- The Response - I hope I didn't mislead you
into thinking that modifying one particular area (or only
one porting factor) would improve your motors power. I
have always tried to stress that porting has to be
engineered completely - from beginning to end. If you
don't get the results you expected mail me the before and
after cylinder map(s) and I'll try and sort it out. The
one thing the engine shop may have done that (perhaps)
you didn't was cut the ports to a specific time area. I'm
sure they didn't just start cutting without knowing where
his final numbers would end up. Porting is such a
difficult thing to explain - I think I get (some people)
into more trouble every time I open my mouth.
-
- Rick
-
-
-
- You'll have to trust us on this
one. Our so-called "porting" should be all plus and no
minus. We live in a--no metric--no tools-- no help
zone--parts availability is a touch and go thing--we
struggle alone in our shop, but we DO it, just like you
started out.
-
- Our cylinder is (we measured)
nicely round, 1 mm. (.040") oversize, we did not have the
overbore done, we discovered it. But whoever did the
machine work, well, you'd be proud of him. Like they say,
"He done good!" We cannot locate a cylinder hone locally
(of the ball-end brush type) as they are all of a 70 mm.
bore size, will a 70 work in a 67 bore??
-
- Our piston ring "pin problem"
turned out to be just fine, the little Wiseco Pro-Lite is
fine, everything except for the small rod end bearing
play, is fine. We have no help with that. The Clymer
manual lists no recommended "wear limit" so we are going
to mic the little end hole size, the outside diameter of
a new wrist pin bearing, and the pin itself, and see what
we come up with. We will record those measurements for
future use.
-
- You have not created a porting
monster but rather a thoughtful apprentice.
-
- Flyin' Ryan (soon to be
shredding again)
-
-
-
-
- The first cylinder I ported actually turned out
pretty good. It started with a Dremel but ended with a
whole bunch of Foredom stuff. I just couldn't leave the
transfer ports untouched - they were way under the
recommended time area for the target speed I was shooting
for. Little did I know that I had the been bitten by the
2 stroke porting bug - and it wouldn't be leaving me any
time soon.
-
- The ball hone is something I have no experience with
- I understand you need to get one "sized" smaller than
your bore size to fit and work properly. I am lucky
enough to have access to a nice little Sunnen hone which
does a wonderful job - and I'll be using it real soon
since I'm almost done with my GP760. It will be time to
give it a hone, change the pistons and close up the
motor.
-
- I just got involved in a little Blaster project of my
own. My son twisted Jason's Blaster up a little too tight
and spun the lower rod bearing. I was so proud of him -
his first rod bearing and he's only 10...<jk> Since
Jason was not able to ride his own quad for the last
couple of days at Glamis I suppose I'll have to
compensate for that by grinding some performance into his
barrel. On the other hand I did let him ride my TRX which
should be payment enough...
-
- It's been a while since I've done any grinding on an
air cooled motor - hmmm... maybe I should make it a water
cooled head... There's no end to what's possible with
that engine.
-
- Rick
-
-
-
-
-
- We would have posted sooner but
we were out at your Web-site having' a look. Great
pictures of your Easter trip. We're glad that you share
the same ideas that many people have here. That being
that the Blaster motor represents many options for
improvement. The water-cooling part has already been
handled by the Yamaha engineers as they made an
H2O-pumper two-wheeled dirt bike, from which the Blaster
motor evolved. (you already know this)--Anyway, if you
decide to do water for Jason, you can do it with stock
Yamaha parts.
-
- Flyin' Ryan
-
-
-
-
- About that piston pin problem - I don't have the shop
manual for that model yet but, the small end is listed as
having a 21 mm hole. For a small end the tolerance
(range) would generally be 20.998 to about 20.008
(metric) - that would put the wear limit (replace it) at
about 21.02. The small ends are usually kept pretty
tight. A 16 mm piston pin will have a tolerance (range)
of about 15.995 to 16.00 and a service limit (replace it)
at 15.98.
