- The Response - As a
general rule of thumb, with the probe placed 4" from the
PISTON face/skirt readings should be in the range of
1000-1150 for WOT.
-
- Your rise in temps while
cruising (partial throttle yes??) may be an indication of
leaness in the midrange, go to a shorter needle or try
lowering the clip. This is why I love my EGT, mid range
tuning is a snap. You want your mid range tuned as rich
as you can get it without running into ride-ability
problems. The why--when you roll out of the throttle fuel
is dumped into the cylinder cooling it better than
running it on the leaner side of tune. Find that sweet
spot that allows the coolest temp's for partial throttle
settings, but no ride-ability issues.
-
- My MSD ignition. was havoc to
my EGT, it would bounce from 700 to 1400 within seconds.
I relocated my probe wire and have had better success
with it.
-
- Sounds like you may need to
spend an afternoon tuning, taking notes of changes made
and results of changes. Your temps sound to be in the
ball park, but I think that some more fiddling will be
necessary to get where you want to be. Hope I
helped!!!
-
- Backcountry
-
-
-
-
- The model I bought is for kart
racing, so the instructions say to mount it 1 3/4" from
the face of the exhaust port. Not the best measurement.
But 1 3/4" is as close as I can mount it to the engine.
It's also about the farthest or the frame gets in the
way. Most likely it's real close to 4" from the piston.
-
- With a 310 main, I had killer
mid range, but no top. I will try a needle change. Most
of my riding is mid throttle, with short burst to WOT.
-
- I have a few ideas I can try -
I did my best to run it away from the other wires. To be
exact, on the other side of the gas tank. O-well, if I
don't get it, Digatron makes optically isolated sensor
that connects direct to the coil. That will fix it.
-
- I just wish it was only one
afternoon! I have been messing with the jetting for 4
days now. Each time I mess with it, something else goes
wrong. Like this missing after I let off the throttle
from going WOT. Before that, loose coil. Before that,
spark plug not gapped exact. Before that..... You get the
point. Thanks for the help.
-
- YFS200
I noticed that you've blocked off the oil injection - so
I guess you must be mixing gas now. That means larger jets -
the oil displaces space that used to be metering only gas.
Your ratio will dictate how much to increase them. Just
guessing with an 50:1 ratio you would need an additional 3
to 4 jet sizes on account of that alone, maybe more.
With the probe at 4" from the piston face I would say
that you would see temps in the range of 700-800 (degrees)
at 1/4 throttle, 800-900 (degrees) at 1/2 throttle, 900-1000
(degrees) at 3/4 throttle and 1000-1100 (degrees) at WOT.
Engines can melt down in the midrange - so pay attention to
the temps there too.
The CHT you state seems very high (500+) . Why not try
and jet this motor from the low speed on up. Hold a part
throttle setting and note the EGT/CHT readings - adjust the
needle to the desired temp. Hold it a little further open
and do the same. When you get over half throttle start
thinking main jet, but it may change the other part speed
reading as well.
About detonation - When jetting, if you change to a
smaller jet (or leaner clip position) and your EGT goes down
(or stays the same) and the head temp goes up - expect
detonation. An example - If you are dialed in and running
fine at 1200 (degrees) EGT and 400 (degrees) CHT use this as
a baseline. If you change to a smaller jet (to increase EGT)
and the CHT goes up but the EGT goes down, don't jet any
leaner you are (or may be) detonating. You need to reverse
your thinking and jet up. Mounting the probe further away
from the piston will show increased temperature. If it is
placed at about 7" to 8" from the piston face it will read
1200 to 1300 (degrees) at WOT.
I'm not going to ask you the corrected or uncorrected
compression ratio, but what is the static compression you're
getting now?
Rick
- I tried a 290 main jet. The
stalling went away a lot. A little higher exhaust temp,
but the head is now at 522. I am in no way want this
jetted on the edge. I would prefer a jet it and forget
it. But the exhaust temp is way too low and the head it
too high. Before the porting, I was running a 280 (main
jet). I have not touched the needle since before the
port. Mid range is not too hot either. I think the
Digatron gauge is picking up some noise as I have seen
RPM in the 12,000 for a few seconds. Then again, it is a
small engine.
