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CRF450X Hard Start HELP


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Guy's I'm new to your site, and love all the info passed along. Someone PLEASE HELP. I have a new CRF450X and had bad problems with stalling / Lack of power. I took it back to the dealer, and he sold me a new jet, ( I'm not sure what size ?? 64?? ), he also sold me a smog pump block off kit. He then instructed me to adjust the Fuel Air needle to the 2nd notch/ groove from the top. Totally awsome!!!! But........ Heres the problem I'm having, This Beast still is really hard to start. I pull the choke out, crank the throttle 3-4 times and hit the starter. Some times it just wont fire......If I've had it running in the last 48 Hrs....It will fire up, if it has been sitting for longer than a few days, Damn thing just doesnt want to fire up. Please Help...... I would love to spend alot more time on this beast, but as for now, it sits in the garage taunting me everytime at look at it. Thanks in Advance,

'DOG

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What type of jet is it , pilot? main? try not cranking throttle, I have a 05 and if I touch the throttle it won't start, sometimes the choke is too much. Also charge your battery, if battery is a little low it's a tough start.

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Main Jet, Batt wont hold a charge very much, even though I've had it hooked up to one of those Honda automatic chargers. In the past, if I tried starting it with out giving it any gas, it'll just crank away without so much as a cough. Could the fact that I havent " Uncorked" the air box or done the Exhaust Baffle Mod's have any impact??? Great "Stickys" on this web site that will help greatly with these. Can wait to get home and try these 2 Tactics. What Do You Think???? Too little Air ???? Too Much Exhaust Restriction. Plug's not fouled. Any input is a big help, Thanks All,

' DOG

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I bet you are experiencing a rich condition. If you jetted without modding anything else unless of course you jetted to accomodate that fact that the air box is still closed and the exhuast is stock. By the way how many hours do you have on the bike? Is your air filter clean? and cleaned on a reg. basis(every ride) Do you run S%^t gas? Have you tried cleaning your carb. Has it been like this only since you jetted? Did you buy new or used?

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O.K. , Here's the low down, Bought the bike new....... Bike had NO Bottom end, kept stalling out going up even moderate hills / inclines. I Went back to the dealer and asked " what the heck, I thought these things could muscle up anything?" He informed me that they are very lean out of the box, and with the addition of the pump, they just dont breath right. He sold me a new main jet, ( Larger, but I cant remember the exact size ), he then instructed me to adjust the needle into the 2nd slot from the top. All of this has been done, He also instructed me to do the exhaust mod's, which I didnt do . I Couldnt get the darn baffle out like another TT member. But, with the help of the " Sticky" thread addressing this, I think it'll be a piece of cake. I'll try this tonight along with opening up the aircleaner box, as also stated on your site. I Believe the Main Jet size was 164 ( I could be wrong ). The bike has always been alittle tough to start, but once warmed up has started up fine. Gas might be an issue, I'll drain and re-fill with Premium. Just wondering if the Air Cleaner/ Exhaust Mod's might make a differance??? ??

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If it is a 165 main then you are running too rich for your lack of mods. To mod the baffle do what I did. I removed the whole spark arrestor and drilled a small hole in the tip and punched the baffle assembly out. Much easier than trying to pull it. Just seal up the hole with a little JBweld. Mine worked like a charm and as long as you do a neat job on the JBweld it looks just like a regular weld and not too shabby at all.HTH

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'Dog, drain your tank and carb and refill with Premium (91 octane) at least. Higher octane will be even better for your engine (if you can find it).

IMO, if you do one mod, such as rejetting, you have to do the other mods, too. The bike won't run right (if at all) without all 3 mods done at the same time, the airbox, rejetting, and removing the exhaust baffle (or doing what I did, which is replace the exhaust with a FMF TiPowercore 4). If you rejet without opening the airbox, you've got too much fuel for the air that can get into the engine. If you open the airbox without rejetting, you've got too much air for the fuel that can get into the engine. If the baffle is still in the muffler, the burned fuel/air can't get out of the engine, so it doesn't run right (way too much back pressure).

So, to answer your question, Yes, the airbox, jetting, and exhaust mods will make a difference. When it's finally dialed in, you're gonna love that bike.

Check my garage for mods I did to my 450X (it's an 05, so I didn't have to worry about a smog pump).

Good luck!!

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SaltyDog,

I'll have time Wed after work if you want to come over and mod your air box and the exhaust, then we'll see how it runs and figure out if you need to get the JD jet kit (worth it's weight in gold) or if what you're running will work.

Check your PMs for my phone number.

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Last year I bought a new 06 CRF450X and experienced the same frustrations. After much research on this site here is what I did to my bike and now it runs perfect from sea level to 3000 feet. It was worth the money and time.

1> Installed the JD Jetting Kit

2> Installed Red Needle with clip at 3rd position

3> New #170 Main Jet

4> New #48 Pilot Jet

5> Boyesen Accelerator Pump

6> Zip-Ty Fuel screw out 1 1/8 turn

7> Installed fat rubber O-Ring on throttle linkage

8> Checked throttle linkage gap and set it to 2.5mm

9> Opened top of airbox (cut open along ridge outline)

10> Opened sides of airbox (cut open same size as number plate slots)

11> Replaced stock air filter with TwinAir filter and removed screen.

12> Installed E2 WB muffler/spark arrestor

13> Pulled off the fat rubber hose connecting to the emissions device

(Cal only) and duc-taped the input and put the rubber hose back on.

No more deceleration backfire popping

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I got a stock '05 at sea level with cold temp about 10-15 celcius...

The only thing I did is to uncrew the fuel screw at 2 turn.

It's a little bite hard to start: with wacking the trottle it start and stall 2 or 3 times before it keep a relative idle on choke. With cranking the idle screw, it do it better. And after 2-3 minute of slow riding, when the bike is hot, it rip dirt like hell !

PS: I know I sould do all the uncorking thing, but U know... I just have money for gas, and I'll get a new tire before anything.

Maybe the fuel is not only the trouble... check for the fire !

Look at the coil if the little black wire is plug. Sometime when you take off the fuel tank, it unplug from the coil cause the petcock grab it when you lift the tank.

Look at the sparkplug too !

GoodLuck !

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I got a stock '05 at sea level with cold temp about 10-15 celcius...

The only thing I did is to uncrew the fuel screw at 2 turn.

It's a little bite hard to start: with wacking the trottle it start and stall 2 or 3 times before it keep a relative idle on choke. With cranking the idle screw, it do it better. And after 2-3 minute of slow riding, when the bike is hot, it rip dirt like hell !

PS: I know I sould do all the uncorking thing, but U know... I just have money for gas, and I'll get a new tire before anything.

Maybe the fuel is not only the trouble... check for the fire !

Look at the coil if the little black wire is plug. Sometime when you take off the fuel tank, it unplug from the coil cause the petcock grab it when you lift the tank.

Look at the sparkplug too !

GoodLuck !

I would do all the uncorking anyway if I were you. If you do just the airbox(free), muffler (free), and jetting it is cheap and well worth it. I spent about 30 bucks CDN to do mine. Just order the parts from Kehin(through your Honda dealer) instead of from Honda.WAY cheaper.Like 1/4 the price.

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