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Discussion Starter #1
I have been slowly chasing some issues with my Wildcat and I am looking for a little more help to get it tuned in just right. I will try to keep the descriptions to a manageable length.

Issue 1
After the post purchase cleaning of the carbs, I was running rich in the mag side carb. We switched the 2 carbs and the problem followed the carb to the other cylinder. Switched both carbs back and re cleaned the mag side carb. The issue went away for a few days but I let it sit for a few weeks due to closed trails. Took it on a 20 mi trail ride and fouled out 2 plugs in the mag cylinder. We then removed the mag carb and replaced it with a carb from my parts sled, plug fouling issue gone. Now I am struggling to get a proper burn in the cylinder. The spark plug in the mag side is dry with a gray black look to it, and the PTO side is a perfect golden brown. Carbs are jetted the same and the air fuel screws are both set to 1.5 turns. Not sure what could be causing this. I will be testing a different coil tomorrow and possibly a CDI box to see if it is a spark issue. Could it be a reed issue?

Issue 2
I am not getting the RPM and top end out of the sled. I can go 0-60 in an instant but I top out at 7000 rpm and can slowly build to 80mph but no faster. It came with a new Comet clutch set up with 54.6g weights and a yellow green spring. We tried swapping weights from the parts sled which were 51.6g. This didn’t seem to have an effect on the top end when we ran it down the trails. The clutch engages at around 4300rpm. We also tried swapping secondary clutches off the parts sled. Both didn’t seem to help the issue. They both have yellow springs, but the original one was set on the softest setting and the 2nd was right in the middle.

Could the issue with the top end rpm and power be related to the inefficient burn in the mag cylinder? Has anybody experienced these symptoms? My friend and I have been slowly checking things off the list to try, but would like to speed up the process if possible. Any help would be appreciated.

 

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Check your choke settings. Look make sure something didn't build a nest in the pipes. Maybe that is causing it to lose top RPM not able to breath. Hows your drive belt setting in the secondary. Is the primary clutch cleaned up no wear issues. Track drag how tight is the drive line??
 

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What about a new fuel line in the tank was that ever changed?? The get old and soft and will suck shut on load starve you for fuel.
 

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For issue #1, it seems as it it's actually now a little on the lean side if the plug is greyish.
Issue #2
When you put the belt on, is it flush or slightly out of the secondary sheaves?
 

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Discussion Starter #5
Wildcat Update

Had a chance to tqke it out quick tonight before the weather turns too warm the next couple of days. I swaped out the coil with one from another wildcat and took it for about a 10 mile ride. Checked the plugs about 6 miles in and I did not see visual improvement on the spark plugs. Still golden on the PTO and black on the mag side. I mistakenly described it as greyish, but it is actually black. I will take a pic of the plugs next time I check them.

The power seemed to improve with the changing of the coil. I was able to get it up to 7600rpm and pull about 85-90mph. It seemed to pull a lot better on the top end with just the coil change.

My belt is sitting just a little above the sheave on the secondary clutch when I put the belt on.

I will be looking into possibly not getting enough fuel in the next couple warm days, as well as do a compression test. Today when I held it wide open I would fly for about 20-30 sec and then it would noticeably lose some RPM and dog a little. There is an aftermarket fuel filter in the line I will make sure is not plugged and I will check the gas line in the tank. I know it is and old one and it is cheap to change over.

Thanks for the suggestions and I will keep you posted on what I work out.
 

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Check the choke and fuels lines like said above,also look at your secondary clutch,is the spring in it old-original? They sack out over time and will allow a quick up shift and can bog the engine.
 

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Discussion Starter #7
I have yet to change the fuel line in the tank, although I know for a fact it is old and soft and should be changed.

I got out and rode last weekend for 55mi and I think I got a bigger grasp on what is actually going on. Cruising through the winding trails at 20-40 mph it has the power like I believe it should. There are 2 things that happen in open fields that tell me it is a clutching issue some where. If I get to an open stretch and pin the throttle I will pull 7600 rpm and will push up to 85-90. If I am cruising through a field at 50mph then pin the throttle, I will max out at 6000rpm and about 60-70mph. If I release the throttle and let it coast down a little, then pin the throttle again I can get the revs back to 7600 and go fast again. I would assume I have a sticky clutch somewhere, would this be a secondary issue? Could a too soft spring give this feel?

When I get done riding from a longer haul the clutches are warm/hot, but not burn your hand hot. I also have a thin layer of belt "dust" all over the PTO side of the motor. I was told by someone your clutches should be fairly cool to the touch when done riding. Could they be misaligned? How you you check alignment?

Thanks for all the tips and hints, the sled is steadily getting better. Progress isn't fast, but I am excited by what I am learning and the help is greatly appreciated.
 

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The excessive belt dust does indicate a misalignment.
That engine should be hitting and holding 8k rpm at 6k+ you're just getting into the power band.

I'd take both units apart and clean them and inspect the weights for worn bushings and the rollers for flat spots or worn bushings.
The secondary could probably use a new spring if it has never been changed and the center shaft probably needs cleaning too.
Check the moveable sheave for wobble/binding, if it does then the bushing may need replacing.
 