-
- The compression seems to be
holding steady at 135 PSI for the past few rides so I
think the engine is broken in. I mix my oil at 32:1 with
YamaLube. I have been doing that since before the porting
(and running a 280 main). Keep in mind that I am running
the LRD needle and a LRD 30 pilot. I am now running at a
300 main. I don't have a long run to test it on, but
power is great, temp is low. I tried a 310 but that's too
rich.
-
- I moved the clip down one for a
little richer. A lot better in the mid range. A LOT
better. I did a few drag racing test on a short strip. I
can now launch in second and it will pull the front end
up a little in 4th. With that 2+ swing arm, it's really
controllable and easy to ride. Same with my new power
band. But I am having a really nasty problem.
-
- The idle temp is high at 360
(degrees). That's with the air screw all the way in and
the idle set as high as it can go. Should I mess with the
pilot jet? But that's not the nasty
problem...
-
- It runs fine if I keep the
RPM's high. Let's say I spin a bunch of 3 gear WOT
doughnuts. If I keep the RPM's somewhat high,
everything's fine. But if I let the RPM's drop, to around
3,000, it starts to miss really bad. Just like I was
switching the kill switch on and off. It will just barely
run, sometimes stall, and sometime backfire. I can not
drive it at all or get the RPM's up (bogs). It will do
this for about 2 minutes, then, all buy it self, start
running perfect again. I can putt around fine. All goes
well. But if I work it hard, and drop back to idle, it
will do the same thing again?
-
Richening the air screw makes this
worse. (so did going from the 290 to 300 main) This has got
me totally confused. Where do I even look? Yes, the float
level is correct, but that's not what really happened when
the float got stuck before.
YFS200
- The 135 PSI seems a little on the low side - OK for a
stock Banshee but a single (even air cooled) should read
higher than that. I would expect it to be around 160 or
better - even for use with 92 octane pump gas. I'm not
sure that it is broken in yet. Has there been more than a
tankful of premix run through it since you put it back
together? Even if it were not completely broken in - I've
never seem compression increase 25 lb. from a run in.
Perhaps it was designed that way. Do you know what the
compression was
- before you had the engine work done? Did you perform
a leak down test? Was the test performed with a reliable
gauge? What
- is the altitude where you are testing?
-
- I'm glad you decided to stick with the same gas/oil
ratio to run this new top in - it will work out fine. The
Yamalube is supposed to be good stuff. I noticed the LRD
jetting setup on your web page one day - it seems like
they really took some time to sort the Blaster jetting
out. I have heard others say it is a good investment. I
would guess LRD puts the kit together but does not
manufacturer the needle or pilot jet - so I'll assume the
parts are standard Mikuni pieces with different
specifications (sizes). I have no idea which direction
the LRD pilot jet took you - was it a smaller size jet
number (leaner)?
-
- It's not uncommon to have to change the pilot jet
(and everything else) after porting/head modifications.
The suction/pulse timing, strength and duration will be
different at idle (and everywhere else). It may even idle
a little choppy - kind of like a cam in a 4 stroke. My
bike sounds like a pop corn popper at idle -
"tank-ta-tank-tank-tank-ta-ta-tank-ta-tank-tank." You
didn't say whether it's the EGT or the CHT that's reading
360 at idle - that would be on the high side of a normal
temperature for the EGT, though for a CHT it would be
high indeed. If you're turned all the way in (full rich
if its like most carbs) and you're idle adjustment is up
all the way (fast) and it won't hold an idle, then yes a
larger pilot is indicated. Start one size larger - you'll
want to settle on a size that allows adjustment like you
used to have - buy 2 sizes larger just in case. It would
be rare to have to go farther than that. Double check for
air leaks - it kind of sounds like one. Reed cages and
base gasket are the most common place for them to occur.
If you can't leak down test - get some WD40 and spray
suspected gaskets while the engine is idling. Usually
with a 2 stroke if it sucks in
- WD the motor will lose RPM. Berryman's (Chemtool)
however may make the RPM rise - it can remove paint as
well and stinks.
-
- The main jet is usually the easiest to set - start
big and let it blubber - then work your way down.
Especially now that you have a EGT/CHT gauge it will be a
piece of cake... that is once you dial in your baseline
jetting. Going from a 280 to a 300 is not that much of a
change considering the work that has been done to your
quad - quite an impressive list I might add. I would
guess the oil injection accounts for at least half of the
jet increase - you may have been jetted a little fat
before.
