newbie, yz250 swap in unknown year blaster

[Metallica]

Hi, I'm charlie. I'm a gear head and usually I stick to things with three wheels, but I ended up bringing this home. I think it's a 97, butI'm not 100% sure
the plastics are perfect and apparently they're an after market brand called meiers




I've got everything except a motor for it, which i can get a stock 200 for 80$ but there's no fun in Stock. I can get a yz250 motor for roughly the same price, and I'd like to install that. I'll do a search on here to learn more about that. Also, what's this big weird thing on top of the carb?

I'm looking forward to learning. Charlie

 

[Fast6hand]

That's the TORS unit. It's a throttle override if the throttle was to get stuck. Everyone eliminates them due to them being faulty. Won't have to worry about it if your going to a different motor.

Blaster engines can be made stout with some basic upgrades. Pipe, port/polish, rechambered head to name a few.

 

[Metallica]

Alright, now when it comes to the head work would it be within reason to mill a few thousandths off the bottom of the head to gain a little compression? I've got a full machine shop, lathe, mill etc. Or for the simplicity, should i just buya new head?

 

[Metallica]

Power washed it off and it cleaned up very nicely

 

[Metallica]

Picked up a 2001 motor, foot peg and clutch cable today

new plastic nose too

All i need to do is put a helicoil in one head stud hole, and pick up some hardware to mount the foot pegs and motor. Then i have to locate a stinger for the exhaust. I found a nice red seat with no rips for 50$ too so I'll pick that up once I have the money.

 

[deeeebeeeeee]

When I was told that a blaster motor can make 30hp reliably with an aggressive trail port, rechambered head, and a matching pipe. I thought wow that's nice, when I got mine running, (I am guessing it makes between 25-30) I was like holy sh*t this thing runs like a real race bike. Thing is around 30 horse on a blaster is almost the same power to weight ratio as a stock banshee, except with a slightly closer trans ratio and typically smaller tires and lower gearing on the cog and sprocket.
When you take what is effectively the same power to weight ratio and only ask it to do 60 or 65 mph rather than 75 or 80mph, you end up with some pretty stout acceleration that is mostly limited by available traction thru 4th gear or so.

I have heard you can swap in a 6th gear set from a banshee, since it is a little higher gear and designed to pull fully across the band in 6th, where as the blasters top gear is much closer and only drops about half the rpm from 5th to 6th as the banshee gear. Wish I would have known this when I had my cases apart.

Anyhow good on you for the blaster project, if you watch how you spend your money and do the right mods, you can end up with a bike that will compete against any 450 off the showroom floor, for under $2000. I am at $1500 now and really only need better front shocks and to take care of a few visual details and I will have a bike that i can honestly say I would prefer over nearly anything 4-wheeler that sits in the showroom today. Of course I don't think you can buy a true sport quad in 2 stroke these days.

 

[Metallica]

I'm not really looking for too much of a hot rod, i mostly want something to ride on some trails that I won't end up hurting myself, right now other then my honda atc's all i have to ride is my dad's worked over 87 lt500 quadzilla, which me being only 120lbs is like a rocket ship and i never usually get the zilla out of 3rd or 4th gear. But the banshee gears fit in the blaster case? And also would a search on here turn up any instructional threads to doing some porting at home? I have a slight concept of it, but I'm definitely no expert

 

[deeeebeeeeee]

You need to go to the kenoconnorracing you tube channel has has some Invaluable, vids not only on blaster porting, and engine assembly, I also reccomend you watch his Banshee porting video series, before you even pick up a rotary tool.
I followed Ken's videos, done my own porting and had KOR do my bore and head rechamber. Altough I deviated from the porting video as far as cutting the port windows and timing, I ended up with a really sweet sounding motor that ran harder and made more power than I imagined, fortunately the extra power and compression from the head rechamber masked any low rpm power loss, from my less that ideal porting. The work I did in my cylinder is painfully detailed, in one of my threads, although I wouldn't follow my initial numbers, or final numbers, the sport port templates do a much better job of making clean, power across the board, even just following the video will give you better suited results.
Mine does ok on the trails and cruises all right, but for tight or hilly trails I find myself wishing I would have left a little more power down low.

For a trail bike I would at least rechamber the head and either 1 follow the vids and enjoy the extra hp, 2 get the sport port trail porting templates and make lots of good usable power, 3. Have Ken do the porting and rechamber, and enjoy the best power for your purposes.