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Did you switch the plug wires over from the brown plug and did it straighten out the mag side. Whats the compression of the mag side. When you have a stock motor with everything known the clutch is like a little dyno. Stock weight runs top rpm if you lighten the weight and no change your not making the power. If you cant run top rpm with stock weights low power. First step compression check on the mag side. Then pull the cylinder and check the reeds and piston and rings
 

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Discussion Starter #10
My last ride before the trails closed was very interesting in reguards to possible issues going on. I tore down the secondary clutch and cleaned it up really well before I went on my ride. It was still dogging quite a bit, and has been progressively getting worse through the season. Rode about 30mi and slowed down for an intersection and when I hit the gas the sled backfired and started stumbling. Shut it down ASAP to check things out, but all I saw was a big black spot in the snow and carbon spray (10-15 ft) from the tailpipe. Idled fine after 1 pull, but chugged when I gave it gas. Had a buddy lift the track off the snow and then it ran fine under power. Hopped on the sled and it took off like a rocket. Still not getting a complete burn on the mag side and not full RPM, but my power is back till about 80-85mph. Still running rich on mag side after backfire, even switching plug wires doesn't help. Would this cause a rich condition if there was too much back pressure in one pipe? Has twin pipes to a single can.

Teamgreen2, what is the best way to clean out the inside of the pipes? Pretty sure you were right, there is something blocking them but not sure how to get down inside to clean them.

Plans for the summer.

1. Remove head to check cylinders, pistons, rings, reeds, etc; and replace as necessary.
2. Replace the fuel line in the tank.
3. Go through the carbs again and replace needles and seats.
4. If I have time, swap a 95 ZR rear suspension.
 

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Take them off and use a section of chain to hang inside and rattle it around to loosen anything that may be adhered to the walls.
If it has an obstruction, some flexible cable will usually poke through it and then you can burn the rest out over a fire.
 

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You can try and fish a stiff wire through the pipe. Best way to clean out a mouse nest is heat. Put the pipes and can in a camp fire. Or take a torch and heat it up hot burn the stuff out of it. dont get to carried away you melt a hole in the pipe but if you get it cherry red up and down the pipe it should clean the stuff out. Do it outside its going to stink it will burn your carbon at.
Other thing on your bog check make sure your motor mounts didnt break or something that will cause a shift in your gear on your clutches that motor flopping around. My 650 I got someone made a torque bracket out a angle iron and bolted to the bulk head in front with a adjustable stop. My 650 isn't stock though I think it was a mod stock sled at one time. Its hogged out on intake and exhuast. plus has aftermarket pipes ported and polished and 44mm carbs.
 

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Discussion Starter #13
New Season, More Issues

I realize my posts are pretty long so I will provide a short summary at the beginning. I try to include all the details of what happened to paint a better picture for anybody trying to help. Maybe a random detail will raise a flag with someone that knows more about sleds than I do.

Summary
Sled was a bit doggy upon startup. started to get a little worse as warmed up on the trail. Turned off at gas station 5 mi into ride and was dogging so bad when restarted it would not move. checked spark, new plugs. Removed drive belt and still did it, must be something in the motor, not sure what it could be.


This summer I took a few suggestions from previous posts and worked on a few things.

I burned out the exhaust pipes over the hot coals of a camp fire and then ran something inside to knock off all the ash that was left over.

I replaced the hose from the oil tank to the pump as it was leaking a ton of oil.

I installed a new fuel line inside the tank as well as a new inline fuel filter.

2 days ago I finished putting everything back together, cleaned the carbs and fired it up. I did a handful of loops in my friends yard and it seemed to be running great, was idling a little low 1500, but couldn't wait to get it out on the trails.

I fired it up yesterday, 2 pulls, i did a couple loops of the yard it seemed to have a little dog in the throttle when you punched it hard. It seemed to work itself out and we took off to the trails. In the open fields it would shoot right up to 80 and it would build speed after that pretty steadily. About 2 miles in it was getting a little doggy again, but more around idle. We pulled in for gas and when I started it up again it seemed to idle ok, but when I hit the throttle, completely dogged and would not even move the sled. checked the plugs, one looked fouled, changed it, same result. Checked the spark, looked good, tried to dry both cylinders, no changes. It is just a bunch of exhaust smoke and that motor bogged down sound. (Baaaaaa Baaaaa). It backfired a couple of times, but unlike last year no black smut cam out the exhaust pipe. Towed it back onto the trail, the track was spining as we towed it so it was not locked up. We removed the drive belt and fired it up and had the same doggy problem. This tells us it is somewhere in the motor, not the drive terrain. Came back and picked it up 4 hours later, fired right up and drove no problem up to the trailer.

What could cause this problem on warmup? Stator, coil, Ignition Module, or is it something mechanical in the motor? Any advise would help, starting to think I am cursed. I dunno
 

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Discussion Starter #15
The PTO Side was fouled, last winter it was always the mag side. When I changed it out it did the same thing. Both plugs after that were always soaking wet, almost as if there was too much fuel or oil, it smoked quite a bit while it was dogging.
 

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Discussion Starter #17
The pulse lines on my sled are solid rubber, so I would have to remove them to see if there were fuel in them. I assume I would have to warm it up again and get the symptoms to repeat before I check those lines? Would I get these symptoms if I were getting fuel sucked into the bottom of the crank case through the impulse lines? I will check that when I get a chance. I don't have a heated garage so I need to wait till the temps up north here climb back out of the basement, maybe Saturday if I am lucky.
 

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Exactly, that is why I asked.
Because if the pumps are leaking into the base it will act as if it is flooding and nothing you do with the carbs is fixing it.
 

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Discussion Starter #19
Thanks for the tip, I will have to try that today. I will run it around and try to get it to repeat the phenomenon, maybe see if I can some video of it running like that. I will keep you posted on what I find.
 

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it still sounds fuel related to me, who has been tuning your carbs? also check your plug wires for any defects. and a new set of plugs would be a good idea.
check the compression also.

i think you need to get the carbs tuned correctly before anything, get it idling at the correct rpm, then go from there.
 
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