-
- That really nasty problem is interesting. The first
thing that came to mind was a fouled plug - but you say
it will run ok again in a couple of minutes. A fouled
plug almost never does that. Change it out just to
eliminate that as a source but check the whole electrical
system - especially the spark plug boot and wire.
-
- A backfire in the exhaust usually indicates a rich
condition has left unburned fuel in the pipe and the hot
exhaust passing through it will try and fire it up -
especially right after letting off from WOT. A backfire
through the carb would indicate more of an ignition
timing problem - check to see that the ignition timing
mark is lined up right.
-
- It's interesting that you noted richening the idle
mixture screw made the problem worse - we are talking
about turning the screw in (clockwise right?) - I'm still
assuming it's an air screw not a fuel screw. Having said
that, it is more common for a motor to pop or backfire as
a result of a lean condition at lower RPM than from a
rich condition at the same RPM. Did this problem start or
get worse when you lowered the needle clip to fatten up
the midrange? I'm assuming you plugged the hole in the
carburetor (or where ever it is located) which used to
supply the oil injection - that could cause a terrible
air leak and you would have problems at low RPM - it's
just about the right size. Also check the carb top - it
could cause an air leak too.
-
- Another thing that came to mind was the low-ish
compression - sort of working against you at low RPM and
perhaps is loading up - but that even seems kind of far
to stretch. I just want to be sure that you're not
mistaking the sound of a ported engine for a poor running
machine. Porting and pipes do make engines behave
differently at low RPM. Other than taking the carb apart
and checking for dirt (or something being loose) and
putting it back together I can't think of anything
else.
-
- Someone once told me that the source of 90% of
electrical problems are carburetion. I have found that to
be true on quite a few occasions. Double check
everything, then sleep on it and double check everything
again in the morning. Let me know what you find out.
-
- Rick
-
-
-
-
- I figured that it (the
compression) should be higher too. I told Duncan that I
still wanted to run pump gas, he said that race gas was
better. But I didn't want to miss a day of riding if I
ran out of the stuff. I told him to make it so I can run
pump if I had too, and I will try to run AV gas or VP
when I can. But before I try that I would like to at
least get it running correctly. I have ran about 4
gallons in it so far. And I did the warm up, cool down
cycles like Duncan said for break in.
-
- It was on the original '89 bore
before I did this. So compression was a little low at 120
psi. Our other two stockers run at 125 psi. That seems
normal.
-
- I made my own (leak down)
tester with an air 0-60 gauge (all I could find). After I
got the leak out of my tester, It held 7 psi for over 10
minutes and the gauge had yet to go down any.
-
- I'm doing my testing at 1,400.
feet.
-
- I like the Yamalube. When I
removed to top end of my Blaster, the piston only had a
small layer of soot on the top. And that's after 6 years.
-
- The LRD jets are a nice little
kit. The needle is longer and has six clip positions over
the stock 5. You run a smaller pilot jet. A 30 compared
to the stock 32.5 (I think, I lost the stock little
thing). Then you run a much larger main jet. It works
well.
-
- My Blaster sounded like that
(tank-tank-ta-tank-tank) before porting with the FMF
pipe.
-
- It's the EGT that's reading 360
degrees at idle.
-
- I hope my dealer stock the
smaller jets. I will try it.
-
- I really don't think it's an
air leak, the pressure test was good and I have not
removed the reed cage since I first did the pressure
test. It was on the rich side before. A 310 main is way
too large and it just blubbers on the top end. A 300 may
still be a little rich, but I am happy with the
performance.
-
- Me and the electrical system
have never gotten along. A few years back it did a back
firing and poor running thing. Turned out to be water in
the switch. Some time later. It did it again. I was using
a BR8ES Odyssey plug, switched to the proper B8ES plug
and everything's fine.
-
- After the porting I put a new
plug in - really poor running and missing. I moved the
plug gap from .30 to .28 - fixed it. A little later, I
had and intermittent poor running and missing. Forgot to
tighten down the coil. Scraped the powder coating off for
a good connection and screwed it down hard - fixed that.
Each time I fixed it and it ran fine. Then when I mess
with something, it does it again. Now I am having this
problem. I have a gut feeling that it's electrical. Today
I am going to try and switch coils and see what happens.