Either way you go, you will probably want to run a low end pipe fmf fatty and dmc alien are fairly popular but about any low-mid pipe will work.

 

[Metallica]

I was pretty lucky and i ended up getting a pre ported jug with good studs plus this 300ex honda in a trade

the Honda runs great but the starters bad, so once i get the blaster together I'll work on that. But i did get the motor in the blaster, that was interesting to do alone.

I'm in the middle of removing the old jug to put the new one on. Then all I need to do is run to the hardware store to get some various hardware, and i could probably ride this thing today but i don't have a stinger for the exhaust.

 

[Bluesman]

I have heard you can swap in a 6th gear set from a banshee, since it is a little higher gear and designed to pull fully across the band in 6th, where as the blasters top gear is much closer and only drops about half the rpm from 5th to 6th as the banshee gear. Wish I would have known this when I had my cases apart.

There is no way any of the Banshee gears will fit in Blaster cases.

 

[deeeebeeeeee]

Wow that's awesome, I always liked the 300ex and 350 warrior era of quads, which includes the blaster and banshee of course.
But that is awesome with getting the pre-ported jug. Did the guy say what kind of porting was done and by whom?? I would probably map it or at least take some measurements from the deck of the cylinder to the top of the exhaust port, and to the top of the transfers, those measurements alone should give you an idea of what kind of porting was done, and what kind of power spread to expect.

Can you get some pics of the cylinder and ports for us??

There is no way any of the Banshee gears will fit in Blaster cases.

I will try to find the thread apperently someone seperate the shafts,removed the gear from each shaft that handles 6th, and replaced them with the gears from a banshee. For this or something similar to work: either the gears would have to have the same inner diameter and the shafts be spaced the same between the two quads, then you would have to change both the drive side and driven side gears. Or if the gears had the same inner diameter, and the difference in spacing was equal to say the difference in driven gear diameter, then the driven gear only could be swapped. I have never tore into a banshee nor have I had a look at the gears themselves seperate from the shaft.

I though about giving it a look, but the banshee's 19 or 21 tooth wheel gear for 6th is $50, and the other, i am sure is similarly priced.
So it's either find a blown banshee trans for cheap, or buy the gears themselves. I will see if I can find the thread, but yeah the idea isn't to try to swap out the gearshafts, but to replace only the gearsets that controls 6th. Can it be done?.. IDK supposedly it has been done, but?.?

http://www.yfzcentral.com/forum/37-tips-n-tricks/61974-easy-cheap-blaster-upgrades.html

A guy mentions it at the end of this thread, I saw it one more place as well.....trying to find it

 

[Metallica]

I probably should've measured the ports before i assembled it, because last night my friend and i attempted to start it and we both kicked on it for about 20 minuets and we never got more then 3 pops out of it, and he suggested that whoever did the porting might've went too far and messed it up. It's totally assembled now though, i got a stinger for 35$, i would attempt to just bump start it but this motor has a front sprocket that's one tooth bigger then the original one, so my chain doesn't fit.

Also the kick start return spring popped out of place, so I'll have to go in there and fix that. But i know I'm getting fuel, i have very good spark, and I'm not lacking compression so it should run. Either the porting was done wrong, or my carb just doesn't have big enough jets to get it to go.

I did score an aluminum cobra exhaust silencer for free the other day, and i adapted it to fit on the ex because it wasn't an exact fit. I used some 1 1/2 inch exhaust tubing off our 37 ford pickup to build an extension off the header to connect the pipe to it, and i found a piece of slightly smaller tubing that was a press fit into the 1 1/2 and that the cobra pipe end fit on, so now i can finally throw out that old cobbled together stock muffler that was on it. The pervious owner must've beat the baffle out with a screw driver or chisel, then the end broke off and when they rewelded it it was hitting the rubber line off the brake fluid reservoir and it melted that.


It's a little dented on the tapered part, but the baffle is perfect so I'm going to use it. When it's cold it shoots a 8 inch blue flame out the end!

 

[Metallica]

I tore into the motor to see why the kick start spring wasn't engaging and i found out why.

And what little bit of gear lube that came out of the drain plug looks like this

I didn't find the little broken off piece of spring anywhere under the cover, so what are the chances of it ending up falling into this hole?

Grrr. Just my luck. I'm not sure if someone might've been in here before and removed the broken piece, or if it's floating around in here waiting to ruin everything for me.

