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Hello All,

I review this forum from time to time when I have a problem I cannot figure out - Thanks to all who contribute. However, this is the first time I have asked a question. I realize that the answer could likely be found somewhere in previous posts, but I could not find.

I have a stock 2001 raptor that I feel is running hotter than it should. The headers glow orange for about the first 4-6 inches out of the head (pretty much the whole curve + some) - Clearly this is only noticeable at night. The fan seems to come on quickly and runs often. I have also had to put the carbs back on the boots a few times over the last year. The bike experiences slight backfires at lower rpms (guessing around the 2000-3000 range), but they disappear for the most part once the bike warms up (gets HOT). The bike does not backfire at all out side of this low rpm range – it actually runs very smooth... Also, it is more like a hiccup or small cough rather than a massive set of backfires.

I have heard people say these things "run hot," but I am not sure I believe that a stock bike is supposed to glow the headers under rather meek riding conditions. It is my understanding that the fan kicks on somewhere around the low 220's farenheit. Since the temp is being read after the coolant leaves the head, you have to believe if the fan is kicking on, that the motor is running hotter than that. Since mine seems to kick on after just a few minutes of puttering around, I can’t help but think something is out of tune. I am not a mechanic, but did study engineering in college and am inclined to think it best if a motor stays around 200 degrees farenheit or slightly under if possible. I struggle to think that my bike is supposed to run as hot as it does. Maybe it is just running a little lean (I have never touched the carbs) or maybe it has carbon buildup (which I doubt)......or maybe.....

The last time I adjusted the valves, the plug looked good, but I put a new one in anyway since I had the plastic and tank off. The valves seem to stay in adjustment and the motor runs without unusual noise when you listen closely. The bike has good power at all ends of the curve - with exception of the slight backfiring/cutting out that occurs at low rpm strolling – but if you just open it up from the get go, you never experience this coughing/hiccup stage – it only seems to last for 1000 rpms or so in range. I would appreciate any help in diagnosing/fixing the problem.

Also, I have never had the spark arrestor out of the pipe. I tried to take it out a few times a year or two back and again recently, but cannot seem to get it out!! Part of me wonders if there isn't some level of carbon deposits on the screen, but I do not think I have ever seen one that has had much buildup - even after years of riding. Probably a moot point, but I would like to remove and inspect. Of other importance – I live in TX, so the bike has not experienced harsh weather and corrosion causing salts. The bike has always been garage kept. Also the dummy temp light has never come on – does anyone know at what temp this happens? If nothing else, I will know that even though I think my bike is running too hot…..at lest it is under __ degrees!

Thanks,

Eric
 

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i would say youre lean at the bottom(Pilot), if its stock bump it up to 25 or play with the mixture screws. It is normal for pipes to glow close to the header @ night.
 

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660RaptorR said:
i would say youre lean at the bottom(Pilot), if its stock bump it up to 25 or play with the mixture screws. It is normal for pipes to glow close to the header @ night.
my pipes glow in the day time at idle and i mean really glow :eek: but its been ported and polished and bored to 100.5mm with stock jets it needs to be rebiult now anyways :thumbsup:
 

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You're running way too warm. Is there water in your oil or are you losing/using/burning coolant? I'm assuming since your bike is stock the jetting is as well. Even at sea level the size of the jets shouldn't be causing the problems you're having especially with an oem intact airbox, but you should adjust your fuel screws out to increase flow and it's not a bad idea to pick up a set of 25 pilots just in case. It's not a bad idea to clean the carbs and check the fidelity of the intake/carb boots to make sure extra air isn't finding it's way in.
 

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Discussion Starter #5
There does not appear to be water in the oil nor does the bike appear to be burning/losing any coolant. I inspected the carb boots a few months ago and they seemed OK - to the extent of my inspection. I will try to pull the carbs in the next week or so to clean and inspect. I have never removed them from the bike, so I may have more questions to come if I run into any trouble and cannot get back on track by using my manual or reviewing previous posts.

The bike is indeed 100% stock - carbs and jets included as well as the air box What is the std setting for the mixture screws for a stock 01' Raptor? Is it 3 full turns out from seated? I'm surprised my service manual does not seem to house this type of information.....

I will post my findings and results once complete.
 

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Discussion Starter #6
I pulled the carbs off and tore them apart - all the internals were in good order and didn't even appear to need cleaning. It was unfortunate in that one of the pilot screws (air mixture screws) was just about welded tight! Once stripped, I tried to get it out with a reverse drill bit, but no such luck. I ended up drilling thru the screw and then re-tapping it. I had to borrow a tap since I didn't have one that size. All ended up well. I picked up my new pilot screw today and put everything back together. I ended up turning the mixture screws 3 full turns out from seated and all seems better. Hard to say if it is still "running hot" b/c it was in the 60's all day today. However, if I had to guess, I would say it is running cooler. The fan didn’t cut on even after a small ride and idling for about 5-10 minutes.

I was also finally able to get my spark arrestor out of the tail pipe. It was pretty clean given the fact it had never been out. It was just really "welded/rusted" in there.

All seems good with the Raptor now, so maybe it was just that the pilot screws were too tight. If I had to guess they were about 2 full turns out from seated before I started disassembling. The small range of back firing also seems to have disappeared. All in all, I'd say my Rappy is Happy :thumbsup:.

Thanks for the input.

Eric
 

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I actually wrapped mine with header wrap. Keeps my legs cool and and prohibits even the smallest leaks. What do you think?
 

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Thats stuff clean easily? Mud and crap come off without screwing up the wrap when washing. just wondering? Looks prospective.
 

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So far it's been really easy. Have had no trouble with it what so ever. It get alot of mud and dirt and washes right off. I can actually grab the header while its running with no probs. I ride every weekend and was always trying to keep the oxidation off the header. I live in Miami and theres water and mud everywhere. I just wanted it to be easy to maintain and also look different.
 

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Buckeye :mad:
 
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