-
- You're correct about the air
screw. Yamaha calls it a Pilot air screw. When I turn it
in, temps go down and RPM's drop. A good setting for
performance is 4 turns out.
-
- When I richened up the midrange
(needle clip setting) it made the nasty, poor running
problem worse. When I had a 290 it was a lot
better.
-
- The oil injection screw on the
carburetor is plugged. I have some K&N air filter
grease I use on the carb top.
-
- About the porting/head mods -
when it does run, it runs great. Good low end. What ever
Duncan did to this engine, I have good power everywhere.
That should improve when I junk the FMF and get Duncan's
PTR pipe that the engine has been ported to. But for now,
the FMF is great.
-
- I have about 1/2 can of B-12
left. I will try cleaning the carburetor. I have all of
Sunday afternoon to play with it. I will take notes and
let you know.
-
- Would it help if I made a MPEG
movie of it missing? Thanks for the help.
-
- YFS200
-
-
-
-
-
- I'm impressed with how thorough you tested/checked
things.
-
- I'm still not crazy about the final compression, but
it may be that with the tuned affect of the pipe it works
better with lower compression. It IS above the number put
out by your other stock machines. Fourteen hundred feet
of elevation will take some "fill" out of the air, but
not very much - perhaps 7 - 10 lb.
-
- Didn't I see a Blaster pipe test recently in one of
the magazines? The Trinity pipe pulled the highest power
from the stock Blaster (read STOCK Blaster). All the
pipes tested were within about 1 HP of each other at the
peak (or something very close like that). The difference
was marginal before and after the peak. I don't know if
I'd scrap the pipe in favor of a PTR piece - it may not
make that much of a difference.
-
- Four gallons (to me) means it has had plenty of time
to "run" in. I usually do it in a tankful, more with a
tight (.002") bore. I'm glad you made a leak down tester
to use on your new engine - they do save
time/money/effort in the long run. It sounds like you
have control of the leak down situation.
-
- The EGT is a little high, but not that unusual. Mine
runs around 325 (if I remember right) after riding it for
a while, then slowing to an idle. If I just start it up
it would take some time for it to reach 325 - perhaps
several minutes if cold.
-
- Four turns out on a pilot screw seems like a lot -
perhaps beyond its useful range. Was it always that far
out? Usually adjustments will be made between the 3/4 to
2 1/2 turn range - if not a different jet is usually
needed. It interests me that the condition was worse with
a richer needle position because that would seem to
indicate a problem with the firing of the mixture.
Usually a pipe won't make a motor miss (if its going to
at all) until its power peak so I'm thinking spark again.
Also you shouldn't be noticing the effect of the main jet
at that RPM (we were talking 3000 I thought), its funny
that changing the main seems to make a difference with
this "nasty" problem. It's a low RPM miss that acts like
a high RPM one. A broken reed can act like that too - but
not make itself better in a few minutes.
-
- Since you've had little electrical gremlins sneak in
on you from time to time it may be that something is not
getting a good ground or something that loosened. I hate
tracking down problems like that but it sure is nice when
the answer presents itself. I've had the plug gap thing
too, and the coil wire that was arcing to the frame from
a break in its outer skin - among others.
-
- If you don't get any positive results from further
tuning today, go ahead and make a mpeg. I don't know if I
can tell anything else by listening to it because we've
covered most of the bases. I have a good idea of the way
and condition its running from your description. Let's
see if you find anything while working on it today. Let
me know what happens.
-
- Rick
-
-
-
-
-
- Today, I was spinning doughnuts
WOT and leaned over and placed my head real close to the
engine. Sounds a lot like it's knocking to me. Maybe
there are weird things going on that raise the
compression when it's running. I will see if I can pick
up 5 gallons of AV gas today and see what happens. I have
ran AV gas before and it always reduced the knocking.
-
- The Trinity is the highest
power pipe. But not much of a power band for trail
riding. It's also too loud. I was just thinking that the
PTR porting is matched to the PTR pipe. As you know,
swiping brands around can lead to flat spots. But that's
later. I want Works (shocks) first.
-
- All the gaskets still look
good. A used a thin layer of high temp grease on the
gasket surfaces. I think that's why it sealed so well. I
would do another leak down test, but to get the pipe off
I have to remove the EGT probe, fenders, and other stuff
I don't want to mess with right now.
