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Discussion Starter · #1 ·
I just purchased an 05 660r and I love it...the only problem I have is hesitation when I'm going along slowly and giving it the throttle slowly...it acts like it doesn't want to take the fuel like it should, but once I get past that certain point on the throttle...........hang on.....also sometimes it will backfire. Any ideas?...by the way your web site is great!
 

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Does it have an after market exhaust and/or air filter?
It only stutters and back fires when coming off the throttle, and from idle to about 1/4 throttle it feels like its lost power, stumbles then after 1/4 throttle it takes off like a bat out of hell.? Is or does that sound about right?
 

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Discussion Starter · #3 ·
exhaust and air filter stock....i cleaned the filter and replaced the spark plug...i only notice the hesitation from idle to about 1/4 throttle....everything ok from throttle to idle....thanks again.
 

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sounds like you may need to adjust your a/f screws on the bottom of your carbs. do you know where they're at?
 

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this is a bottom view of a single carb. you should be able to orientate your self. there is a slim flat head screw where it denotes #1. there is one under each carb and they are a pain to get to. Turn each one in about a 1/4 of a turn (clockwise looking at the screw, not behind the screw) and try out the bike. If it still stumbles ect, turn it in another 1/8 turn on each. Keep doing so until it sounds and feels good.
 

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If it feels like it got worse after the initial adjustment turn them the other way, its too lean...I suspect its too rich so you should lean out the mixture a little.
 

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Discussion Starter · #9 ·
that's a very good possibility that the mixture is too rich by the way the old plug looked...pretty black looking....i'll definitely give it a whirl.
 

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Discussion Starter · #10 ·
rt...........thanks for the advice..........worked great.......very responsive at any throttle now.....luv the raptor.
 

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Hey rt, i'm having similar problems with my 03 raptor. I let it sit all winter then fired it up this spring to find it smoking blue. I took out the carbs and cleaned them up, replaced the spark plug and air filter yet I'm still getting blue smoke. I keep playing with the throttle screw trying to find a good idle point for it but it's consistently sputtering whether in low idle or high idle. Should I try turning these screws in or out, and could that help my blue smoke problems?
 

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Also having exact same problem. If you just touch the accelerator slightly where the engine just begins to rev a little higher than idle, it starts sputtering, missing, backfiring, and eventually dies. No problems at mid or high RPMs though. Only about 25 hours on the bike total. Replaced spark plug and changed oil, no effect.
Purchased my Raptor from a guy in the high desart and brought it back to the valley where I live. Thought maybe the altitude change screwed up the jetting. The guy did have it sitting in his garage for a long time, and only used it like once a year. I guess it could be the carbs needed cleaning. Regardless...I broke down and took it to the shop...it needed its 25 hr maintenance anyway.
 

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busted knuckles, raptormonk, did you :
*change the gas in the tank?
*give the rappys an oil change, I recommend rotella synthetic (only one grade), and a supertech 6607 oil filter-both from walmart and very cheap, plus both are better than most other synthetics.
Now what mods do each of you have
After market or modded air box, no air box
after market exhaust-what kind, full system or slip on
piston size: stock, compresiion size, and typ
have a cam, stage 1, 2,3 ect
stroker crank init

or are both bikes completely stock? need to know these answers to get a good feel for whats going on with each.
 

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rt said:
busted knuckles, raptormonk, did you :
*change the gas in the tank?
*give the rappys an oil change, I recommend rotella synthetic (only one grade), and a supertech 6607 oil filter-both from walmart and very cheap, plus both are better than most other synthetics.
Now what mods do each of you have
After market or modded air box, no air box
after market exhaust-what kind, full system or slip on
piston size: stock, compresiion size, and typ
have a cam, stage 1, 2,3 ect
stroker crank init

or are both bikes completely stock? need to know these answers to get a good feel for whats going on with each.
Yes I have changed the gas in the tank a couple of times.
Yes I gave my bike an oil & filter change...Amsoil 0W-40 Performance synthetic.
Mods: My raptor has full LRD exhaust, Dyno-jet kit (not sure what its set to though--was set at a location of about 3,600 ft. above sea level--now its being used at 0 to 500 ft.), Proflow air modification w/ K&N filter.
Everything else is stock (engine isnt bored, no piston mods, etc.).

What do you think?
 

