the 300ft.


He started for me.It did shake alot.But he said he never really rides it other than racing it.

I would rather have a 370 stroker motor or something.Even though I am not sure the stock R trans would hold up to that.


That guy had the original R motor sitting in the corner.I offered to buy it from him.But he wouldn't sell.

[nuclearkielbasa]

There are a couple of companies out there who may be able to blueprint and balance your friend's 500 motor. I would check with either FMF or ProCircuit Racing. Balancing makes a noticeable difference in a CR500 motorcycle, so I would think it would make a WORLD of difference in a quad frame.

[AndrewRRR]

Originally posted by nuclearkielbasa
There are a couple of companies out there who may be able to blueprint and balance your friend's 500 motor. I would check with either FMF or ProCircuit Racing. Balancing makes a noticeable difference in a CR500 motorcycle, so I would think it would make a WORLD of difference in a quad frame.

I wonder if adding flywheel weights would help also.

[exatak199]

Originally posted by DamageInc
So why doesn't it vibrate cracks into the CR 500 frame?

yaa you all are soo afraid of some vibration look at that CR125-250-500 no counter(sp) balancer or rubbermounts those things don't vibrate bad. bunch of ninneys :blah:

[4wheelboy]

Originally posted by exatak199
yaa you all are soo afraid of some vibration look at that CR125-250-500 no counter(sp) balancer or rubbermounts those things don't vibrate bad. bunch of ninneys :blah:

its alittle diferent in a quad frame:rolleyes:

[Diedrich]

yeah on a dirt bike the front forks soaks up most of the vibration..but i think its a good idea if hes got the money..i like building different quads too..maybe it wont be to bad

[Chef]

Originally posted by bmw500hp
A bud has a 250r frame, real nice setup! He's bent on putting a cr500 motor in it. Does anyone have any tips for this conversion or know of someone who has done it? He knows about the vibration but he doesn't give a chit. lol

thnx
mike :D

Tell your bud to buy my PSI 425 motor, and wave goodbye to all those CR500 conversions. The vibration out of mine isnt bad at all. :cool:

[DamageInc]

Originally posted by exatak199
yaa you all are soo afraid of some vibration look at that CR125-250-500 no counter(sp) balancer or rubbermounts those things don't vibrate bad. bunch of ninneys :blah:

They do vibrate quite a bit, but you're right that it's not unbearable. They wouldn't make them if it was. And you need to have steel shank boots on to kick the things over, but damn are they fun! I never owned one, but I have ridden the KX500 and CR500, and they are a rush! Some folks seem to be too paranoid about the vibration; the forks don't absorb the vibration on a bike any more than the front suspension on a quad does, and the vibration doesn't crack frames on them. Your hands tingle when you get done riding them, but so what, it's not like you go out touring all day on a machine like that!

[wilkin250r]

Originally posted by DamageInc
So why doesn't it vibrate cracks into the CR 500 frame?

Because the CR500 frame is designed to handle the vibration. The 250r frame isn't.

I'm not just talking out of my butt. I've known a few people that have done the CR500 conversion, not one of them has been happy with it. Yes, it's REALLY fast, but even with rubber mounts, they constantly had problems with the motor vibrating out of the frame.

One particular friend (the same one I bought my engine from) said it was the worst thing he's ever ridden, and wouldn't recomend it to anybody. He couldn't keep the motor in the frame.

[AndrewRRR]

Originally posted by wilkin250r
Because the CR500 frame is designed to handle the vibration. The 250r frame isn't.

I'm not just talking out of my butt. I've known a few people that have done the CR500 conversion, not one of them has been happy with it. Yes, it's REALLY fast, but even with rubber mounts, they constantly had problems with the motor vibrating out of the frame.

One particular friend (the same one I bought my engine from) said it was the worst thing he's ever ridden, and wouldn't recomend it to anybody. He couldn't keep the motor in the frame.

Same here. Everbody I've talked to who did it said it was horrible unless it's strictly a drag bike and ridden for 100yds at a time (your arms go numb, etc). There is a reason they put counterbalancers in quad motors. You can't compare how it vibrates in the bike chassis to how it will vibrate in the quad chassis, it's a whole different ballgame.