-
- The slow jet setting was not 4
turns out until after the porting was done.
-
- I have some more information.
When it goes into it's "nasty" problem, I let it try to
idle and the EGT holds steady at about 457. Higher then
it normally idles at 360. Now when it's throwing it's
fits, I can't get the RPM's up or move at all. If I pull
out the choke, it sputters like the choke is on, but I
can get the RPM's back up, turn off the choke, and
continue on my way. That does not sound like an
electrical problem to me. But who knows. :)
I ran out of new plugs so I used
a slightly use one. I also cleaned out the carb best I
could with 1/4 can of B-12. I did make sure the pilot jet
was clear. It did run better, but it always runs better
after I clean out the carb. (Or did I just think it ran
better.?) The old plug I removed is mostly black with a
nice brown on one side. Don't know why that
is.
Monday I will see if my dealer
(MMS) has pilot jets in stock and pick up a few sizes
larger. I will also pick up a few plugs and air filters.
Then it's on to Hank's for metric nuts & bolts for
the skid plate. And hex head M6 stainless bolts for the
engine. (to replace the all-to-easy-to-strip screws).
Thanks for the help.
YFS200
-
-
-
- (Let me find it) - At one time we were talking about
the air screw being turned in all the way and later we
were talking about it being at 4 turns out. Just to
clarify this - if it's running better all the way in, buy
larger (richer) jets. If 4 turns out is best, buy smaller
(leaner) jets (I'm thinking it is needing a leaner slow
jet - though this plays tricks with the mind. There is
little danger of serious problems associated with that
jet - that is to say I doubt you will melt down at 400+
degrees.
-
- With that compression - no matter what pipe it has -
you should be able to "jet out" detonation (knocking).
Don't be afraid to jet fat to get rid of it. Fat is smart
- it's thin that's expensive. Restrictive silencers raise
piston crown temperature and this increases EGT.
-
- Your description of the spark plug sounds rich. Your
description of pulling the choke leads me to believe that
it is running better by virtue of providing a cooler
mixture rather than correcting the mixture - though I
still have to say that this sounds like an air leak in
many ways. It is confusing to say the least. The good
thing is that for a few bucks you can (probably) dial
this thing in just right.
-
- Rick
-
-
-
-
-
- The only one my dealer had in
stock is a 35 slow jet. I have not had a chance to try it
yet. My LoneStar a-arms arrived and I have been spending
most of my time getting the front end back on. I can
always do the jetting when I get there. Thanks for the
help. It's drivable now, but I have skid plates to attach
that I have to have on for the trip.
-
- YFS200
-
-
-
-
-
- As long as you know you can get the jetting to where
you need it you should be ok. I guess you determined that
it is a jetting thing and not an electrical problem.
-
- Rick
-
-
-
-
-
- You are right about the
jetting. It's not the jetting at all. A fouled plug.
-
- A put a new one in and it ran
perfect and idled at 280 EGT perfectly. I road with a
friend (an 11 year old on a stock 250R - and he can
handle it) a little today. On a short drag, my Blaster
could hang with him fine. Even pass a few times. I need
to work on my shift points more.
-
- By the end of the day, the plug
was once again, getting fouled. What can I do to prevent
this? Should I go with a hotter or cooler plug? (stock
B8ES). Thanks again for all the help.
-
- YFS200
-
-
-
-
-
- Were you just testing me... :) ??? Wasn't a fouled
plug the first thing that came to mind when you described
the nasty problem... though I did say that it was unusual
for it to come clean again though. I always try to
eliminate the simple things first and work from there. A
B7ES may help a bit here but you may just be a little too
fat on the midrange (or top) and be fouling out. You know
this will probably come back to that saying about the
percentage of electrical problems being carburation
related.
-
- You know its funny - I was going through this thread
to see what my initial thoughts were about your problem -
I didn't notice that you sent a couple of pictures of
your Digitron set up until I looked at it a couple of
minutes ago - that probe sure is close to the piston
face. Is that where the directions indicated to place it?
It looks about 3 inches too close for "real" readings.
But a baseline is what you want to establish. You should
do a few plug chops to check jetting (and EGT/CHT) so you
can baseline what its supposed to run like when dialed in
(temperature wise).
