set up tips for 2004 yz 250

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#1
I just changed from a 1999 cr 250 to a 2004 yz 250. Are there any "yamaquirks" I should know about. I was well satisfied with the Honda I just like change. My yz has already fouled two plugs, then I leaned her out and that took care of that. Ive already disassembled the bike and greased everything. Ive put a skid plate, frame guards, radiator braces, 11 oz flywheel weight and scotts stering stabilizer. Ive only made two trips around the yard on the bike. Each time I foulded a plug. Anyway I plan on breaking the bike in proper fashion soon on the trail....Any experiences youve had with the 04 yz 250 i would be glad to hear them good or bad. Ive also been hearing that HP2 2 stroke oil is notorious for fouling plugs. Ive had the maxima and silcolene oil recommended to me as a better oil. Any thoughts on this would also be appreciated.
 

Studboy

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#2
As for the "yamaquirks" if you are trail riding you will soon yearn for a larger and softer seat!!! Yamaha doesn't waste any seat foam on their MX bikes.

I'm tempted to duct tape a pillow to my seat whenever I trail ride. :debil:

As to the oil, none of those oils will foul your plugs if you are jetted correctly.
I've been running Mobil 1 in mine and I like it, but HP2 and Silkolene are both excellent products as well.
 

whyzee

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#3
Red, My 04 fouled 3 plugs Sunday, I have not had a chance to diagnose the problem yet but it was suggested that my main could have dropped out. I plan on getting to the root of the problem this weekend.
My thoughts are:
bad gas,
poor jetting,
wrong oil
The bike ran fantastic last month in 70* weather, this 30* stuff is hell, I would have expected it to run a little lean, but it reacted as if it were too rich.
 

James

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#4
Dave,

Does it sputter when you get hard on the gas and make a lot of smoke?

I rode 2 practices and 2 heats at Parker Valley without a main jet, these were the main symptoms. When I got it back in for the main events, I was surprised at how easy it became to jump over Ivan in the double double section.

I use HP2 and have never fouled a plug, not even that day without the main jet, so I wouldn't think it would be notorious for fouling. Sounds like something else.
 
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#5
Ive already went one clip leaner on the needle. This weekend i plan on going one jet size leaner on the pilot and mixing the HP2 at 40:1 instead of the recommended 32:1. I hope it cures the problem. Those $5 dollar plugs get exspensive..You know it may be easier to adjust valves (4 stroke joke haha).
 
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#6
Check the float level before going any further. Several of us have had this problem. Stock jetting is pretty close.

Guy

03 YZ250
 
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#7
For what its worth. I have about 150 miles on my 04 YZ250 and have yet to foul a plug. I have been running Maxima Castor 927 mixxed 32:1 with stock jetting, altitude around 1500ft ASL and temps in the 50s. All of this has been tight woods trail riding. Bike runs like a top.
 

frankrock363

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#8
I have been riding an 03 for a year now and have never fouled a plug.I ended up going one jet size bigger on the pilot and main to help control the ping these bikes realy want race gas.Unfortunatly I am to cheap for that.I run motul 800 at 36 to 1 and swear by it.It's possible if your back yard is not to big you realy have not had the chance to blow it out.By the way the colder it is out the more likely chance you will have of fouling a plug even though the cold will lean it out,it just takes that much longer for the engine to warm up.
 
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#10
Frank is right, unless your yard is a few acres or so, just putting around the perimeter of your house you are going to foul plugs like crazy.
 
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#11
'99 CR vs. '04 YZ

Redrider said:
I just changed from a 1999 cr 250 to a 2004 yz 250. Are there any "yamaquirks" I should know about. I was well satisfied with the Honda I just like change. My yz has already fouled two plugs, then I leaned her out and that took care of that. Ive already disassembled the bike and greased everything. Ive put a skid plate, frame guards, radiator braces, 11 oz flywheel weight and scotts stering stabilizer. Ive only made two trips around the yard on the bike. Each time I foulded a plug. Anyway I plan on breaking the bike in proper fashion soon on the trail....Any experiences youve had with the 04 yz 250 i would be glad to hear them good or bad. Ive also been hearing that HP2 2 stroke oil is notorious for fouling plugs. Ive had the maxima and silcolene oil recommended to me as a better oil. Any thoughts on this would also be appreciated.

Have you been able to clear up your jetting? I am interested to hear how you think the YZ compares to the CR. I am currently racing a 2001 CR250 in Harescrables. I am considering getting a YZ250 as my next bike. Interested in your thoughts about the YZ. Thank you.
 
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#12
BillyJ,
To be honest I still have not had the chance to really ride the yz in the woods yet. As far as the cr goes.....I really love the bike in the woods, but after riding the 04 cr 250 i was really disappointed with the power down low on the bike which is where i stay trailriding. I rode a yz 250 (stock) for a short while a friend of mine owns and for the life of me this bike had more torque stock than even my 99 cr 250. THis is really what sold me on the bike. The power down low on the yz is almost "4 stroke" like...I will let you know when I really get to ride the bike on a real 50 mile ride. Thats when the truth will really come out. :laugh:
Later
 

Ronson

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#13
2004 Yz 250

Redrider- How are you liking your 2004 YZ. Did you notice much of a difference between your 99 YZ and the 2004?
 
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#14
BillyJ said:
I am interested to hear how you think the YZ compares to the CR. I am currently racing a 2001 CR250 in Harescrables. I am considering getting a YZ250 as my next bike. Interested in your thoughts about the YZ. Thank you.
I just went from a '01 CR250 to an '02 YZ250 and I like the Yamaha much better. The motor has a alot more low end. I re-valved the suspension with Race-Tech for woods and it is sweet. I think the Yamaha handles just as good, if not better than my CR. I am very pleased with the bike.
 
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#15
CHECK the float bowl level; that's the problem with these bikes fouling. Mine was way off and after readjusting I can putz around with my son on his 03-xr-50 without any fouling. The bike will idle with no problem's as well. Start's up every time on second kick. My fuel/oil ratio using Amsoil Pro Series 2000 is 40-1 with Sunoco 94 premium. This bike rock's.ONLY other bike I'd give it up for is the 04-CRF-450. Wifes cousin bought a dealership and now I can test different bikes and that's how I can do my comparison's.