ZRT 600 JETTING

ZRT 600 JETTING

Post by SpunkyT » Thu, 28 Dec 1995 04:00:00


Please list any jetting changes that work well.

Thanks

 
 
 

ZRT 600 JETTING

Post by Doug Ritt » Fri, 29 Dec 1995 04:00:00

: Please list any jetting changes that work well.

I'm running 290 mains with a single dial-a-jet on each carb.
At the middle dial-a-jet setting, it's perfect at about +20f.
That would translate to 310s without the dial-a-jet.  And I
have the jet needle e-clip on the second notch.

This is with a fresh engine, it may change after it is broken
in.

--
Doug Ritter


 
 
 

ZRT 600 JETTING

Post by Scott Will » Fri, 29 Dec 1995 04:00:00

Quote:


>: Please list any jetting changes that work well.
>I'm running 290 mains with a single dial-a-jet on each carb.
>At the middle dial-a-jet setting, it's perfect at about +20f.
>That would translate to 310s without the dial-a-jet.  And I
>have the jet needle e-clip on the second notch.
>This is with a fresh engine, it may change after it is broken
>in.
>--
>Doug Ritter


        I've gotta get one of those things, yesterday I ran from 8400 feet to
about 9500 feet and started out really cold, (????? on exact degrees)
and ended the day rather warm.  My Zirt didn't want to run at all in
the morning in the cold and very gradually as the ambient air temp.
increased, it started running better.  I'm running 250 mains now and
that is too fat. With the dial-a-jet, probably about what?  210's or
less?

----------------------------------------------------------------

'96 ZRT600 Mountain Cat for me,
'96 ZRT600 Mountain Cat for the wife.
Northern Utah
(Should've bought her a Powder Special)
----------------------------------------------------------------

 
 
 

ZRT 600 JETTING

Post by Doug Ritt » Sat, 30 Dec 1995 04:00:00

:       I've gotta get one of those things, yesterday I ran from 8400 feet to
: about 9500 feet and started out really cold, (????? on exact degrees)
: and ended the day rather warm.  My Zirt didn't want to run at all in
: the morning in the cold and very gradually as the ambient air temp.
: increased, it started running better.  I'm running 250 mains now and
: that is too fat. With the dial-a-jet, probably about what?  210's or
: less?

The instructions say to drop 2 main jet sizes but they also say to get
it jetted properly before you do.  If 230s are optimum without a Dial-
a-Jet, then, yeah, 210s would be right.

Are you running an EGT guage?

--
Doug Ritter

 
 
 

ZRT 600 JETTING

Post by Tom Aver » Sat, 30 Dec 1995 04:00:00


writes:

Quote:

>    I've gotta get one of those things, yesterday I ran from 8400
feet to
>about 9500 feet and started out really cold, (????? on exact degrees)
>and ended the day rather warm.  My Zirt didn't want to run at all in
>the morning in the cold and very gradually as the ambient air temp.
>increased, it started running better.  I'm running 250 mains now and
>that is too fat. With the dial-a-jet, probably about what?  210's or
>less?

Scott,
   Let me get this straight. The sled runs better at higher altitudes,
and warmer temp???  Right -  REJET NOW!!! Before you melt down!!!

As you go warmer, there is less O2, and therefore the mixture is
getting richer!!

As you go higher, there is less O2, and therefore the mixture is
getting richer!!

This means you are too lean when you start out!!!

DANGER WILL ROBINSON, DANGER!!!!

I surprised that you didn't hurt the engine already.

For Mountain riding the D/J is typically setup for the coldest temp,
and lowest altitude combo that you are going to ride. You want the D/J
to be set full rich. Then as temps climb, or you climb, you can stop
and lean the mixture down to compensate, and keep the sled running at
its' peak performance!

I have installed a Dial-a-Jet, and triple EGT's. Based on some bad
recommendations, I had the jetting way off. It was easy to see which
cylinder was how far off.


cold.  Turned out that I had goofed up the needle on two of the carbs,
and had the E-clip above the little metal plate instead of under it.
Guess which two carbs?!  Next run was much better with all cylinders
in the 800-1000 range. It is going to be easy to see exactly what
effect each change is making at every throttle opening condition. A lot
of people run different main jets, but most run the same needle jet,
and clip position. As widely varied as some of the Polaris Main jet
rec.s are, I believe that the needle clip, and needle jet size may also
need to be varied as well. With the triple EGT's it will be very easy
to tell what is going on!!

