[JR ZRT600]

Finally, a good site for discussion that's not product orientated. Boy am I glad I found you guys!  

Ok, first off this is the first "new" sled I've owned so some of this is new to me. But in my defense I've rebuilt alot of car engines and done tuning on jet ski's so I can handle 90% of the dialect / concepts. Here goes: End of last year I bought the '96 ZRT600, it needed the typical drive clutch replacement, left rear engine mount replacement, lower left drive shaft bearing and some TLC. The sled is basically stock with very few variations. I'm having trouble with the far right cylinder fouling plugs, somewhat high oil consumption and a bog that occurs off the line and at cruising speeds below 5500rpm when you pop open the throttle. From my search I've read that the bog is fairly common with these sleds but mine is not what I would call standard in proportion. Here's the sled's specs for what its worth:
Alt. / Outside temp ridden at  -  under 2000' / 0-30°F
Pilot Jet - 30
Main Jet - 360
Needle Position - 3rd notch from top
Pilot Needle - 2.25 Turns out
Drive Clutch - AC # 0746-087 (stock 2001 style)
Cam Bushing - AC # 0646-016
Drive Spring - AC # 0646-147 (yellow/green)
Driven Clutch - Original AC with yellow spring and #47 Helix
Compression - On the low end of spec but within 3# variance
Resonator - Bubba's hack shop stock box, somebody cut the inside wall off and hacked away at the innards then welded a plate back on

Engine, pipes & most likely gears - Stock
Throttle position sensors - still connected (not sure how to bypass)

Questions:
1. Can I allign the clutches, if so how and can a tool be made rather than purchased?
2. Where should the oil pump marks be?
3. How do you bypass the throttle position sensors?
4. I realize that the pilot jets are on the small side should I bring them back to stock (35mm)?
5. I also realize that the mains are slightly large, but I would rather loose a little performance and gasmileage to stay away from lean burn. Should I change them too?
6. Will Bubba's hacked resonator cause a need for rejetting?

Thanks for reading my book  

and trust me any info is greatly appreciated.

 

[arcticman]

If its a off idle or low mid range bog it could be the throttle switches, mostly common in twins off idle but i had a friend with a zrt 600 & off idle & lower mid range blubber, only ran descent at fairly higher rpm, should be a jumper  bypass plug with the sled to test for this problem, if not call your dealer if ya suspect this problem & get a plug..........

 

[ArTeeCat]

The sled probabbly has multple jetting and clutching problems.  There was a recall on the pipes due to leaking and loss of power.  360 mains are huge.  I ran 320 without pipes and now have 350 mains with psi pipes and slp airbox.  Also the sled needs to be clutched.  Call Livingstons's Artic Cat in Hillsborough, NH.  1-603-464-5454  ask for Steve.  Works real close with Hooper Racing and has all the jetting and clutching that will make that sled safe for the trail.  All you need is a few dollars in jets and maybe 100 dollars in clutch parts, then the sled will be brand new fast.    we modified my 96 for the trail and the thing is still flying no bog and fast.  We advanced the timing, v-force, slp airbox, clutched, jetted, and psi modblaster pipes.  Had the heads cut and the motor ported slightly.  Fast trail sled.  Good Luck.

 

[hpzrt600]

Put back in 35-40 pilot jets for sure-that's way to lean for that sled. Then set the idle air screws at 1-1 1/2 turns out.

Your throttle sensors-all you need to do is disconnect each carb sensor and jump each individual connector together to complete the circuit. Easy fix.

Run 340 jets. That is way safe for below zero weather. P-2 needle jets(stock). If you run the 35 pilots, then I would raise you jet needle one position richer(move the clip down one position) so you dont run too lean in the midrange. The midrange on those is a little lean and I would do the clip position myself-it really helps out the midrange lean problem.

Get a stock silencer back on the sled-there is nothing wrong with the stock one-they work just fine.

As for the cylinder running colder-check to see if your carbs are in sync. I'll be willing to bet that they aren't. That right there will make a cylinder run colder or hotter than another cylinder. They have to all be at the same slide position at idle(I check this with a drill bit end to set the throttle valve height equally across the board). The you have to check to see if they are all opening at the same time-if one is opening first, then the others follow the cable are out of adjustment. You also need to make sure that the carb slides are opening all the way at wide open throttle as well-if not, you need to adjust the cables accordingly to fix that. The throttle valve on the ENGINE side needs to completely clear the carb bore-dont set it to the airbox side-the airbox side goes up in the carb before the engine side of the slide does.

 

[JR ZRT600]

Thanks guys! This gives me some direction. I was wondering if the hacked box might not be providing enough back pressure resulting in low - mid rpm bog. I'll definately change the pilot jets to the 35 or 40 depending on what performs best. I'll also try leaning out the main jets and see what I can get. The carbs are in sync. That's why I was baffeled at the headaches I was having with the cool cylinder. I've got lots of time to work / tweek on it as all I see outside my window is grass again.

JR

 

[ZRT600MtnCat]

Your best bet is to Buy The Service Manual from Arctic Cat.
Get rid of any hacked parts, especially a hacked resonator.
Set the sled up the way it came from the factory by the specs in the book.Then tune it.   I am at 1000 Ft. ASL and I have 370 mains and it does not blow up. I may try 360 mains but the chart in the book says that could be risky if it gets to -10 or lower.As for the helix, that is an odd degree for a helix. mine has rollers so it is different, but factory 1998 zrt 600 uses 55 deg.This is why I say Buy The Service Manual.
My sled had a similar bog when I first got it. The Ice-Up switches were bad.

 

[SLDRDR]

I would stick to hpzrt600's advice.  I would also see a dealer about the recalls.  I bought a 96 zrt600 new and before christmas i had 1000 miles on it and i exploded 2 pipes and broke two motor mounts, i believe it was the front clutch side motor mount..All this was susposed to be recalls but i beat cat to it i had too many miles in before i was notified about the recalls.  Cat did cover all the expensives, i even got a belt out of them when the motor mount went.  When the motor mount went i was on the throttle in a corner and the sled got really noisey.  When i stop to inspect i found that when i hit the throttle the engine would flex so much that the pipes would come right out of the manifold flanges.