Project YSF250r is a go! A Baja built yz250 swapped blaster.

Blaster200_117

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May 11, 2024
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After much research I be decided to go ahead with project YSF250r

I will be selling trx450 as soon as it’s fixed and buying a blaster. I am waiting until winter to fully start the build which will give me plenty of time to track down a cheap blaster rolling chassis or one with a blown motor in my area. Also will give my plenty of time to plan out the build better. I will also be selling my z400 to contribute to the build and buy a 250 bike I can ride around in the meantime (bikes are way cheaper than quads in my area).

Project YSF250r is making the blaster how it should’ve been back in the day. A trx and LT 250r competitor. In the front I will be running +3 up 1 an arms with an 18.25 inch shock (+4 up 1 if I can find some used ones. They don’t make them anymore). I’ll be running banshee spindles and brakes. I’ll be running a +3 axle. The goal is around 48 inches wide. I’m still not sure how I am going to get the extra 2 inches.

As for the rear I plan on running a +3 or +4 swing arm. I’m not sure which one as iv heard a +3 swinger with up 1 arms puts the foot pegs centered in the wheelbase which makes for a desirable handling and weight distribution. However with a +4 I get slightly more travel as extending something out naturally gives more travel. As far as a true long travel rear end is concerned I’m not sure how I am going to do it yet. As far as I know the only true long travel blaster was phragers which he won the Baja 1000 on and had 15 inches of travel.

I’d like to be able to at least get stock 450 travel out of the rear (more if possible) so if anyone has any ideas for that let me know.

as for suspension I plan on running triple rate 18.25 elka shocks in the front and dual rate elka in the rear.

The entire frame will be gusseted and powder coated.

I will also switch to hydro disc brakes in the front.

In the power department I will be putting a YZ250 motor in it. I will be on the hunt for a donor bike that I can pull motor, radiator, pipe, etc out of. I will sell the rolling chassis when done.

As for plastics I will run maier race fenders front and back unless I can find some nice project blaster fronts. I’m a very good fabricator and my goal is to fabricate some mounts and a system to attach the fenders to the seat for easy disassembly when working on it. Just like the trx250r had.

A desert tank will be run for more fuel.

Bigger Aluminum wheels will also be installed for more tire options and weight savings.

The specs I hope to achieve out of this build are 48 inches wide, at least a 47 inch wheel base, if not longer, at least 9 inches of travel up front (stock is 7, stock trx450r is 8.5), and at least stock 450 travel in the rear (stock blaster is 7, I believe stock trx450 is 10).

I also would like to keep it under 330lbs (my old stock one came in at around 300lbs?)

If anyone has any input on anything let me know. Especially with increasing travel, specifically rear end travel. Also if anyone has experience motor swapping these let me know. I suspect the hardest part will be exhaust and radiator placement. Not to mention a yz250 motor is not balanced and I will need to make rubber grommeted mounts as to not vibrate everything loose.



So… why use a blaster chassis??? A couple reasons. #1 is I like the light weight feel of them which is even more prevalent on these quads than my dads trx250. #2 is price. Even a 250r rolling chassis (if you can find one) goes for 2k where I’m at. A running one is like 5k-8k depending on condition and mods. I can buy a running blaster in my area for 1200$ and iv seen non running ones for 400$. Not to mention the price of parts is way cheaper than a 250r… why… simply because it’s a blaster and not a 250r. #4 is the small frame. Small frame with big suspension is the goal for this. It creates a small feeling, lightweight machine, that has suspension as good as the bigger ones. And the final reason is I want to do something that hasn’t been done. A full yz250 swapped long travel build is yet to be done as far as my knowledge. There are plenty of Baja built 450 and 250r quads out there but I’m yet to see a blaster in person.


The end plan is to build the ultimate desert blaster.
 
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the Blaster that won the Baja 1000. And my inspiration.
 
Greetings. Looks like you've put a lot of thought into this project. I've had a yz Blaster for over 15yrs. All the swingarm geometry was from Phragle. My work is kinda diy funky but there's been some really nice hybrid Blasters built here. Should be in the archives. 12" rear travel is easy, the fronts a bit more challenging. Good luck!
I'll be watchin.

 
Greetings. Looks like you've put a lot of thought into this project. I've had a yz Blaster for over 15yrs. All the swingarm geometry was from Phragle. My work is kinda diy funky but there's been some really nice hybrid Blasters built here. Should be in the archives. 12" rear travel is easy, the fronts a bit more challenging. Good luck!
I'll be watchin.

Thank you! Iv heard a +3 up 1 setup with 18.25 shocks here about 9.2 inches of travel. My goal is to beat my stock trx450 travel. Then it’s a 330lb machine with more travel and 40lbs lighter… the ultimate Baja rig.

What happened to phragle. He just kinda disappeared huh?
 
Greetings. Looks like you've put a lot of thought into this project. I've had a yz Blaster for over 15yrs. All the swingarm geometry was from Phragle. My work is kinda diy funky but there's been some really nice hybrid Blasters built here. Should be in the archives. 12" rear travel is easy, the fronts a bit more challenging. Good luck!
I'll be watchin.

Nice dude. Clicked through all of that thread and it looks like you beat me to the punch with a long travel yz swap.

I wonder if I could get even more travel out of it using a yfz450 rear shock… I don’t understand rear suspension of these that much. I’m used to linkeage setups where you just buy a long travel rear link and new shock for long travel. I’m assuming you move the shock mount location on the swing arm down for a longer shock?

iv also thought about trying to build a lineage setup for these… more control over your travel, easier long travel, leverage ratio control, etc.
 
I think I'm in your desired travel range now. Prolly get another inch when I rebuild the shocks & take the spacer out. They're like new now and hate to waste the rebuild kit. The arms are 3 5/8" longer but 1" is towards the bike centerline so only 2 5/8" longer than oem.
20240514_075547.jpg


Secret anti-vibe motor mounts. No continuity between engine & frame if the plug from stator to cdi & coil is disconnected. That can't work, right 😂
20240427_161859.jpg
 
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I think I'm in your desired travel range now. Prolly get another inch when I rebuild the shocks & take the spacer out. They're like new now and hate to waste the rebuild kit. The arms are 3 5/8" longer but 1" is towards the bike centerline so only 2 5/8" longer than oem.
View attachment 35974

Secret anti-vibe motor mounts. No continuity between engine & frame if the plug from stator to cdi & coil is disconnected. That can't work, right 😂
View attachment 35975
Looks awesome. I’ll definitely have some more questions for you when I find a donor bike and blasted chassis about yz swaps and suspension.

How do you think your front travel on that compares to fireball racing long travel +3 up one arms that use a 18.25 shock. Just wondering if I should try and make my own arms like you did or just buy some bolt on long travel arms.