 

[speedyslyder]

120 psi is normal blaster compression check it.
that year has a 4 wire stator if the stator has 5 wires you need to ground the additional wire to the frame.
and if it does have 5 wires it is possible it is cheap stator of e-bay and that is why it is not starting.
timing has to be right/as a sheared woodruff key can make a not start to/or faulty kill/key way switch.
88-02 4 wire stator 03-06 5 wire stator/and different cdi's
it is possible to interchange the to0,but need to be done correct.

the year is 10th digit on frame...unless somebody swapped ignition parts/cdi ect..
pilot jet in carb needs to be see through.

gear oil holds 650ml of oil which is about 3/4 of a qt but measure it.

also how are you doing lol

 

[deeeebeeeeee]

Unless the guy you bought it from mentioned taking it out chances are if he was roll starting it or lifting the kicker by hand each time, rather than getting a spring for 5-20 bucks depending on new, used, dis.counted, retail, then he never even bothered to pull the clutch cover and the piece of spring is setting on the bottom of the case somewhere. Its probably lodged under or around a bolt hole with sludge holding it in place, of course regular oil changes will probably free it up so it can unleash I spring steel fury when u least expect it.
Lol, maybe not but similar has happened to me more than once.
Might try to fish it out with a parts magnet , but you would have to figure out if where it was at first, might put an oil plug with a magnetic tip.
It could have already came out with the oil in its own as well, to split the cases or not, it's a crap shoot either way!

 

[Metallica]

If i split the cases, what would I expect? I really don't want to pop it open and have some of the transmission gears fall out on me. And also i talked to the guy who ported that jug, and he said he doesn'tknow what he did exactly. He just went crazy with a dremmel which makes me think another reason why I'm not running is the port timings off. I'm probably just going to get a new top end kit with jug included so i don't have to worry about it. I did also score a reed spacer too

 

[Fast6hand]

If i split the cases, what would I expect? I really don't want to pop it open and have some of the transmission gears fall out on me. And also i talked to the guy who ported that jug, and he said he doesn'tknow what he did exactly. He just went crazy with a dremmel which makes me think another reason why I'm not running is the port timings off. I'm probably just going to get a new top end kit with jug included so i don't have to worry about it. I did also score a reed spacer too

Hey I have a very nice cylinder for sale. It was bored/honed by KOR. It's at 66.50. Still lots of life. Needs one exhaust stud.

 

[deeeebeeeeee]

Splitting the cases isn't too bad as far as requiring any special skills, but you will need a flywheel puller, clutch/flywheel holder, case splitter (similar to a steering wheel puller), torch, 1104 case bond (Permatex moto1),2 a service manual, the knowledge and parts mentioned in KORS, Blaster teardown and assembly vids.
I would go ahead and replace at least the main bearings and seals, and possibly have the crank rebuilt with a new big end bearing.
The good news is while the engine is apart you will have a chance to check/replace all the bearings (counter weight /trans), as well as do the shift star mod which makes for smoother easier shifts, and verify that everything is good in the bottom.
Really you should go ahead and split the cases, if after watching the vids you feel comfortable with it. If you don't, you will probably regret it, about the time you get the top end done and have to worry if the bottom will hold up.


As far as the cylinder porting goes if you can get a measurement to the nearest .1 mm or .010", from the cylinder deck to the top of the exhaust port, and from the deck to the top of the transfers, we should be able to get a pretty good idea of where the port timing is at and if or how it will run. It might be salvageable, but I would get the known good cylinder, 66.5 is only 2 sizes over out of 8 (or 10.

 

[Bluesman]

I will try to find the thread apperently someone seperate the shafts,removed the gear from each shaft that handles 6th, and replaced them with the gears from a banshee. For this or something similar to work: either the gears would have to have the same inner diameter and the shafts be spaced the same between the two quads, then you would have to change both the drive side and driven side gears. Or if the gears had the same inner diameter, and the difference in spacing was equal to say the difference in driven gear diameter, then the driven gear only could be swapped.

No way, no how, not even close to fitting. The Banshee gears and shafts are MUCH bigger. Like about 40% bigger. Also, the shaft spacing on the Blaster is about 1.850". The Banshee is about 2.400".

 

[deeeebeeeeee]

That's crazy, I guess the guy was just doing some wishful thinking, oh well. I was kind of hopeful, since 6thseems like it's only spaced a half gear away and modded blasters can pull a full gear goin into top gear, maybe when I get a chance to run with the new HD clutch and 20x12 tires, versus a 2/3 worn stock clutch, and nearly bald 18x10.50, I wil feel like 6th is more useful.
Sorry for the confusion.