-
- Rick
-
-
-
-
-
- I'm leaving tomorrow. I moved
the EGT probe back 3 inches. It's reading higher now.
Strange. Anyway, thanks for the help. I will let you know
how it goes.
-
- YFS200
-
-
-
-
-
- I survived the trip to AZ. We
had a lot of great people including a friend on a 350X.
When I pulled in to camp, my Blaster was not really
running. I had to adjust the needle, and drop the e-clip
on the rocky ground. Just what I wanted. 5 minutes into
camp and I am out of the game. Lucky I found it. I
changed to a B7ES plug. It got the fouling down to a
manageable level, but still does it.
That was the first time I have
been able to really open it up and test. Air temp was in
the cool 90's. At midrange, EGT got as high as 1225. I
don't recall what it was, but the head was staying cool.
In the low 400s. On the few mile long stretches, I held
her open a few times and raced the 350X. EGT settled at
1182 but head got as high as 480. I think a higher octane
gas is required. On a long 5 miles of open road, my
sisters stock 95 Blaster was knocking and pinging so bad
that it stalled.(but started in a few min) I think it was
the California gas we picked up. But mine was running the
same junk.
Back to how mine ran. I lost an
bolt holding an upper ball joint on during the first
hour. I guess I forgot to tighten that one down. I used
plastic pull tights I keep in my tool kit to hold it back
on until I made it back to camp. I picked up a too long
metric bolt and a few washers at an local hardware store
and made it fit.
-
- The money I spent on the
porting is worth every penny. The power band is
incredible. A better low to mid. And a awesome top
screamer. I don't think it suffers anywhere. Over rev is
great too. I can go from putt putt, give it some gas and
get really moving without shifting gears. Speaking of
pulling, when taking off, it likes to spin the tires, but
I can fell when it hooks up when I I get this pulling on
my arms :) Gearing is perfect with the 14 tooth front and
20" tires in the rear.
-
- Had the best time ever. Flying
through the dessert at WOT. Lock the brakes, slide around
the turn, then take a large hump in the road like a
table, and clear the top. Sort of like your ride to
Glamis. If I had the Works and if the brakes where
working at 100% it would have been perfect.
-
- I did put a 13" slice in a side
wall on a front tire. The rear disc has some new
scratches. And I bent my belly plate. Best ride
ever.
-
- A very happy YFS200
-
-
-
-
-
- It sounds like you had a great time! Sometimes our
best rides are most clearly defined by the part we crack,
bend or break! There's always a few bugs here and there
that need to be worked out - it seems that we need a few
days of testing at our ride spot before actually riding
"for real" there. Trips like that always make me create a
parts list for the next time I go so I'll be better
prepared. I love those kind of trips.
-
- It sounds like you were riding in hot (thin) air. The
air quality (density) may have required you to jet a
little leaner - but that's related to so many other
factors it's difficult to say. You were running kinda
warm which plays tricks with my jetting thinking. For me,
the 1225 would be a little too hot in the midrange - I
might have richened the needle a bit (more) - but that
depends upon what kind of load the engine was under. You
were certainly "right in there." The 1182 sounds OK for a
peak temp - especially after such a long
- WOT run - a little on the cool side never hurts, but
the 480 CHT seems a little hot. There may be little you
can do to improve that since the engine is air cooled but
a better quality of fuel (brand name 92 octane) might
straighten it out a bit - it never hurts to keep a
- little 104+ (octane boost) around in case of
situations like that either.
-
- Rick
-
-
-
-
-
- Thanks for all the help. I
think some of this jetting confusion is caused by the
fact that I ordered my EGT gauge from a kart dealer. The
EGT sender is SLOW. I have to stay at one throttle
setting for some time before it steadies out. I guess
kart racing does not require a fast reading. I found an
fast sender on the web I plan to buy and try soon. That
should help.
I went for a quick ride
yesterday. It was cooler out side - 70 I think. It fouled
a plug right off the bat. Was running poor too. A little
too lean from what the EGT was telling me.
I made a few runs and kept a
close eye on the EGT. By GPS, I hit a top speed of 64 MPH
@9K RPM. I'm happy. :) That's as fast
- as a stock 400 EX.
