Zrt 600 - Snowmobile World : Your #1 Snowmobile Forum

TaxiCat · 02-03-2002, 10:38 PM

I'll get straight to the point. I have a 99' zrt 600. I have gutted the air box (shelf and horns) I *also added a new helix (57/38) this season.
The issue I am having *with it is, *that it seems to run ultra lean!!
I have changed the mains from 350's,360's and now 370's. In addition I have also moved the
"E-clip" down to the #4 position. The sled is still running in the uncomfortable "lean" area.
I know that the tripple 6's like 330-350 mains that is why I am so dumbfounded.
Should I just go up to a 380? Or am I looking at a crank seal (sucking air)?
I.E. compresion check done. A-ok!
Perhaps I am just overlooking something. Any suggestions would be relly appreciated.

hpzrt600 · 02-04-2002, 09:40 AM

Better run a P-4up to a P-6 needle jet.

Stock is P-2. You need more midrange fuel.

TaxiCat · 02-04-2002, 10:02 AM

Thanks for the info. hpzrt600. that was the next thing on my list to try. I'll give that a shot and will follow
up with the results.

jayjaysin · 02-04-2002, 10:33 AM

Did the 600's have the recall on them also in 99? *Look at the recall section.

fullthrottlexlt · 02-05-2002, 01:34 PM

I have heard that if you gut out the air box it will affect your jetting. And if you think that you might have a bad crank seal it will show on the cylinder closest to the seal. An easy check of that is to spray some wd-40 onto that seal while the engine is idiling if the rpms go up at all while you spray on the seal then its sucking air.But if you are lean all the way across then i dought its the crank seal. my 99 zrt is runnig 350

sleddinfool · 02-05-2002, 10:23 PM

How do you know it is running lean? Plugs? EGT? I also run a 99 zrt600 with a black magic mono-block head kit, D&D pipes, and clutching, geared, v-force reeds etc.. I have EGT guages and it seems to run a little on the lean side. EGT temps are always at 1250-1300 on the midrange if I run it hard the temps drop. If I let off the throttle temps drop. I have around 1500 miles with this setup and have not met Mr. squeaky yet.My airbox is a D&D with the shelf and cones also removed. I have never even put a set of plugs inn it either, they are always nice and brown with decent piston wash. Kevin
Oh yeah, I am running 360 mains.

TaxiCat · 02-06-2002, 10:12 AM

I know the sled is running lean because of the piston and
plug color.
I have since my original post, started over from scratch.
I sincronized the carbs again,adjusted the air screws as
needed and rejetted.
I did not have to change either the needle jet (tube) or the
jet needle.
I now have 360's in it with the e-clip at the 4th position
from the top.
I was running BR9ES'S and switched to the stock EYA's.
I found they "color out" faster.
So far so good. Now all I need is some real snow to put
some miles on.
Thanks for everyones input.

Illinois_Cat · 02-08-2002, 01:34 PM

Once the airbox is removed then expect a 3 size increase in jets to richen it up. *You may have to change the needle jet to something a little more richer like Q6. *To give you an idea of where I had to start beofre tuning kicked in on a big triple.

1108 T-Cat
41 Pro Series
No Airbox
Kickass Filters

Started with 530 Main
Q8 Needle
#4 position on jet needle.

I have it now dialed in where I can rapidly adjust with a 40 degree change in air temp or 4000 feet in elevation.

Good Luck

I-Cat

ZRT600MtnCat · 02-16-2002, 01:11 AM

Get another airbox, they are not just an air box, their true name is resonance chamber. VERY IMPORTANT.

DAHMENRJ · 03-02-2002, 12:46 PM

ANY FLUTTER OFF IDLE OR 1/8 THROTTLE. CONSIDER ONE SIZE LARGER ON THE PILOT JETS TOO!! *WHERE EXACTLY IS IT LEAN?