-
- The T.E. (top end) bearing is listed as measuring 16
x 21 x 23 (mm). That makes the inside diameter 16 mm, the
outside diameter 21 mm (when the pin is in place, but
allowing for some very small clearance) and the bearing
width 23 mm.
-
- Generally the bearing is not measured while it is on
the pin to try to determine its fitness for service. One
reason this is true is because the rollers may not line
up exactly opposite each other therefore making
measurement impossible. Did you know that T.E. bearings
from different manufacturers may have a different number
of rollers on them? Also sometimes there is a choice of
the amount of rollers available on a bearing - this is
more typical of B.E. (big end) rod bearings, but still is
common to T.E. bearings - you may never know this if you
don't ask the parts guy or ask to see his Pro-X or Wiseco
catalog. It is better to measure the small hole to
determine fitness - because it is the only part that is
not easy to replace. Always replace the T.E. bearing and
pin when the piston is getting replaced. For the few
bucks it costs to replace them it is worth it.
-
- With the amount of RPM's and hard use these quads get
- feed them good quality parts before they ask for them.
They're not like kids that will remind you to feed them
when they get hungry - the starved quad will just start
spewing parts.
-
- Rick
-
-
-
-
- The info about stock 200 cc
Yamaha Water-cooled 2-stroke motors is here. Blaster
Central has a link to it posted on the entry page. Have a
look. It is indeed within possibility to watercool one
with stock parts. The available large Blaster motors we
are aware of are the 240 cc and (I think) 265 cc. The
240's we see in the Dunes. The 265 is a drag race only
motor, as it runs VERY hot, the one that we saw actually
burnt the paint off the motor and did not live long. But
it was impressive while it ran :)
-
- Flyin' Ryan
-
-
-
-
- I know a little bit about the Blaster engine - but
not enough about its roots. It has a tremendous amount of
bosses, fittings and rubber covers which indicate service
in several different models. I don't know which model to
order from to make it water cooled - do you have this
info?
-
- Tonight in my garage I was noticing how easy it would
be to bolt on a Banshee top end. I have a set of Banshee
barrels I'm working on right now that have the 66 mm bore
size (that's +2 mm for a Banshee but standard for a
Blaster). It seems that some careful cylinder work could
easy match (space out) its bolt pattern to that of the
Blaster. Overall though it might be a very pricey
- project - but it would be fun to see how it would
run. I would guess it would be a 30 HP engine without too
much difficulty - at the same displacement as the
Blaster.
-
- Since the Blaster and the Banshee share so many
components (rods - different part number - same
- dimensions, T.E. and B.E. bearings, and their pins),
it opens a few avenues for interesting changes. How about
a long rod Blaster (+5 mm), or maybe use the Banshee 409
big bore kit pistons to increase displacement quite a bit
without resleeving - or sleeving and use the 420 kit
pistons (you'd have to use a base plate spacer in either
case). By not going out to the heavy 72 mm piston
you'll
- rev quicker, vibrate less and the bores will last
longer.
-
- The Blasters' oversize pistons go to 68 mm from
Wiseco & Pro-X. The big bore (409 cc) Banshee pistons
start at 68 mm and go to 69 mm in 4 additional steps.
This would make a Blaster displacement of 213 cc - up
from 195. That's just about 10% more displacement in your
pocket. As far as I can tell there is enough material to
allow for it too. The top of the liner in the Blaster
barrel measures 71 mm. Since these are cast in place
liners they can be bored very thin and still work fine -
they have a lot of aluminum around them for additional
support. The Banshee can safely be bored to 66.50 mm. The
top of the liner measures 68.50 mm which leaves the same
amount of material if taken out to that size. Given that
the Banshee is a more severe service quad - I think it is
safe to say that if the Banshee can survive at those
dimensions, so too can the Blaster.
