05 AC 650 V2

I put an HMF Utility series pipe on it and also put the 04 snorkel on it instead of that nasty 05 setup. 122f/r jets

Seems to run good mostly, however once in a while it will act like I flipped the kill switch, if I back off the throttle or get on it more, it kicks back in.

Thoughts?

 

Does the mixture screw and needle position need adjusting from these mods?

 

Its probably jetting.
It all depends on what the throttle position is when the bog happens. Is it right off idle?
Seems to me the front carb is usually jetted richer on those motors, than the rear carb.
Heres a good article on jetting, and it lists the symptoms of lean and rich at the end of it. It might help you figure out whether youre rich or lean.
jetting

 

OK, from reading that article, my first guess would be that my needle is lean. Are the stock needles adjustable?

 

The older carbs have 4 or 5 notches to lean or richen the high speed mixture without a jet change. But as of 2005 AC followed Kawasaki's example and bought the cheaper carbs without the adjustable needles. So it's either different needles or jets or both. Ain't owning a Kawasaki designed wonderful.

 

so where would I find myself the required needles?

 

You get them from either Arctic Cat or from a Keihin (that's who makes the carb) carb dist. or dealer or from one of the many aftermarket parts dealers. I would contact HMF about what you need to do because with your changed air inlet set up it has changed things. I would suspect that you will need jetting for an '04 650 with your pipe rather than an '05 due to the air inlet change.

 

That is basically what we did. According to the deal, stock jets for an 05 are 115's and for an 04 they are 122's. I am running the 122's now, and it seems to be good in the main, but I need a little more juice in the needle area. I don't think I gained much with the different snorkel except getting a few inches deeper without taking in water.

I'm carb stupid, so forgive me, but would a needle shim be the trick? or do I need to go the other way?

 

Nothing to be forgiven, This is how you learn. The carbs are different from '04 to '05 (part number change), so a jet change to the '04 parts may well be a mistake. I still think you should contact HMF and ask them if the pipe requires different jets. After you get they imput you can do some testing yourself. Make a high speed run and when the motor stumble, turn the key off and roll to a stop. Pull both plugs and look at them. You need to know what is going on in the motor in reguards to fuel and air mixture when the problem occurs. White plugs tips means to lean (I suspect this is the problem and dangerous to your engine) or to rich gives you black plug tips. A light brown to dark brown color is what you want. If you leave the motor running as you slow down you will wipe the true reading off the plugs.

 

i'll give it a shot, but it won't be a high speed run as it never happens when I'm really movin along. I think maybe 20-25 is the fastest I've been going when it has happened, and that may be too high of a guess.. And it only happens if I maintain speed for a bit.

The pipe does require different jets, but they don't have the info for the 05's. On the 04's they say go up two sizes. My stocks were 115's, and with the intake change we went up to 126's(127 maybe) first but that was way too rich. We bumped it back down to 122's and that seems alright. I will probably have to go down a size in the summer, cuz the 122's seemed just a smidge too rich, but now that the temp has dropped they are workin good.

Is Parts Unlimited a good place to start looking for the adjustable needles?