YZ Blaster project (long rambling post)
Feb 25, 2008 | 01:58 PM
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YZ Blaster project (long rambling post)
"89" YZ Blaster
My son has been riding Blasters for about 3 years and thinks he needs more power. The size suits our tight,steep mountain trails and it's light weight makes it easy for a youngster to yank back to the trail after errors in judgment. He would like a new hot rod quad but our budget can't handle the cost. ATV's for us is about learning & fun.
This project is an effort to add a little power and learn a little about making the wrong stuff work well enough to be proud of. This was not a bolt in conversion but was not real difficult.
I understand a Blaster isn't much to start with but that's what we have. This "89" is older than my son and probable doesn't deserve this kind of abuse.
It has works shocks & Warrior disks on front, + 4 in arm, ex400 shock & hyd disk on rear.
I've read lots of threads & posts on this conversion but didn't find much solid info. After doing this myself I think most folk that talk about it really haven't done it. I'm sure everything I've done has been done before and take no credit for anything. I just want to share some of the things I ran into.
We race yz250's in our outlaw kart so we have some spare parts around.
We used a wr250 stator & gear set. The wr stator has a charging coil like the blaster so we could power the lights. The wr gears have higher 4th & 5th gears than the yz. 5th is actually an overdrive. Thought this would be good for the long beaches at the dunes.
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 YZ250 fits easily. Plenty of room. We cut off the blaster motor mounts (not the swing arm mounts). Also cut off the front fender support mounts. The rear boss that the swing arm bolt goes through is wider on the YZ than the Blaster. We cut off the right side swing arm tube to fit the YZ. You can drive out the brass bushing & seal then replace them after the cut. Better yet this is a great time to replace all the swing arm bearings & seals. Once the swing arm is sized you can place the motor in the frame to figure out the motor mounts, locate radiator mounts and build a pipe. We used cardboard to make motor mount templates, cut them out of scrap 1/8 in. steel plate, bolted them to motor and tacked them into place. The $20 e-bay FMF pipe was cut in 2 places, ground to fit & rewelded. The pipe must be installed in frame before installing motor in our case. Welding up motor mounts & pipe meant putting the motor in and taking it out several times to adjust and be sure everything fit with a bit of clearance.
We used a Kawasaki Mojave radiator. These are cheap and easy to find on e-bay. We welded 2 pieces of angle iron to the top frame tubes and a piece of angle iron across the down tubes. The only clearance problems might come from the pipe you chose and how it is fit. The FMF we welded up cleared by 1/4 in.
Motor mounts, swing arm mod, pipe & radiator mounts are biggies. Everything else just takes a bunch of fiddling.
No room for front fender mounts with YZ pipe so fenders are now race cut. Right one also has a hole for radiator fill cap.
Haven't got the gearing right yet. Blaster 13 x 40 is way too high. Now 12 x 40 and still too high. Will try 12 x 46 next. Can't go any smaller on the front so we'll work on rear.
The stock lighting works with the wr stator but there are no lights in the picture. I'll post a pic when we put the late model hood & light on. Old light is ugly according to the kid.
This thing is pretty quick. With a little lower gears it should handle trails and still be fun at the dunes. Might even suprise a few bigger machines.
If anyone's interested we'll report back when we get the gearing right and a little time on the sand. This was a fun project and wasn't meant to to be a fancy show bike. More like a junk yard dawg.
I should mention that the YZ250 has no counter balance so it vibrates a bit. Not good for me but it doesn't bother the kid.
Sorry for rambling, not too good at writing either!
Photos at:
http://s26.photobucket.com/alb...tickerOtis/YZ%20Otis/
YZ Otis
My son has been riding Blasters for about 3 years and thinks he needs more power. The size suits our tight,steep mountain trails and it's light weight makes it easy for a youngster to yank back to the trail after errors in judgment. He would like a new hot rod quad but our budget can't handle the cost. ATV's for us is about learning & fun.
This project is an effort to add a little power and learn a little about making the wrong stuff work well enough to be proud of. This was not a bolt in conversion but was not real difficult.
I understand a Blaster isn't much to start with but that's what we have. This "89" is older than my son and probable doesn't deserve this kind of abuse.
It has works shocks & Warrior disks on front, + 4 in arm, ex400 shock & hyd disk on rear.
I've read lots of threads & posts on this conversion but didn't find much solid info. After doing this myself I think most folk that talk about it really haven't done it. I'm sure everything I've done has been done before and take no credit for anything. I just want to share some of the things I ran into.
We race yz250's in our outlaw kart so we have some spare parts around.
We used a wr250 stator & gear set. The wr stator has a charging coil like the blaster so we could power the lights. The wr gears have higher 4th & 5th gears than the yz. 5th is actually an overdrive. Thought this would be good for the long beaches at the dunes.
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 YZ250 fits easily. Plenty of room. We cut off the blaster motor mounts (not the swing arm mounts). Also cut off the front fender support mounts. The rear boss that the swing arm bolt goes through is wider on the YZ than the Blaster. We cut off the right side swing arm tube to fit the YZ. You can drive out the brass bushing & seal then replace them after the cut. Better yet this is a great time to replace all the swing arm bearings & seals. Once the swing arm is sized you can place the motor in the frame to figure out the motor mounts, locate radiator mounts and build a pipe. We used cardboard to make motor mount templates, cut them out of scrap 1/8 in. steel plate, bolted them to motor and tacked them into place. The $20 e-bay FMF pipe was cut in 2 places, ground to fit & rewelded. The pipe must be installed in frame before installing motor in our case. Welding up motor mounts & pipe meant putting the motor in and taking it out several times to adjust and be sure everything fit with a bit of clearance.
We used a Kawasaki Mojave radiator. These are cheap and easy to find on e-bay. We welded 2 pieces of angle iron to the top frame tubes and a piece of angle iron across the down tubes. The only clearance problems might come from the pipe you chose and how it is fit. The FMF we welded up cleared by 1/4 in.
Motor mounts, swing arm mod, pipe & radiator mounts are biggies. Everything else just takes a bunch of fiddling.
No room for front fender mounts with YZ pipe so fenders are now race cut. Right one also has a hole for radiator fill cap.
Haven't got the gearing right yet. Blaster 13 x 40 is way too high. Now 12 x 40 and still too high. Will try 12 x 46 next. Can't go any smaller on the front so we'll work on rear.
The stock lighting works with the wr stator but there are no lights in the picture. I'll post a pic when we put the late model hood & light on. Old light is ugly according to the kid.
This thing is pretty quick. With a little lower gears it should handle trails and still be fun at the dunes. Might even suprise a few bigger machines.
If anyone's interested we'll report back when we get the gearing right and a little time on the sand. This was a fun project and wasn't meant to to be a fancy show bike. More like a junk yard dawg.
I should mention that the YZ250 has no counter balance so it vibrates a bit. Not good for me but it doesn't bother the kid.
Sorry for rambling, not too good at writing either!
Photos at:
http://s26.photobucket.com/alb...tickerOtis/YZ%20Otis/
YZ Otis
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