-
- Sleeving the Blaster barrel for the 72 mm (240 c) big
bore kit would allow for boring in the Banshee 70 mm
piston (and base plate spacer) for a displacement of
219.4, or better still, stay at the larger 70.50 mm piece
(222.5 cc) and run it that way until it's ready for a
bore. In any of these cases it may be an advantage to use
the base plate spacer to increase crankcase volume since
the displacement has been increased. I certainly would
stop at 70, 70.25 or 70.5 mm on my way to the 72 mm
pistons (232 cc) because there are only 2 replacement
oversizes (72.5 and 73) and the barrel must get sleeved
again.
-
- Rick
-
-
-
-
- Well. Here's my two bits.
-
- On Blaster big bores: Kit are
available up to 300 cc. But I think that's more of a drag
kit and it's not likely to last long.
-
- Water cooling: This is just a
bunch of shop stores, none I can prove or have seen. I
have been trying to track back the Blaster's engine for
some time, but I don't have a lot that's firm. I think it
dates back to '74 as a DT200. Between then and now it
gets fussy. Apparently it has been used in quite a few
different dirtbikes. With some air cooled and others
water cooled. I get numbers like DT200 and WR200 and a
WR200(something). As far as I can tell, the case stayed
the same for most that time. Evident buy the Blaster's
castings for a water pump and possibly a old pump. Just
the cylinders changed.
-
- The stories go that you can
take a WR200 (or something like that) cylinder, pump,
etc., and directly bolt it on to the Blaster's case.
Bingo. Water cooled. But the lack of any kits on the
market leaves me wondering.:)
-
- I keep my eyes open when I go
to the dealer for a WR200, but have not found one yet. I
have seen (not close up) a few dirtbikes with the air
cooled version of the Blaster engine. But I don't know of
it was a DT200 or WR200.
-
- Now I have a question. Why do
you want to go water cooled? I have personally driven my
Blaster in heat so hot that I have to keep it below 20
mph or the hot air peals my flesh off. (something around
110) Other water cooled dirtbikes I have been width have
overheated and I had to pull them home. So why add the
complexity?
-
- YFS200 - Nonexistent parts
don't break.
-
-
-
-
-
- Larger displacement is always cool - however I'm not
a fan of vibration. For me the additional vibration from
the heavier piston keeps me away from going to the
largest overbore sizes available when I'm making an
engines displacement larger. For example my 270 cc TRX -
it is much better than the Pro-X (310 cc on up) tops
which vibrate my hands numb after a few minutes.
Three-hundred-feet-at-a-time racers could live with
almost any amount of vibration, but I take rides for
hours - and when I get back I have to have enough energy
left to start the blender to make margaritas.
-
- I took a look around the web and noticed the WR200 as
being an Australian specific model, and the DT200 a
(more) Canadian specific model. Apparently both of these
models are being sold as current models - or at least as
current as 1998 in Australia - perhaps Yamaha dumps
N.O.S. there. There is also an WR200R.
-
- It seems that there were changes to the DT200 (1990
to 1993) to allow its use as a road going street bike -
or at least a version of it was produced that way. This
would explain the oil injection (street bikers don't like
to carry around oil) and maybe the reason they chose the
lower end for use in the Blaster - it already had the oil
pump. Entry level 2 strokes would normally be designed as
simple for its owner to operate as possible - oil tank,
gas tank.
-
- Because these models were not intended for use in the
USA - dealers will not have the micro fiche. They can
order it though. Parts will usually have to be bought
through a dealer outside the US. I had to do this when I
rebuilt a RZ500 a couple of years ago. It took no longer
to get the parts than it would from my local dealer.
There are dealers in places who specialize in these kinds
of sales and are enthusiastic about helping out.
-
- I agree that the Blaster operates fine with its air
cooling - but lets not pretend that liquid cooling in not
a tremendous advantage. Like you said "I have personally
driven my Blaster in heat so hot that I have to keep it
below 20 mph or the hot air peals my flesh off." Case and
point - enter liquid cooling.
-
- I looked at your page with the billet head and
radiator - what a rip off - price wise. It's not truly a
water pumper since it uses thermo syphon technology. I
did the same thing to my Odyssey's almost 20 years ago.