Ramble Mode Off:

Later,

TA

 
 
 

ZRT 600 JETTING

Post by Tom Aver » Sun, 31 Dec 1995 04:00:00

Got the Skidoo not a mystery Video in the mail today, Sat. 12/29.

By now we all know what is one the video, but I thought I'd point
out a couple things. If you want to be surprised when yours arrives,
Don't read any farther.

Of course it is a MX Z 670, with a single pipe.

Video starts off with Toni Haikonen and some good riding shots.

Then, our own Kevin Beilke of Race and Rally!!!!

Kevin - you need a new hat :)

Then a cast of other snowmobile rags.

I never thought I'd hear the words CrackJack & Snowmobile
used in same sentence!!

Then the closing "MX Z 670 Strike Force"

All in all pretty well done, but too short.

Also, I want to hear the original sound tracks complete
with engines roaring, rather than music!!

TA

 
 
 

ZRT 600 JETTING

Post by Scott Will » Sun, 31 Dec 1995 04:00:00

Quote:


>writes:

>>        I've gotta get one of those things, yesterday I ran from 8400
>feet to
>>about 9500 feet and started out really cold, (????? on exact degrees)
>>and ended the day rather warm.  My Zirt didn't want to run at all in
>>the morning in the cold and very gradually as the ambient air temp.
>>increased, it started running better.  I'm running 250 mains now and
>>that is too fat. With the dial-a-jet, probably about what?  210's or
>>less?

>Scott,
>   Let me get this straight. The sled runs better at higher altitudes,
>and warmer temp???  Right -  REJET NOW!!! Before you melt down!!!
>As you go warmer, there is less O2, and therefore the mixture is
>getting richer!!
>As you go higher, there is less O2, and therefore the mixture is
>getting richer!!
>This means you are too lean when you start out!!!
>DANGER WILL ROBINSON, DANGER!!!!
>I surprised that you didn't hurt the engine already.
>For Mountain riding the D/J is typically setup for the coldest temp,
>and lowest altitude combo that you are going to ride. You want the D/J
>to be set full rich. Then as temps climb, or you climb, you can stop
>and lean the mixture down to compensate, and keep the sled running at
>its' peak performance!
>I have installed a Dial-a-Jet, and triple EGT's. Based on some bad
>recommendations, I had the jetting way off. It was easy to see which
>cylinder was how far off.

>cold.  Turned out that I had goofed up the needle on two of the carbs,
>and had the E-clip above the little metal plate instead of under it.
>Guess which two carbs?!  Next run was much better with all cylinders
>in the 800-1000 range. It is going to be easy to see exactly what
>effect each change is making at every throttle opening condition. A lot
>of people run different main jets, but most run the same needle jet,
>and clip position. As widely varied as some of the Polaris Main jet
>rec.s are, I believe that the needle clip, and needle jet size may also
>need to be varied as well. With the triple EGT's it will be very easy
>to tell what is going on!!
>Ramble Mode Off:
>Later,
>TA

        Turn that Ramble Mode back on, I'm learning and I like it !!!

O.K., so I need EGT's. I've got "EGT's" catalog somewhere in a pile of
sled literature. Is that the best place and brand of EGT's to get?
How much is the cheapest and most compact I can get into a set of
triple guages?
        Scott.

----------------------------------------------------------------

'96 ZRT600 Mountain Cat for me,
'96 ZRT600 Mountain Cat for the wife.
Northern Utah
(Should've bought her a Powder Special)
----------------------------------------------------------------

 
 
 

ZRT 600 JETTING

Post by TAvery44 » Mon, 01 Jan 1996 04:00:00


Quote:
Willis) writes:
>    Turn that Ramble Mode back on, I'm learning and I like it !!!

>O.K., so I need EGT's. I've got "EGT's" catalog somewhere in a pile of
>sled literature. Is that the best place and brand of EGT's to get?
>How much is the cheapest and most compact I can get into a set of
>triple guages?
>    Scott.

EGT is Exhaust Gas Temperature. HPE and others carry the gauges. Westech
is the brand of gauge I have. HPE, etc. also have single gauge and triple
gauge pods for Indys. The triple gauge pod holds three 2" dia. gauges. It
screws to the top of the instrument pod. Still fits under even the short
windshield.  You'll have to check what they have for Kats. With an
electric fuel gauge, speedo, & tach, plus warning lights in the pod, and
triple gauges on top, it is starting to look like an airplane***pit.