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you might have to upsize the pilot jets now that your altitude is lower (therfore more air density, requiring a little more fuel to achieve a optimal air/fuel ratio). But first-you can slighlty alter your "idle-1/4" throttle air/fuel ratio by the air-fuel screws mentioned-shown in the above conversations. Except, you going to have to turn yours out (couter-clockwise as if you were looking at the screw head on). Intially start with a 1/2 turn out on each side, then go 1/8 turns until it seems right. These screws can only be turned out so far before they don't do anything anymore. So if you turn yours out more than a full turn on each side, then going to a larger pilot size may be required.
Make sure your air filter(s) are cleaned before doing this.
BTW-amsoil is great :thumbsup:
 

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Check it out RT, when I purchased the bike about 2 months ago, the guy still had all the stock parts and mod accessory boxes. I found the Dynojet kit box he used. Looks like he had the DJ144 and DJ146's installed (he kept the little baggies in the Dynojet box), which is for 3k-6k ft, and like I said, im at 0-500 ft. All I probably need to do is replace the DJ144 with the DJ148 (the correct jet for my level) and adjust the air/fuel mixture accordingly, right?
 

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Good move on his part! But- before you start replacing jets; adjust the a/f screws first. If it runs good at full throttle and in the midrange, the needles and mains may not need to be changed out. My impression was that was where you were having problems as well.
 

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rt said:
Good move on his part! But- before you start replacing jets; adjust the a/f screws first. If it runs good at full throttle and in the midrange, the needles and mains may not need to be changed out. My impression was that was where you were having problems as well.
rt, naw, it gets really choppy just a hair passed idle...mid and high rpm are fine, its just the low rpms where its having problems. In fact, if I just let it idle it will eventually sputter and shut off on its own...might take a minute or two, but it does it every time.

I just read an entire whitepaper on jetting and carburetion. I read about the pilot jets, the Needles and Mains, attitude variants, gasoline variants, air fuel mixtures, and everything. It seems like everything has to be absolutely EXACT for the bike to opperate correctly. Which leads me to another question. Since the 700's use EFI, do they encounter the same types of problems...or rather, do they require similar adjusting depending on where you use them?
 

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to 700's automatically adjust for barometric pressure, humidity, altitude, temp change ect, they won't adjust to modifications to the engine..pipes, piston, cam,..ect, they need the equivalent of a fuel management system add-on...or roughly so.
Plus its not so much the rpms you should be listening for or focusing on, it the actual throttle postion you should be.
Divide your throttle stroke into 1/4's. The first quarter is managed by the pilots and fine tuned with the a/f screws, this circuit slightly over laps into the second circuit, the needles, they control from 1/4 throttle to 3/4 and slightly over lap into the mains, which are the last circuit and control 3/4 to full throttle.
If your on your quad and pressdown about 1/8 on the throttle or so those are the pilots working.
press down half way its primarily your needles doing all the work,..regardless of the rpm's.
Press down the throttle completely and those are your mains. what is happening is that at first the pilots are putting fuel into the motor, they don't stop when they go to the needles, now you have the needles and pilots putting gas into the motor, get into the mains, now you have pilots, needles and mains all putting gas intot the motor, its just at each individual circuit, when moving to the next becomes very miniscual, that it has very little effect.
Many wonder why with the same mains one persons bike could run rich and the others lean (under the exact same conditions).
Look at it this way both run 165/170 mains, one runs good, the other too rich.
the one that is running rich may have bigger pilots and have a higher needle setting which down the road would already have it at a rich setting entering the mains circuit, which menas those mains may need to be possibly stepped down to 160/165, but both motors are running at the same fuel consumption hp, just different a/f ratios throughout the curve, and different hp curves,...
So starting off with setting the a/f screws to see if that could be it is the way to start, then to the pilot jets....ect
 

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Actually i have a very similar problem. Last week I just got an 01' 660 and it rode fine during the test ride and for the whole day after, but after about the second day riding it first began to hesitate, sputter, and stalled once. So I rode it back to the house with it acting up the whole way and let it sit for a little while. I went back out to try it again it rode fine for the first couple minutes or so and then started hesitating again and dieing. Everyday since then i start it up and it idles for about 2 mins and dies. I changed the plug and it looked like there was a decent amount of soot. I'm guessing the carb needs to be adjusted but I pretty much have no idea how to do so. Anyone have any suggestions? I would really like to do it on my own instead of taking it to a dealer. (also, i forgot to mention the guy i bought it from lived in a more mountain filled area but I'm not sure how much higher the elevation was, if at all)
 
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