-
- What is worrying me is that it
is still fouling plugs. Even running lean and using a
hotter plug. I have a little spark gap tester thing
somewhere, I will test it this weekend. But I suspect
that one of the coils is going out.
-
- Thanks again for all the
help.
-
- YFS200
-
-
-
-
-
- You're welcome. I've enjoyed trying to sort this all
out. This thread may make it into the Thread Spread in a
while - I hope you don't mind.
-
- My EGT never stays constant. It is always changing -
I think it updates the info about every second, so it's
kind of slow too I guess. When properly jetted the EGT
will rise slightly - do to the internal parts staying hot
longer, this would be considered normal. It may be wise
to always jet to the rich side - just a bit - to prevent
failure do to this phenomenon.
-
- I'm starting to wonder if you're oil fouling the
plugs. This would be different than fouling them due to
too rich of a mixture. At this point I suppose you
wouldn't like to change the oil to gas mix ratio, but
perhaps some sort of modification along this line is
necessary. I can't remember the last time I fouled a plug
due to the fuel to air ratio. I have had to chuck them
after making long runs while riding with small kids on
small bikes (oil fouling) though I can usually prevent it
if I clean it out (rev it up) every once in a while.
Sometimes I can not prevent it and other times I have
ridden round trip to the store from my campsite (about 17
miles at 10
- to 20 MPH) and stopped at comp hill on the way back
to find that the plug is still performing perfectly well
or will clean out after a run or two. I don't know what
to say about that. I do favor lean oil mix ratios though
- as well as pure race gas.
-
- If you were running at 32:1 you might want to try
50:1 (as long as the oil supports that ratio) and see how
it goes. I would think your peak max RPM EGT would go
down a bit (with no jet change perhaps 50 degrees) and it
may be just enough to prevent the oil fouling. You may be
able to lean out the main a bit (and perhaps the mid as
well) after this change to further take advantage of
it.
-
- Hotter plugs have a longer heat path and burn off
more slowly under extreme conditions. It may be necessary
for you to plug it in the other direction to take
advantage of a shorter heat path and perhaps a plug that
will burn off more quickly in the kind of engine
operating condition you're subjecting your engine
to.
-
- Sixty four MPH on a Blaster is Rockin'!! That must be
up a good 15 MPH (guessing) from stock and about 1500
RPM's or so too (another guess).
-
- Rick
-
-
-
-
-
-
- Mine updates every second or
slow too. It just that it takes a good mile of WOT before
the reading stops going up. The EGT sender is just too
slow. I will replace it with a faster one
soon.
-
- I am using YamaLube 2-S. I buy
in bulk, (my dealer gives me a good deal that way) and
then use it in everything. I have about 10 gallons
sitting around. Looking at the one sitting next to my
computer, it shows a max of 40:1 on the chart. I am not
sure I want to try 40:1 or 50:1. I want to exaust all
other options first.
-
- I lost my spark tester. On my
next trip to the dealer, I will order a new one. I have a
gut feeling that it's something electrical. Maybe a weak
coil. Don't know. That spark tester will tell me more. I
will try the cooler plug idea.
-
- More testing is needed, but I
think the porting has made the engine way more picky to
air temp then I wanted. Looks like I have to rejet if the
temp drops 30 degrees. I can't wait until someone comes
out with fuel injection. Or I may do it. Does not sound
all that hard. A little computer that hits a fuel
injector depending on EGT temp and RPM. Need a throttle
valve.
-
- But first I need to save the
buck for when FMF comes out with there SP pipes. I need
one bad.
-
- I get that affect when riding
slow to. We use the stock '92 Blaster to get around at
horse shows. That's a lot of lugging the engine in high
gear to keep the noise down. About 30 minutes of that and
it's starts running poor if you try to go faster. A
little revving to blow it out and it runs fine. But it
never fouls a plug.
-
- I clocked the stock '92 at 57.9
MPH peek. A good average is 55MPH. 64MPH is not that
much higher. My Blaster has the power to hit 70 easily if
I wanted to change the gearing more. But I really like
how it's at now. The spread between gears works really
well.
-
- A stock Blaster's pipe peeks at
about 7,100. Mine peeks at about 8,600 RPM. I have seen
it at 10,000 RPM when really winding it out. Small
engines can really scream.
-
- YFS200
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