It works pretty well and is better than not having it,
but I wouldn't be surprised if you could buy all the REAL
Yamaha parts at a salvage yard outside the US to convert
it to a REAL water pumper for a couple hundred bucks less
than what they're asking for that kit. To make a system
like that set up I would start with a correctly sized
dome from Pro-Design (to save time). Then make a shell
for it using a mill and lathe. I'd screw in a couple of
brass fittings to attach the water lines and use a heater
core from a popular automobile to get rid of the heat -
even a radiator from a motorcycle salvage yard would not
add that much additional cost. Total cost to make - about
$80 - $90. Total time to make - about 2 hours. I would do
this head project for the fun in it - if I decide to do
it at all and then only if I were going to increase its
displacement by any significant amount. With thermo
syphon there are no (moving) parts to break. When a
watercooled engine overheats there are usually 3 things
that caused it.
-
- 1) Ignorance
- 2) Ignorance
- 3) Ignorance
-
- There is no reason for this to happen at all.
Properly jetted, properly maintained machines don't break
down nearly as frequently as those who never receive any
attention. As I'm writing this I'm thinking about the
poorly designed cooling system (ultra cavitation) of the
LT500 and the poorly designed water pump shaft (snap!) of
the Banshee. It still comes back to ignorance - though
the blame falls on the manufacturer not the owner. It's
funny to me that Suzuki became aware of the cooling
problems with the debut model 500 and chose to give the
barrel/head an additional head bolt to keep it's fluids
inside. This is a prime example of curing the symptom not
solving the problem.
-
- Rick
-
-
-
-
- Ah, the plot thickens. One of
the unfortunate byproducts of making more power is making
(much) more heat.
-
- Anyone that runs a high
horsepower 2-stroke should have an exhaust gas
temperature gauge. Having said that, what options are
there to be rid of the excess heat? Jet it richer and
watch the EGT? Yes, but there must be a point at which
adding more cooling fuel, ends.
-
- Enter watercooling. If the
horsepower of a 2-stroke Blaster could be doubled, ie
34.4 horsepower, it stands to reason that there would be
double the amount of cooling fin area needed to keep the
motor air-cooled.
-
- The only option left is to pump
water through it. A giant heat sink of water. Water
allows for a more reasonable amount of thermal expansion,
and simply put, the metal lasts longer. The cylinder
stays round(er), the rings seal better, and the motor
itself produces back to back nearly identical power runs,
regardless of ambient temperature.
-
- We like the idea of using the
frame tubing itself for a radiator, much like the old
English bikes did for motor oil. (BSA's?) If orifice
plates were used in the tubing, the water flow could be
slowed enough to make it work. By the time the coolant
came back around, the temperature differential would be
just about right, so no thermostat would be needed. The
200 cc stock water pump would need to have it's impeller
turned down. The only things you could see (that would
jump out at you) would be a hose in from the
- frame to the inlet side of the
pump (which is all hidden) and another hose out to the
other side of the frame. Clean and simple and
trick.
-
- Flyin' Ryan
-
-
-
-
- Quote:
-
- I agree that the Blaster
operates fine with its air cooling - but lets not pretend
that liquid cooling in not a tremendous advantage. Like
you said "I have personally driven my Blaster in heat so
hot that I have to keep it below 20 mph or the hot
air
- peals my flesh off." Case and
point - enter liquid cooling.
-
- I think I should restate
that.
-
- "I have personally driven my
Blaster in heat so hot that I have to keep it below 20
mph or the outside (not from the engine) hot air peals my
flesh off." Try 114 outside temp.
-
- I think I understand the what
you are saying. Shoot, I would sure like to convert it to
water cooled just to see if it can be done. But here's my
point. On a stock bore (not a big bore) Blaster, I can't
see the advantage of water cooled when the stock air
cooling does so well.
-
- Now with a big
bore.....