Dan C. convinced me that I should get the triple gauges. He has installed
one on his 707, and really would rather have the triple gauge setup I now
have. If you need to go cheap, get one gauge, and three probes (you have
to buy these seperately). Then switch between probes. Gauges should run
about $40-60 each for a single gauge. There is a dual gauge that looks
pretty good. The triple gauge has too small of numbers, and needles to be
able to read it. Realize that when you are trying to tune the high end,
you are talking about full throttle runs for a 1/2 mile or so!!!

I bought the heavy duty SLP gauges. They are warrrantied for 3 years. They
are $30-40 each. You should get a specific temperature, and position
recommendation from someone who knows Cats. The position is how far from
the exhaust flange you go to mount them. typical is 6-8". You will get
some generic info with the gauge. The XCR SP/Ultra motor has a water
cooled exhaust port. So the EGT temps are lower than the XLT. The
difference is ~200'F!!!

TA

 
 
 

ZRT 600 JETTING

Post by Craig Cleasb » Tue, 02 Jan 1996 04:00:00

Quote:
>you are talking about full throttle runs for a 1/2 mile or so!!!

                                               ^^^^^^^^^
The mileage adds up quick at 100 mph, no wonder you guys ride over 1000
miles a year.

Quote:
>I bought the heavy duty SLP gauges. They are warrrantied for 3 years.
They
>are $30-40 each. You should get a specific temperature, and position
>recommendation from someone who knows Cats. The position is how far
from
>the exhaust flange you go to mount them. typical is 6-8". You will get
>some generic info with the gauge. The XCR SP/Ultra motor has a water
>cooled exhaust port. So the EGT temps are lower than the XLT. The
>difference is ~200'F!!!

>TA

Tom What range gauges did you get for your XLT ?
How far out did you mount the probe ?
Did you run these gauges with stock carb set up before you put your
dial a jets in ?

I now have almost three hundred miles on the 96 xlt special and have
concluded that it is way to rich. I think it has 260 s in it now any
recommendations as to rejet ?

TIA

Craig.

 
 
 

ZRT 600 JETTING

Post by TAvery44 » Wed, 03 Jan 1996 04:00:00


Quote:
Cleasby ) writes:
>Tom What range gauges did you get for your XLT ?

I think they are all the same. 400-1600'F

Quote:
>How far out did you mount the probe ?

With a single pipe you can run one right at each exhaust port.
Or you can run one between the y and the ball joint where
the exhaust pipe connects to the exhaust manifold. If
you have triple pipes, you can put them out past the header connection.

Quote:
>Did you run these gauges with stock carb set up before you put your
>dial a jets in ?

No, Actually I made a bunch of mods simultaneously.
Quote:

>I now have almost three hundred miles on the 96 xlt special and have
>concluded that it is way to rich. I think it has 260 s in it now any
>recommendations as to rejet ?

Go down one main jet size at a time. Read your plugs as you go.
If you don't have a dial-a-jet, then you don't want to get to close
to the edge, or you will have to jet up, everytime it gets colder..

There are significant differences between the 95 and 96 XLT Special
motors. I don't know that the EGT temps rec.s are the same. I have 34mm
carbs, and you have 38mm carbs for example.

TA

 
 
 

ZRT 600 JETTING

Post by Scott Will » Sun, 07 Jan 1996 04:00:00

Quote:

>Got the Skidoo not a mystery Video in the mail today, Sat. 12/29.
>By now we all know what is on the video, but I thought I'd point
>out a couple things.
>Of course it is a MX Z 670, with a single pipe.
>Video starts off with Toni Haikonen and some good riding shots.
>Then, our own Kevin Beilke of Race and Rally!!!!
>Kevin - you need a new hat :)

        But Kev did a good job, huh?

Quote:
>Then a cast of other snowmobile rags.
>I never thought I'd hear the words CrackJack & Snowmobile
>used in same sentence!!

        Yea, no kidding . . . silly.

Quote:
>All in all pretty well done, but too short.

        Yea, great video. I got mine today (01/05/96) I also thought it was
too short. What a great sled though. Really nice !!!!!

Scott.


'96 Zirt 6 for me.            Northern Utah.
'96 Zirt 6 for the wife.  (should've bought her a Powder Special)