New yzfs250 blaster pipe and radiator questions. HELP

[sicivicdude]

As long as you make the cut perfectly perpendicular to the pipe and "rotate" it, you aren't changing the length or the tune.

If you begin to make cuts that aren't perfectly perpendicular (even though all you're doing is "rotating" it) you are changing the way the pipe expands (or contracts) so even though it didn't get any shorter or longer, you can change the tune some. So just be careful hacking up the pipe too much or be prepared to hack it back up after you get done with the project to get back some of that power.

I like the look of the YZF radiator like 3 wheeler rider did his. MacDizzy used two side by side radiators on the DT build but they kinda hung out each side like dumbo's ears. I didn't really like the look of the two radiators...

 

[brandoz28]

i like this radiator setup

 

[sheeblast]

is that a 450?????? and that is what the ones that said use two were trying to tell him. that is very good looking.

 

[brandoz28]

its a yz250f motor in the little blasty frame


redline (member on here) built it

 

[sheeblast]

link did work. who did this swap?

 

[brandoz28]

redline, the links are messed up because percent signs aren't working anymore

 

[sheeblast]

is there a thread about it anywhere?

 

[brandoz28]

here, and with a working link
http://www.blasterforum.com/engine-mods-swaps-129/yfz250-blaster-25012/

 

[sicivicdude]

I like the factory kind of look to the shrouds and all with the yfz250F but I don't like how the radiators themselves hang out each side. You look at it straight from the front and it looks like dumbo's ears sitting out there.

Contrast that with 3 wheeler riders YZF450 radiator that just about fits inside the frame... His thread's pictures aren't working either but it was about page 8 where he had the radiator mocked up and even with the shroud in place it barely hung out past the frame. I think it's a clean enough installation to warrant finding a radiator like that to tuck in there.

 

[YZ Otis]

I measured my predator radiator and it looks like it would be a good fit. I'd try one but the fill cap's on the opposite side from my Mojave and I'd have to get another front fender set. They're usually pretty cheap on eBay. You shouldn't have a heating problem on the "89" unless you raise the compression & try to squeeze a bunch more out of it. I use 12/40 sprockets. I use the WR gear set so it will be different for you. The WR has a lower 1st & a higher 5th.
Gear Ratios
---- Blaster --------- 89 WR250 -------- 90 YZ250 -
1st 34/11 (3.091) -- 32/14 (2.285) -- 31/15 (2.067)
2nd 31/14 (2.214) -- 29/17 (1.706) -- 29/17 (1.706)
3rd 25/15 (1.667) -- 24/18 (1.333) -- 22/16 (1.375)
4th 20/16 (1.250) -- 21/20 (1.050) -- 22/19 (1.158)
5th 19/18 (1.056) -- 21/25 (0.840) -- 23/23 (1.000)
6th 19/21 (0.905) ------ N/A ----------- N/A -----
The YZ will pull 14/40's in the power band and haul a$$ but it's zippin right along at idle and not so good for tight trails. Also you might find it pretty flat when it starts to fall out of the power band. That's a problem with dirt bike gearing. Everyone will want to know how fast it goes but to me that doesn't have much to do with how useful the bike is. It'll be plenty quick!
I use the WR stator. I use a yz cdi and run the yellow wire to the blaster rectifier for the light system. I think I used the YZ blk/wht to the on/off & key switch.
The pipe will be fun & there's a lot of experts on here to tell ya how to do it...LOL
Mine's an old build & folks have figured out a lot better ways to do this.
Lookin forward to watchin your build!
Good Luck, do it the way you want it done & never, never, never, ever give up ....burp!

BTW: Old Blaster suspension & brakes are inadequate for 45hp...IMHO

 

[3 Wh33l3r Rid3r]

I measured my predator radiator and it looks like it would be a good fit. I'd try one but the fill cap's on the opposite side from my Mojave and I'd have to get another front fender set. They're usually pretty cheap on eBay. You shouldn't have a heating problem on the "89" unless you raise the compression & try to squeeze a bunch more out of it. I use 12/40 sprockets. I use the WR gear set so it will be different for you. The WR has a lower 1st & a higher 5th.
Gear Ratios
---- Blaster --------- 89 WR250 -------- 90 YZ250 -
1st 34/11 (3.091) -- 32/14 (2.285) -- 31/15 (2.067)
2nd 31/14 (2.214) -- 29/17 (1.706) -- 29/17 (1.706)
3rd 25/15 (1.667) -- 24/18 (1.333) -- 22/16 (1.375)
4th 20/16 (1.250) -- 21/20 (1.050) -- 22/19 (1.158)
5th 19/18 (1.056) -- 21/25 (0.840) -- 23/23 (1.000)
6th 19/21 (0.905) ------ N/A ----------- N/A -----
The YZ will pull 14/40's in the power band and haul a$$ but it's zippin right along at idle and not so good for tight trails. Also you might find it pretty flat when it starts to fall out of the power band. That's a problem with dirt bike gearing. Everyone will want to know how fast it goes but to me that doesn't have much to do with how useful the bike is. It'll be plenty quick!
I use the WR stator. I use a yz cdi and run the yellow wire to the blaster rectifier for the light system. I think I used the YZ blk/wht to the on/off & key switch.
The pipe will be fun & there's a lot of experts on here to tell ya how to do it...LOL
Mine's an old build & folks have figured out a lot better ways to do this.
Lookin forward to watchin your build!
Good Luck, do it the way you want it done & never, never, never, ever give up ....burp!

BTW: Old Blaster suspension & brakes are inadequate for 45hp...IMHO

truiest words ever spoke.....but then again blaster suspension doesnt handle 16hp very well either hahahahahahahaha.

 

[rustyrat]

Wow... well the build is pretty much done... well as far as the motor goes haha.. thank you for all the info it was helpful. I ended up just using one radiator from the yz and mounted it behind the steering stem and made shrouds around it so the air had to go through it, I will see how the overheating situation is, i think ill be alright seing as how its a stock motor. The pipe came out great and the bike seems to run real good still.. i got the brakes all tuned up and the fronts are great but the rears leave something to be desired lol. Ill beat up on the suspension tomorrow and find out how bad it really is hahaha. BUt for now im happy with how it turned out ill snap some pics tomorrow

 

[brandoz28]

pics pics pics pics pics pics pics lol