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Discussion Starter #1
Hi all,

Thanks in advance for any help you can give. I'm completely stumped right now. 2005 Kodiak 450, it had been sitting for some time. Put a new battery, fresh fuel, cleaned carb completely including all jets and passages. Started up but could not get idle to stay still. Backed idle down, it would die, rev it up, it would rev uncontrollably then finally idle back down after messing with idle screw--then die out unless you touched throttle. Figured I missed something in carb, tore it down 2 more times, same issue. Also doesn't like to start well with airbox lid on. Bought a brand new carb and air filter---figured it would be good to go....nope....same issue. Checked valve lash, they were a little tight but not bad....no difference noted. Sprayed carb cleaner around entire carb area including carb boot to check for leaks, no difference in idle.....I'm at a loss right now. Please offer some help! Also what should be compression on this bike?
 

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Did you put the pilot needle in the same position (same turns out) as before? It's 2.5 turns out from seated position on your 450.

Is the vacuum slide diaphragm in good condition and in proper place under the metal cap?
 

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Discussion Starter #3
Did you put the pilot needle in the same position (same turns out) as before? It's 2.5 turns out from seated position on your 450.



Is the vacuum slide diaphragm in good condition and in proper place under the metal cap?


It’s a brand new carb so I assume the slide is fine. Not sure on turns of pilot being it came all adjusted but with the old carb I did 2.5 turns and still had the same issue


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Did you check the carb to engine boot? could have a crack or tear... Leaking air.
 

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Hi all,



Thanks in advance for any help you can give. I'm completely stumped right now. 2005 Kodiak 450, it had been sitting for some time. Put a new battery, fresh fuel, cleaned carb completely including all jets and passages. Started up but could not get idle to stay still. Backed idle down, it would die, rev it up, it would rev uncontrollably then finally idle back down after messing with idle screw--then die out unless you touched throttle. Figured I missed something in carb, tore it down 2 more times, same issue. Also doesn't like to start well with airbox lid on. Bought a brand new carb and air filter---figured it would be good to go....nope....same issue. Checked valve lash, they were a little tight but not bad....no difference noted. Sprayed carb cleaner around entire carb area including carb boot to check for leaks, no difference in idle.....I'm at a loss right now. Please offer some help! Also what should be compression on this bike?


This was happening to me on one of my 3 wheelers. It ended up that there wasn’t enough fuel flowing into the fuel bowl. Basically the fuel in the bowl of the carb was being consumed at a faster rate than it was being replenished. This will create a lean condition in the engine which is exhibited by high rpms. Sometimes a quick way to test this is to put the choke on. This essentially enrichens the fuel mixture reducing the lean condition. If it runs better with the choke on might need to get into the carb and check the needle and seat valve. However, before you do anything, confirm that you have free flowing fuel from the tank to the carb.
Good luck
 

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Discussion Starter #7
This was happening to me on one of my 3 wheelers. It ended up that there wasn’t enough fuel flowing into the fuel bowl. Basically the fuel in the bowl of the carb was being consumed at a faster rate than it was being replenished. This will create a lean condition in the engine which is exhibited by high rpms. Sometimes a quick way to test this is to put the choke on. This essentially enrichens the fuel mixture reducing the lean condition. If it runs better with the choke on might need to get into the carb and check the needle and seat valve. However, before you do anything, confirm that you have free flowing fuel from the tank to the carb.
Good luck


Fuel flow is good. Took fuel valve out and blew all ports out. It’s a brand new carb and it’s doing the same thing the old carb did so I really don’t see it being a carb issue. I also replaced the coil just in case it wasn’t firing properly, that did help either. It takes a long time to start, have to hold throttle open full and once it starts, it’ll rev up good, but seems to take a long time to idle down then all of the sudden it lowers so far down that it tries to stall. It has a mind of its own. When starting it does smoke a bunch through the air box. Im at a loss right now. Haven’t had one I haven’t been able to figure out before


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If a vacuum leak is small, it can be difficult to test with carb spray.

Instead of Carb Cleaner, use starter fluid (spray) and test for vacuum leaks again. It is more volatile so be careful.
 

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Check that the throttle cable is sitting properly in it's holder on the carb.
Check that the cable isn't jammed on the frame somewhere, if the cable is jammed it can pull slightly on the outer cable lifting it out of it's holder, slowing idle return.
Check cable free play at h/bar adjuster.
Vacuum plugs not perished or missing.
And(the all time favourite) a broken thread(top or bottom) in the inner cable holding things up.
 

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Figured it out. Keep in mind that compression wasn’t horrible but after I kept seeing smoke coming into the air box, I decided to pull the head to make sure I didn’t have a possible valve issue. All looked good. Kept tearing it down and found the raised areas of piston in between the rings were broken. Luckily it stayed in place while in the jug and no damage was done to cylinder. Putting it back together and should run much better soon. Thanks for all the suggestions


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Figured it out. Keep in mind that compression wasn’t horrible but after I kept seeing smoke coming into the air box, I decided to pull the head to make sure I didn’t have a possible valve issue. All looked good. Kept tearing it down and found the raised areas of piston in between the rings were broken. Luckily it stayed in place while in the jug and no damage was done to cylinder. Putting it back together and should run much better soon. Thanks for all the suggestions


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Great job! Glad to hear you’re on your way back..
 
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