Otis' Hot Rod Blaster build

YZ Otis

Member
Sep 24, 2007
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Oregon coast
Otis' Hot Rod Blaster
It began as a 89 Blaster. We've owned it about 20 yrs. Played with brakes, suspension & engine stuff from the start. Put a YZ250WR engine in it around 07. Bf BOTM August 09. Switched to methanol at some point. That was entertaining. Took it apart to reconfigure the suspension and never got around to finishing it. Bare frame hung on the tap room wall for years with all front suspension mounts cut off as a constant reminder. I'm gettin pretty old so figured I could part it or put it together one more time. So here ya go, lol ... Burpp!
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"1989 Blaster"

Goal = Fun to build, fun to look at, fun to BS about and really fun to ride.
Inspired & encouraged by my Friends at Blasterforum.com & E2S

Otis' YZFS 250+ Blaster build
"1989 Blaster"
> Remains of Original plastics
> Fresh 1989 YZ250WR engine (wide ratio trans)
> Ohlins 360 kit w/additional porting to Ohlins' specs. ( Cylinder replated by Millennium Technologies )
> Crank rebuilt, weight added & balanced by Crank Works
> 89 Mikuni VM38 round slide ( bored to 39.25mm )
> Engine isolated from frame on magic rubber pads ( impossible, right! )
> 89 YZ250 Pro Circuit Pipe & Spark Arrestor
> 12/50 sprocket set
> CR250 anti-vibe bar mounts
> Fox Podium shocks
> A-arms +5 1/4" -.5" (actually out 2.625" and 1" in toward bike centerline by relocating a-arm mounts) each a-arm extended 3 5/8" and moved to rear 1/2".
> New A-arm bushings, seal caps, ball joints, tie rod ends and wheel bearings.
> +4 1/2" swingarm, eccentric carrier chain adjust. ( long travel, built for Fox shock length & travel )
> Amp Link chain guide ( negative reviews but I wanna try it at the dunes for awhile )
> Hand lever brakes all 3 disks & foot brakes rear only. Dual calipers on rear rotor.
> 12v battery, rewound lighting coil & TrailTech rectifier/regulator
> Headlight, tail & brake lights are led.
> Radiator fan
> ( *DIMWIT ) Stainless Bumper, tow ring, Grab bar & Heal guards.
> Silly fun stuff :)
Low fuel warning light, volt meter, usb charging ports, coolant temp guage, a really loud horn and Yamaha hubcaps!
* (Did It Myself With Inferior Tools)

No hurry .. finishing up the motor mounts while waiting for the crank to get back. Nothing pretty about it yet. It's just a bare frame so ya prolly don't need pictures
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Set some parts together to check clearances and finalize exhaust, rezzi & expansion tank locations. Lotsa final welds & cleanup to do before paint.
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Came across this old thread.
Can hardly believe it took me 13yrs to save enough $mall change to send the 360 cylinder & crank to the pros 🤣😂 ..
Most of the diy parts on this build where made over 10 yrs ago. Another old thread.

Anyhow, welding's done & got some paint on the frame to keep the rust away.

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Came across this old thread.
Can hardly believe it took me 13yrs to save enough $mall change to send the 360 cylinder & crank to the pros 🤣😂 ..
Most of the diy parts on this build where made over 10 yrs ago. Another old thread.

Anyhow, welding's done & got some paint on the frame to keep the rust away.

View attachment 36038
Couple of questions Otis. First off this is badass but I thought you got your yz swap blaster running a while ago?? Like a long f*cking time ago😂. Or is this just a refresh?

Anyway, Im curious what you did with the exhaust, or did it just fit? If you modified the expansion chamber then you just have a big bore dog with no power but I didn’t think it would fit without modifications? If it did just bolt up, what pipe are you running?


Also those bike motors have a mount on the head. Did you not put a mount there or did you weld up a mount for it right there?


Also super curious on the travel of this thing. Looks badass.


I plan on getting a long travel 450r dual rate elka for the rear end of the yfs250r when I get that far along and just cutting the shock mount and moving it back for more travel and down for a longer shock as well as lowering the rear end (I like a quad with a high front and low rear end, like the trx250r)

Also on a blaster Facebook group I did encounter a guy who has a rear linkeage suspension that phragle apparently built him back in the day. Something to think about.

Nice build!
 
Yes you can call this a refresh. My son rode it almost daily for a few years.
Devinjump.JPG


I put this methanol carb on and it got scary.

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Useless on trails. Exciting but dangerous at the dunes where you could open it up. Stock front suspension had to go so I cut off all a-arm mounts. Sat around in pieces for a long f*ucking time. Was gonna dump the Blaster stuff but I really want to hear those 360cc's sing. Hope this thread leads to that.

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If I was to modify an expansion chamber it doesn't mean I would have a big bore dog. If it it didn't work (and it will work) I would build one. I usually do things wrong but it's fun and I learn more than talkin bout it. Here's a link to an adventure a few years ago. Had fun & put it back to stock before the Granddaughter ever rode it. (Boring)


Ya, this build will have decent travel. Our old guest Blaster has close 12" in back, a hand me down from the YZ bike.

20180724_154027.jpg


I wanted to rake the front suspension back like the trx250r but it became to complicated. Will still be a sound platform for the 360.
Oh, never used the headstay on the kart or quad.
 
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Yeah, head stays are a debated topic in the 250R world as well. Many TRX guys don't run em, particularly with big bore cylinders.