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Questions on Carb/Please bare with me..

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So this is my first dirt bike in 15 years. 05 RMZ450 and it runs 110%. Has a weisco piston and crank new valves new everything and the guy I got it from is the main mechanic at our local bike dealer so its rock solid. I have a question about the carb because i have never owned a 4 stroke race bike. So I live at sea level, the guy said he tuned the fuel air and it has an after market one you can just turn which is nice, so that he can ride at sea level and around 1000 ft. The bike starts up first kick when cold with choke, if stalled first kick starts right up, no stalling at all when getting on the throttle, WOT is freaking insane, no back fire, idles great but when warm just for the hell of it I was curious so I put it on full choke, it rose the rpms a bit and the bike still ran but did not kill it, it did sput a little bit but it kept running. Anyways I just wanna make sure im not too lean-would rather be too rich than too lean because I love this bike and dont want to mess it up. I have not messed with anything and he said the fuel air screw is 2.5 turns out. Thank you.

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I figured when choke is on it gives it more fuel, so the idle climbs when bike is warm and i put it on full choke and the bike is burning the extra fuel from full choke but when i take off and open it up it doesnt run as good with the choke off obviously..Just wanna make sure im not lean and blow up this brand new rebuilt awesome super powerful engine..sorry please bare with me im new to this its been a long time. Thanks guys.

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Use the choke to start the bike... no other time! It sounds like it is jetted well. Leave it alone. You got a proper response when you pulled the choke. 

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The idle went higher because you introduced more fuel to the combustion chamber. It sounds all good to me man.
The idle will rise if you pull the hot start lever too because it's getting more air (that will cause it to be lean) but it may be necessary to use that once the bike is hot or you will be kicking for a long time. With these bikes, you will know if you're running lean because it will backfire on deceleration. Your Plug condition will also tell you anything you need to know about tuning.

The goal is for the plug to be a tan/light brown color. Not black or white. Black is rich and white is lean.

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cool ill leave it at that...hey guys..I have a BAD ASS 05 RMZ450!!! I don't make much money we usually live check to check I am just so damn happy I have an awesom race bike..even though I am not racing it I have been riding some pretty tight trails but I have already got used to the 4 speed on these trails in about 6 hours of riding. Came right back to me. Used to race when I was a kid but my paps worked on the bike. If I were to go up a tooth on the rear sprocket how much of a difference would there be when taking off in first/riding tight trails? WOO HOO I AM SO STOKED!!!

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Oh hey the air filter is a little dirty and its a no toil filter. Alls I have is a k&n cleaning kit, the spray cleaner and oil, can i clean it and re oil it with the k&n products or should I just get a new one soon...also..another cool thing about this bike..the guy wired in an hour meter which is awesome..the bike is awesome as hell did I mention that?? Ha ha sorry just excited.

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Oh hey the air filter is a little dirty and its a no toil filter. Alls I have is a k&n cleaning kit, the spray cleaner and oil, can i clean it and re oil it with the k&n products or should I just get a new one soon...also..another cool thing about this bike..the guy wired in an hour meter which is awesome..the bike is awesome as hell did I mention that?? Ha ha sorry just excited.


The K&N recharge kits are meant for paper/fabric air filter elements, not foam. I would not use it. No toil sells their own kit, but I would just replace it with a ready to go one from no toil. But I strongly recommend the UNI 2 stage filters. They work amazing and last forever just be sure to use their cleaning kit. Whatever you do! Make sure that filter is completely 100% dry before you apply the air filter oil.
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So would you guys say this is a good bike? About 10 hours on a Weisco piston and crank and all the bearings and new valves and valve springs and cams and stuff. Everything was rebuilt to factory spec but with better internals..I wonder how many hours the motor will last if I change the oil every 3-6 hours because I just trail ride and jump water bars, oh yestarday ya I got like 10 feet air and cleared about 45 feet off a water bar in second gear, it was awesome. See I raced crotch rockets for a little bit and am very experieced riding them on the street, I had an 06 R1. Also where is the "strainer" located for the oil change and how often should I pull it?

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Okay thank you so much. Man it feels good to have a nice bike. If my wife would let me I would put it in the living room so I can just stare at it while Im on the couch haha.

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cool ill leave it at that...hey guys..I have a BAD ASS 05 RMZ450!!! I don't make much money we usually live check to check I am just so damn happy I have an awesom race bike..even though I am not racing it I have been riding some pretty tight trails but I have already got used to the 4 speed on these trails in about 6 hours of riding. Came right back to me. Used to race when I was a kid but my paps worked on the bike. If I were to go up a tooth on the rear sprocket how much of a difference would there be when taking off in first/riding tight trails? WOO HOO I AM SO STOKED!!!


I run a 13 front 51 rear and I can pull the front wheel up in 4th gear. In my opinion these bikes don't really have a viscous bottom end, but the bottom end of the midrange powerband is crazy.

Be careful about overheating your bike on the trials. These bikes don't particularly like slow and technical because they were designed for purely motocross where airflow is constant and strong through the radiators. I would advise upgrading to a higher pressure radiator cap if the previous owner didn't do so already. If your bike gets too hot for the current cap, it will boil over and you will be forced to push your bike back to the truck or you risk causing serious damage.

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So would you guys say this is a good bike? About 10 hours on a Weisco piston and crank and all the bearings and new valves and valve springs and cams and stuff. Everything was rebuilt to factory spec but with better internals..I wonder how many hours the motor will last if I change the oil every 3-6 hours because I just trail ride and jump water bars, oh yestarday ya I got like 10 feet air and cleared about 45 feet off a water bar in second gear, it was awesome. See I raced crotch rockets for a little bit and am very experieced riding them on the street, I had an 06 R1. Also where is the "strainer" located for the oil change and how often should I pull it?


I personally love these bikes, just because I know the RMZ's inside and out. Been working on them for 10+ years now and I've owned about a dozen. First thing I would do is download a manual for your bike. I know for a fact there is a couple free ones online, but you have to look. You could also buy a downloadable one for about 3 bucks if you don't have time to look. I would post the links but ThumperTalk is strongly against sharing manuals.

But to answer your question, I only pull the strainers if I notice anything abnormal in my oil. Like big flakes or big particles. The manual will tell you where it is and how to pull it.

Also try the search bar at the top of the screen. Most if not all these questions have been answered and tons more you haven't asked, I don't mind answering them, it will just save you some time.

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Why thank you very much. On those trails I'm usually going at least 25 to 30 mph hope that's enough air flow. 

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