Stock bike, stock jetting, miss off idle.

[Penrod]

I just bought an 04 660 Raptor and after a few good days of riding I have found a few things that need work.

#1: There is a hesitation just off idle, It sputters and sounds like it wants to back fire. Just barely pressing the throttle I get the following idle.. its kind of like put put put put put poof spit put put spit sputter put put put put spit poof sputter. Pretty technical description eh? This is the most annoying issue I have found, it's impossible to start to roll without reving past 3/4 throttle or else it will stall when letting the clutch out. It's totally stock with no mods. I noticed the exhaust glowing around the head area but not bright red, you can't tell it's glowing unless it's dark.

I take it to be running lean, I have yet to do a plug chop or check for a air boot leak, maybe tomorrow if I have time. I don't have any popping on deceleration. It also has a bad hit when I go from no throttle slowly through the throttle while rolling. It has no balls whatsoever and then BAM whiplash!

With stock exhaust and stock filter with lid, why would this thing be acting like this? It would almost have to be a leak unless they come from Yamaha like this?

#2 There is a clicking noise coming from the front left wheel area or at least that's where it sounds like it's coming from. Is this normal or something going bad in to the front end? It's frequency follows the speed the bike is rolling, not engine rpm.


Can I do a plug chop test on a used plug, or do I need a new one?

[Peelz]

could be many things:  One carb is not getting fuel. Stuck FLoat... hmmm Does the idle get better when you choke it? That might tell you if you are lean. Bad gas? Also 660's occasionally had trouble with the intake boot between carb and head slipping off, and sucking too much air. Mine had that. I retightened it, and added some safety wire to stop it from slipping.

Have you had the carbs apart? Could just need some cleaning up. 

ALso, check idle A/F screw could be closed too much, or open.


I like the technical description of the idle. Are you totally sure somebody didn't sneak a harley motor in there. Sounds crappy like a harley. 

[AJ RAPTOR]

could be many things:  One carb is not getting fuel. Stuck FLoat... hmmm Does the idle get better when you choke it? That might tell you if you are lean. Bad gas? Also 660's occasionally had trouble with the intake boot between carb and head slipping off, and sucking too much air. Mine had that. I retightened it, and added some safety wire to stop it from slipping.

Have you had the carbs apart? Could just need some cleaning up. 

ALso, check idle A/F screw could be closed too much, or open.


I like the technical description of the idle. Are you totally sure somebody didn't sneak a harley motor in there. Sounds crappy like a harley. 

they can also pop the intake boot off the carb on the airbox side mine did now im getting another set of carbs a fix i did for this was drilling the boot and the carb where the boot goes on the carb and screw them together with a little screw they wont pop off again

[Penrod]

could be many things:  One carb is not getting fuel. Stuck FLoat... hmmm Does the idle get better when you choke it? That might tell you if you are lean. Bad gas? Also 660's occasionally had trouble with the intake boot between carb and head slipping off, and sucking too much air. Mine had that. I retightened it, and added some safety wire to stop it from slipping.

It idles fine...The put put is when I just barely give it some throttle it starts sputtering. Gas should be good, ran it bone dry and then filled it up at the pump. It ran the same on the old gas as it does the new. I will get some ether tomorrow and see if it's leaking around the boot.

Supposedly the carbs had just been cleaned before I bought the bike. This is the same bike I posted in the "Should I buy this raptor" thread. Everything is super clean on the outside but I know that doesn't mean it is on the inside. Maybe the guy that cleaned them (PO took it to a shop) didn't get something right on the reassembly..

I did notice it wanted to keep a high idle after I got on it pretty hard today. So hopefully it's just the boot leaking, because I don't really want to get into troubleshooting this soon after buying the bike.

Thanks for the help guys.

[Peelz]

right off idle, the mixture will be controlled by the pilot jet. Clogged pilot jet..Not sure what else it could be... I am drawing a blank here. It does run high rpm well? hmmm expect a visit from a guy named Mad Dog. the 660 guru who will probably have completely the opposite advice I have. 

Oh, a correct plug reading should be done with a new plug, if possible. Old plug will show the wear from previous riding.

[Penrod]

Ok guys I have messed around off and on with this thing over the last two weeks trying to get this problem solved and I feel like I'm close.

Last weekend I pulled the carb's and cleaned everything! Blew everything out checked the float levels, 13mm and 14mm and put it all back together. Changed the plug and started it up and it had the same exact miss.

I ended up pulling them again this weekend since the right float kept sticking and dumping fuel from the overflow. I found out that the left floats needle valve had an issue while I had it apart. The little spring loaded bumper that rests on the float tang was frozen, fixed that last night and put it back together again this morning. I also turned both a/f screws out three turns and tried it again.

It seems to idle better and the miss is very spread out and it doesn't miss every couple strokes like it did before. I started it with all the plastics removed so I could get to the carb's and adjust the a/f screws.

After it was warmed up the idle sounded MUCH better but as soon as I gave it a tiny bit of throttle the miss came back! I put my hand over one side of the snorkel that runs to the airbox and it fixed the miss completely. By reducing the air, I richened up the mixture correct?

I have read several places that more then two turns out on the a/f screws means a bigger pilot jet? The stock pilot jets are 22.5, would a 25 pilot be my savior?

[Peelz]

bone stock shouldn't need anything... but yes, effectively, you were choking the intake, making it rich.

[Penrod]

I pulled the carbs again and turned the the screws out 2 more turns. I think I misunderstood the more then two turns out change jet deal. I'm thinking it was start at three turns out, and then no more then 2 more or you have to change the jet.

Currently they are turned out 5 turns total and the miss is still there right off and I mean RIGHT off idle. Choking it with my hand makes it go away.

[Peelz]

the screws should be 2-3 turns out in my experience.

BUt it runs good when revving? Move needle clip down one spot. I had to do that.

That larger 25 pilot you mentioned could help.

Other than that....spark issue maybe? Weird. DOes it do this when in gear, or just revving?

[Penrod]

It does it in any gear just as you get on the throttle but its most noticeable when your try to get moving from a stop.. If you don't rev it past 1/4 throttle it will chug each time it sputters and it usually stalls.

It runs great and if you rev it quickly from idle to WOT there is no hesitation, only the miss when you slowly apply throttle from idle to 1/4 throttle. Everything past that point is great.

I'm going to take it for a ride here in a little bit and I will let you know how it does...


Thanks for all the help man.. I really do appreciate it. Maybe here before too long I won't be embarrassed to show it off. lol

[Spartan]

Don't be embarrassed...some of these guys have blue/white quads...talk about embarrassing

[Penrod]

Don't be embarrassed...some of these guys have blue/white quads...talk about embarrassing

LOL I'm not one to get embarrased about what color quad I ride, if it has wheels I will ride it. But it has to run good!

My ride got cut short by rain but I'm satisfied with it now. I got it into some tight 1st gear stuff down by the river and it never stalled on me, except that one time when I was in reverse... I even got a little mud on it 


Thanks guys for all the help!

[Peelz]

Don't be embarrassed...some of these guys have blue/white quads...talk about embarrassing

07 se's are moderately less embarrassing than 08 se's