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yz250f 2009 Athena 290 Questions

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Hi guys, i'm opening this thread for the future because today i got 2009 yz250f with athena 290 kit. I will be only in the woods, probably no MX at all. So i have a lot of questions and i'll appreciate every advice you give me. I've ridden several 250f and for my type of riding(bottom to mid rpms) the power of the Athena is more than spectacular to me. Really really like it. Overall the bike is well maintained, 80% of the parts are brand new.

So my 1th question for today - he told me that the oil reservoir is removed. On oil change - 650ml

oil change + oil filter - 800ml.

Of course i asked why he removed it and he answered that it was extra weight and there was not good oil "flow" around the engine. I'll be happy to hear some thoughts about it. Thanks!

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i would never remove my oil tank,i highly doubt that the yammie engineers dont know a little bit about oil flow.why would you want to run less oil than the stock amount,which in my book is one of the reasons these motors are so reliable.i do like the 290 kit,they run awesome,not so much for moto,but for enduro or trails,they work great.i have 4 of these machines,a 08,09,and 2 2010's.imo you will be hard pressed to find a better machine,that can be made to do whatever you want it to do.peace and wheelies.

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i think the same way. They put it for some reason. I think the weight loss is not that significant. Is it that simple to remove it and just bolt the holes or they put some restricting parts. I am asking because i can find used oil tank and put it there. Can i mess up something by putting it back in? Is it just for 09 or i can get it also from 07 and 08? Thanks!

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most of the yz250f race motors are dry sump, it is less weight and better flow but much more maintenance

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Quite a few people instal the wet sump kit so it's not that uncommon. There are pros and cons to it. Biggest con is there is less oil in the system to lubricate so you need to change the oil twice as much

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I found a few threads. Helpful information and i am buying an oil tank. So now - can i get from 07 and 08 for my 09? or they are different. I think that i will need the stock parts that are replaced probably. I will look into that also. If someone knows exactly which parts are removed it will be good. Thanks!

Edited by nk_dimitrov

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You have to take off the side cover and change out the oil pump plate.

http://www.dubachracing.com/cart/index.php?main_page=product_info&cPath=4_31&products_id=1787

If you look at the picture at Dr.D's website you can see the little aluminum plate that is put in place. You have to remove this and replace it with a stock plate. Honestly I would leave the oil tank out of the bike. No other manufacture uses them and they just add extra weight. I personally like it becasue now the crank is constantly sitting in oil where as with the tank on it is not submerged in oil. But that is just my .02

O yea and removing the whole system does save 3 lbs of weight and since I race MX every little bit helps.

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Thanks for the help. I ride enduro at the weekend so we go around 60-70km hard steep rocky climbs, woods, etc. I read that even the wet sump manufacturers advice oil change every 1-1 1/2h. If i am a recer - why not. For me it's just not possible to put new oil in that interval( i will just feel like smashing my motor every time i hit the throttle in the woods on the way back...). I am getting Hourmeter so regular oil change but 1h is too soon for enduro. Thanks!

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650ml has to work a whole lot harder to do the job that was intended to be done by 1100ml.

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+1 almost twice as hard...

Getting ready for tight, steep rocky hill climbs/trail rides so now it's 13/48 sprockets. I've had the bike for 2 days now. It's too cold for me to go test it in the woods but from the time spent on the bike on straight roads i feel like a lot of shifting, getting to 4-5 very easily at low speed. I read that most of the guys like 13/50 on the 250f but the athena really gives a lot of bottom. It easily goes wheelie in 1-2-3 gear w/o any clutch... I think that more than 48 will be too much. The current sprockets are in bad shape and i don't feel like going in the woods next season w/o new ones. I guess 13/48 to 13/50 on stock 250f motor can be(in some way) similar to 250-290 bottom effect. Correct me if i am wrong. Cheers!

Edited by nk_dimitrov

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To bad you are so far away. I would give you the plumbing for the tank as I have every thing except the tank itself. I dont really think it would be an issue to leave it the way it is just make sure you do your oil changes frequently. Good luck. :smirk:

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+1 almost twice as hard...

Getting ready for tight, steep rocky hill climbs/trail rides so now it's 13/48 sprockets. I've had the bike for 2 days now. It's too cold for me to go test it in the woods but from the time spent on the bike on straight roads i feel like a lot of shifting, getting to 4-5 very easily at low speed. I read that most of the guys like 13/50 on the 250f but the athena really gives a lot of bottom. It easily goes wheelie in 1-2-3 gear w/o any clutch... I think that more than 48 will be too much. The current sprockets are in bad shape and i don't feel like going in the woods next season w/o new ones. I guess 13/48 to 13/50 on stock 250f motor can be(in some way) similar to 250-290 bottom effect. Correct me if i am wrong. Cheers!

Around here at 600' ASL and 200lb and under rider, with spot on jetting for a 290, the optimum gearing is 13/46 or 13/47.

Add teeth for altitude and weight would be my suggestion.

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So now - can i get from 07 and 08 for my 09? or they are different.

07-09 YZ250F oil tanks are the same part number. I just checked last week since I stripped out the threads of the vent bolt on top of the tank.

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Checked my valves. My intake are 0.14mm(all of the 3). One exhaust is 0.17 and the other is 0.19mm. By the shim chart i am in spec. But i am splitting the engine, so it's quite easy to change, check everything. So what do you think? Should i get smaller(thinner) shim for the 0.17 to make it closer to the upper limit or to let it that way. I need to check the shim size in first place ofcourse.

Havent repaired 4 stroke so taking off 5 valves etc is something i would skip that time. Should i disassemble the head and inspect the valves, seats, springs, seals etc... I havent ridden the bike for more than 10min but it did start from the 1th kick when hot. The PO started it cold from the 4-5 as far as i remember(he said that the bike hadnt beed started for a week or so...). Also the manual suggests pooring in solvent to see if it's goind to leak from somewhere. Is that good enough test for the valves?

The crankcase is cracked so i am ordering new one. Everything is going to be checked and measured.

Any tips and thoughts will be appreciated. Cheers!

Edited by nk_dimitrov

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07-09 YZ250F oil tanks are the same part number. I just checked last week since I stripped out the threads of the vent bolt on top of the tank.

And you bought a new oil tank because of the stripped threads!!!

Why?

Edited by 2grimjim

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Another question - the dust seals(upper ones) on the rear shock how should be placed? I looked and decided to put them with the numbers facing me(like the bearings on the linkage). Is that the correct way? P.S.about my previous post - i got it. Cheers!

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