-
- I guess I am just tired of
people coming up, examine my Blaster, and do the "shame
it's not water cooled" thing. When I ask if they ever had
or heard of a Blaster overheating, they can't think of
any thing. Then I tow them home. :)
-
- I agree on the billet head.
High price for little help. The interchangeable domes are
trick, but the manufacturer says he is working on a
interchangeable dome system for the stock
head.
-
- You found a lot of info quick.
That little engine sure gets around. Speaking of, in 4WA
they call it a 80's IT200. More numbers!
-
- [quote]
- There is no reason for this to
happen at all. Properly jetted, properly maintained
machines don't break down nearly as frequently as those
who never receive any attention.
- [/quite]
-
- Then there's our vintage '86
Honda 350 4x4. Never seen a gentle day in it's life, and
little maintenance. A few weeks ago, I was moving rocks
with it. I think I had about 2,000 pounds on the
"HomeDepot special" flat bed trailer. Had about 500
pounds on the rear rack for traction. It just sort of sat
down and pulled that load up the hill. Darn thing won't
die.
-
- I have been thinking about
racing it in the next Lake Elsinore. :)
-
- YFS200
-
-
-
-
- Funny as it should seem - it is possible that the
exhaust gas temp (EGT) is fine and the engine temp is
still too hot. Jetted correctly some motors still run too
hot at some RPM's. It may help to monitor the cylinder
head temp (CHT) as well.
-
- I don't think it's hard to double the output of the
Blaster to 34 HP. The problem is its ability to get rid
of the additional heat. It could drink some nice high
octane fuel to keep it in check though. I would retard
the initial timing a couple of degrees too. Perhaps a bit
lower (sustained power) around 30 HP would be more easily
attainable. That would give it the roughly the power of a
stock 250R with the lighter weight and the smaller size.
It might be a handful.
-
- Adding material to the head and barrel - either clip
on or weld on - to increase the surface area would be of
benefit. Remember the Maico or CZ (Jawa) 250's of the
70's and 80's? Those heads were huge, and for a good
reason. Those 250 cc 2 strokes pumped out serious piston
port power for their day. The massive head would keep it
all together.
-
- Frames used as radiators pose separate problems. When
a frame is welded together it creates a bunch of internal
debris. This debris must be purged from the system -
filtered out - before it can be used. It also gets very
hot and is not a very efficient way to dissipate BTU's -
its surface area is too small and its metal holds its
heat far too long - mild steel cools off slowly. A small
radiator, about the
- surface area of a walkman would be enough to remove
the heat from a thermosyphon system - especially if it
had a rectifier driven electric fan blowing on it all the
time - I know added complexity, but sometimes additional
parts are necessary for their intended purposes.
-
- YFS - Water cooling can be done - its just a matter
of locating the right parts. I'm sure they are out there,
that engine had them at one time. You are right though,
there is no reason to do it other than it just being a
styling exercise. I could mill out a billet water cooled
barrel and sleeve it to YFS specs in a matter of hours.
That's not the point either, the point is locating the
factory stuff.
-
- When I used to race Odysseys, those air cooled 250 cc
2 strokes with the very minimal amount of cooling air
they received survived well too. And with their
dimensions, they could be made to put out serious piston
port power - somewhere in the range of 40 HP - sustained,
and the big boys with their YZ watercooled tops, put out
about 50.
-
- Perhaps the best thing about the Blaster is that it
is so easy to work on. I forget how easy it is to check
the internals of the air cooled world. It is fast. Water
complicates things - far too much for the Blaster user.
The Blaster is by all definitions of the word(s) - easy,
simple and fun to work on.
-
- IT200 - Hmmm I don't remember that bike as being
liquid cooled. Maybe I'm mistaken.
-
- Maintenance is a funny thing - I knew a guy that was
35 years old and had never brushed his teeth for as long
as he could remember - they were green in all the right
places - ugh... When he went to a dentist - because
people pressured him to get them cleaned - he had no
cavities. Everything was perfect. I don't know what to
say about that.
-
- Rick
|
