Ok. Have a raptor that runs pretty good. After sitting for 3 months in the winter, it developed a problem. If it is idling for any amount of time or running very low RPMs and you give the throttle the slightest push it will die. If you crack the throttle to anything above 1/4 it might stutter for a split second, but revs up fine. Also, the idle seems to fluctuate, after you rev it a couple times, the idle is fast, and then slowly slows down to a low idle and will stall every now and then. I have played with the idle screw and found that the idle goes as follows.
Low (stalling)
Low (stays running barely)
Slow normal Idle
Normal Idle
Fast normal Idle
Slightly slower normal
Slow Idle (starting to miss and stumble)
Fast Idle
Very Fast.
You can see that something is not right with the carbs. It has run a little rich since I bought it (mods are K&N, Gutted WB R4 Slip on). Never gave me any problems at sea level but riding up in the mountains would make it run very rich and give black smoke.
Runs good otherwise. Lots of power.
I just set the valves and put in a new plug, the old plug was darker than tan, more of a brown but it didn't have oil or deposits on it.
I'm thinking I need to clean out the carbs and possibly rejet. I'm not sure what jetting is in there (stock needles or what).
Maybe the pilot jet is plugged?
Any advice on what could be the problem would be appreciated.
Your description really indicates a partially plugged pilot jet(s). I would clean them out and run some wire through the pilots or replace them all together with new ones especially if it has sat over the winter. Bikes that take mix can sit longer without gumming up but bikes like the raptor that take gas only will tarnish up after a month or 2 without some additive. I try to turn my petcock off and let the carbs empty out until it dies to lessen the amount of gas in the bowls.
The reving at idle is a lean condition and most likely caused by a plugged pilot.
With a K&N, Open lid, and slip on I run 160/165 mains and 25 pilots, 3 turns out on each air/fuel screw. Some go 2.5/3 on the air/fuel
I agree about the pilot jets. Revving could also be a vacuum leak. No one cleans the raptor carbs because of the time and effort involve. I clean my friends 2004 and it runs perfect now.
make sure your choke plunger is working correctly. sometimes they gum up after sitting. look at the underside of your choke pivot and make sure the cable is going in and out, not balling up right there. OR, you can unscrew the plastic nut where the cable goes into the left carb. pull the spring and plunger out and make sure they move smoothly and freely. I've seen this plenty of times. Hope it is this simple! :tup:
Ok. Took the carbs off. Choke is functioning properly.
When I changed the plug it was dry but dark brown. Indicating a rich condition.
I checked the jets, 144 and 146 mains with 22.5 pilots. The needles appears to be stock (no markings on it) and both are in the 3rd position (I'm not sure whether you count from the top or the bottom but it's in the middle).
I pulled out the mains, pilots and the one other (start up jet???) and have been blasting them out with compressed air, the pilots seemed to be a little restricted by something, but cleaned out when i shot air through them.
Im just about to measure up the floats, you measure 13mm from the bowl/carb split to the shoulder of the float oppositre of the float pivot point??
Does the jetting sound right? I live about sea level, have a gutted WB R4 slip, and a K&N with airbox lid ON.
Since the plug indicates rich should I move the clip one notch up?
I am planning on going back to stock air screw settings 2.5 i think??
What? Thats a pretty brasen thing to say man. I'm a member on both sites and would say they are equal in knowledge about carbs or anything else. It just really comes down to who is online looking at the new threads to get an answer.
Reset the floats to 13mm, put the carbs back in with the clear tube and it is about 10mm over the float bowl split line. This is with the carbs sitting in place and the quad on flat ground.
I had been noticing a stumble when the bike was on steep hills so obviously it must be too high. I've never seen anything come out of the overflow but I haven't been looking either.
Going to set the floats at 15-16mm and see where that leaves me
Floats set at 15mm, clear tube shows 3mm above split line. Now I just have to wait till after work tomorrow to go for a rip. It fired up but i haven't had a chance to ride it.
What? Thats a pretty brasen thing to say man. I'm a member on both sites and would say they are equal in knowledge about carbs or anything else. It just really comes down to who is online looking at the new threads to get an answer.
i guess so, maybe they just dont like me here, i had some carp probs, one person responded asking if checked the plug, no one else so i went there and got a lot of help from them.
i mean its not like it hurts my feelings i just needed some suggestions and they had a lot more ideas and that is how my opinion was formed. i hate carbs and i havent sovled my problem but at least i know what is not wrong with it hehe
So here's a little update. Port matched the intake boots and moved clip to 3rd position. Plug was black on the 4th position.
146/144 mains, 3rd clip position, 22.5 pilots, and still working on dialing in the fuel screws. Its getting a steady idle and no popping on deceleration the best way to fine tune this?
Hey, common issue. I ride a 03 raptor 660.
1. make sure your parking brake is off when revving. there is a rev limiter.
2. ensure the carbs are clean and your floats are set.
3. google raptor 660 rev limiter. I had to wire up to by pass the reverse rev limiter. good luck.
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Blue Traxx Forum
850.3K posts
44.6K members
Since 2001
A forum community dedicated to Yamaha ATV owners and enthusiasts. Come join the discussion about performance, modifications, classifieds, racing, maintenance, and more! Open to Banshees, Raptors, Blasters, and others for recreational riding and racing.