YZ250 motor mount experiment

[YZ Otis]

Been told this won't work so I gotta try. I can survive the embarrassment of failure I'm gonna isolate the motor with rubber. Kinda crude but I might learn something. I'll enlarge the hole in the cases for the swing arm bolt and install rubber bushings. I'll use rubber bushings at the other bolts also. That's what the little tubes are for. I'll update it as I go.

This is all because of Freek and his slick stator windows. I just had to have one for a YZ. In the process of trying to make one I found play in the main bearing on the stator side Since the motor had to come out I decided to play with the mounts. Props to Freek for his great ingenuity. Maybe someone can figure out how to trigger the LED's to strobe the flywheel and freeze a logo. I have it working for a bit but can't survive the big voltage swing from idle to 10,000 rpm. Kinda cool when it works.

We where gonna put our big bore YZ in this summer but this quad is already a lot of fun. We'll look for a roller to build a big bore YZ Blaster that's a little nicer than old Mr. Potato head here.

YZ Otis

 

[Blasterdude27]

The stator cover looks badass man! Can't wait for an update.

 

[Paulie B]

Can't believe peeps are letting this go by.
That's mighty fine fabbing you got goin on man.
I say do it, can only help IMO.
Worst thing I've heard about rubber mounting is cracked pipes
because of the extra movement of the motor.
IDK if a 250 would shake that much since they were 500 hybrids that had the pipe issues.
Worst case just also rubber mount your pipe mount like I did on the 4 hundy.
Keep us updated...

 

[L.T.]

Looks like a lot of work but keep us updated!

 

[YZ Otis]

couple more pix

Thanks PaulieB - Heard your Blasty is retiring to the trophy case to make room for the yellow/black Hannah Shee build. LOL

The pipe will be mounted to the motor except for 1 rubber mount at the grab bar.

Couple more pix. Don't have an inventory of different density rubber around so I use what I got. Inner tube The more rubber disks I compress into the tubes or case the firmer the mount becomes. Kinda like adjustable bushings! How's that for a BS sales pitch

Swing Arm bushing

I bored out the mount holes in the cases, just gotta put another crank & bearings in it before I put it back together.

YZ Otis

 

[2stroke4life]

badass man, and yea myne vibrates from hell lol

 

[YZ Otis]

Goin back together.

Swingarm mount

Since I cut a window in my flywheel cover I thought I might as well put a window in my piston while I had it out. Make it more interesting when it fires up again

 

[stephen12091985]

hows it run????????????????

 

[YZ Otis]

Well, it still ain't no Cadillac but realistically I didn't expect that. If you put you hand on the motor and then the frame there's a big difference. Sitting on the bike you can feel that high frequency vibration as it revs that you can see on the shifter in the vid. It's an improvement but not as much as I'd hoped for. Now I need to watch how it holds up and maybe try some different types of rubber.

 

[Blasterdude27]

Oh baby I wanna ride her

Nice job man.

 

[Paulie B]

That's a baby rattle!
You should see my bike shaking at full song- which is nothing to brag about.
On mine the rear shock compresses from the vibes.
From the looks of that vid we both share the same vibe range though,
interesting.
I've learned to let off the gas easy and it lessen the shakes on deceleration.
I love the clutch cover. YZ Blaster is my name on the Baja Forum.
I'm thinking about stealing a picture of it and using it as my avy over there
do you mind?

 

[YZ Otis]

YZ Blaster is my name on the Baja Forum.
I'm thinking about stealing a picture of it and using it as my avy over there
do you mind?

I'd be honored.

I'm sure the 250 doesn't shake anything like a 400. It's really not bad. I've raced karts with the 250 and with cr & kx 500's and there's no comparison. Course there's no comparison in power either.

 

[YZ Otis]

I'm gonna redefine my opinion here. Hell, since it's my thread I can do that. - Truth is I don't ride blasters very often. I built this one for my son and I test ride'm when I fix something that broke. I believe I had unrealistic expectations that it should be super smooth. I decided to take it on a little trail ride before I purged it. On the way back I realized this thing is a pretty nice little quad. I went and got out our guest Blaster and took it on the same ride. Surprise, surprise. It vibrates too. There is very little difference in the vibration you feel. We've been working on this thing so long I hadn't realized the progress we've made. I'd have to say that the difference in vibration between the 240 & the YZ is small and the difference in acceleration significant. So, I'm happy and ready to start building a better one

YZ Otis

 

[Paulie B]

That's a good realization.
Enjoy your creation.
Who wouldn't want a YZ250 Blaster?
Honestly a 240 kit would add enough mass to the piston that
I could believe it would be about the same in vibrations as your 250....

 

[liljatownboy]

 

[liljatownboy]

why did you delete your vid?

 

[sonsan95]

Great work man that's awsomeI:I That thing must be fun to ride.

 

[Brute71]

any updates? or a vid of it tearing it up?

 

[89custom]

that thing would be fun as hell to ride. whats more powerful, a yz250 or a lt250r engine? (trx 250r also?)

 

[blasterfreek30]

awesome job man....thanx for the props on the stator cover. urs looks badass