Arctic Chat

macgyvr · 02-06-2011, 10:55 PM

the position that your choke is in at around :47 seconds into the video is the on position not the off position and with the choke on after you start the motor and it warms up the rpms should climb that indicates to you that you can turn the choke off which should put you back to down to the idle rpms now not having an airbox in my opinion is going to affect how that all works you could try rubber banning a small rag over the piece that comes from the carb to help maybe simulate an air filter because honestly once you get this thing runnin good with out an airbox and you put an airbox on you might have to go through the whole process again to make it run right

gdvross · 02-06-2011, 11:00 PM

I have a 98 454 4x4 and i'm pretty sure te choke is off in the up position.Like you i'm having carb issues took it out in the cold and it would not run .Going to check the carb out again. thanks for the good vids they are helpfull.

stevewatr · 02-07-2011, 06:29 AM

Quote: Originally Posted by gdvross

I have a 98 454 4x4 and i'm pretty sure te choke is off in the up position.Like you i'm having carb issues took it out in the cold and it would not run .Going to check the carb out again. thanks for the good vids they are helpfull.

Your Welcome. I hope to post all the videos I've made detailing the trials and tribulations I have gone through to rescue this machine from the trash pile.

stevewatr · 02-07-2011, 06:41 AM

Quote: Originally Posted by macgyvr

the position that your choke is in at around :47 seconds into the video is the on position not the off position.......

Okay, now I see my big problem, I am running this thing with the choke on all this time, that would explain it running too rich. I guess the fact it revs up when I turn the choke off means I need to reset the idle, and pilot screw adjustments. I understand about the lack of an airbox changing the flow characteristics, and am on the hunt for one. In the mean time I will try to set it up to run decent the way it is. Wish I had noticed that tiny arrowhead on the end of the choke lever a while ago. Also wish I had not miss read the explanations given near the start of this thread about what position is on/off.

stevewatr · 02-12-2011, 09:53 AM

After learning how the choke works, I was able to shut it off, bring the engine idle adjustment down, and readjust the pilot air screw. Was running well, but still hard to start, but this was apparently solved by replacing the spark plug. There was an old Tech Service Bulletin describing a fix for poor starting in cold weather. It involved a carb kit, part number 0437-0088, it is NLA, and the dealer I spoke to does not know what it contained. He speculated it involved resizing of jets, and said re-jetting with an aftermarket kit might be a comparable change. The second thing recomended was changing the spark plug to a new number, 0217-632, this crosses to an NGK CR6E. The plug that was in my motor was a CR8E, and that is what NGK's online cross reference says to use, but I suspect the cross reference is going on the original data supplied by Arctic cat. So what's the difference between a CR6E, and CR8E? For starters, the gap. The CR6E is gapped .028 vs. .030 for the CR8E. but the reason I believe they called for the change is the heat range of the plug. The CR6E is a "hotter" plug. I'm not going to go into the tech detail about what this means, suffice to say this plug "runs hotter". NGK has a great section on their website explaining sparkplug heat range, and other great info. Here is a link:

NGK Spark Plugs USA

It is also interesting to note that the Cat 500 that replaced the 454 in 1998 still used the CR8E, but in 1999 changed over to the CR6E.

Here is the latest video showing my 454 running with the new plug installed:

YouTube - Arctic cat 454 carb issues Part 13

OH, I almost forgot, the third part to the recommended changes to improve cold weather starting was adjusting the intake/exhaust valve clearance. Sorry I do not have those specs, but if I decide to try it at some point, I'll post the info.

Regards,
Steve W.

gdvross · 02-14-2011, 10:08 PM

I did find out what the problem with my bike was .When trying to get at the carb I found that the fuel line was plugged. The tank has a 3/16 hose barb and the carb has a 1/4" barb.I wanted to put fuel hose on that can be seen through, so it took a little longer but it ran great the other night. Think I might try out the hotter plug for cold starts. Thanks for the info.

stevewatr · 02-15-2011, 07:39 AM

Quote: Originally Posted by gdvross

I did find out what the problem with my bike was .When trying to get at the carb I found that the fuel line was plugged. The tank has a 3/16 hose barb and the carb has a 1/4" barb.I wanted to put fuel hose on that can be seen through, so it took a little longer but it ran great the other night. Think I might try out the hotter plug for cold starts. Thanks for the info.

Your welcome. Spent the weekend on the ice, pulling a sled with my kids on it. Seems to be running well, only issue I had was a few times while idling, it would suddenly "cough", almost like a backfire, and die. This was very sudden, and would only happen at a low idle. It also happened only a few times, and restarted immediately just fine, so I'm not going to worry about it until I get a new air box and filter on it, and readjust the pilot air screw.

Utah Red · 03-18-2011, 09:37 AM

Hi guys. Newbie here and this seems like a logical place to start. I have a '98' 454 that I am having a few carb problems with. Needle valve was sticking and dumping all the fuel. I pulled the carb and cleaned the needle and seat (and screen) but am totally confounded with the choke cable as I cannot figure out how to disconnect it from the carb body. I managed to get the plastic nut holding it in undone but cannot, for the life of me, figure out how it disconnects. Anybody have any suggestions?

Hope this bumps up with a new post....

stevewatr · 03-18-2011, 08:17 PM

The "choke" on these carbs is a small brass plunger, that gets moved in/out via the cable. Once you unscrew the plastic nut, the whole mess is supposed to slide right out. I say supposed to, because if yours was free, you would not be posting the question

I suspect your little plunger is stuck in there. Since the needle was sticking, its a safe bet there is varnish gumming up other parts, like the plunger. With the nut unscrewed, gently pull outward on the cable sleeve, while moving the choke lever, this should allow you to get enough space to get a small straw applicator of a can of carb cleaner in there, and give it a good shot of the stuff. Wait a few minutes, then try to pull it out via the cable.

Check out this video, It's part of a longer series I'm working on, but I posted this raw footage of the choke mechanism:

YouTube - VID00022.AVI

Utah Red · 03-19-2011, 08:45 AM

Thanks, Steve. You're the man...

Been years since I worked on Mikunis so this configuration had me going when it wouldn't come apart. I'll give the carb cleaner a try. The little slide doohickey is stuck good so I hope it works.