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03 cam mode ant tips

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I just bought an 01' WR 250f. Previous owner put the yz cam w/ adj gears! Bike rips but will NOT start when it is cold. The Wr's are notorious for starting hard and I heard the cam just makes it even harder to start. Im thinking of changing the cams back to stock wr so the :cry: thing will start!

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I just bought an 01' WR 250f. Previous owner put the yz cam w/ adj gears! Bike rips but will NOT start when it is cold. The Wr's are notorious for starting hard and I heard the cam just makes it even harder to start. Im thinking of changing the cams back to stock wr so the :cry: thing will start!

there are no OEM YZF cams with adjustable gears, so it must be an aftermarket cam set.

that said... the cams, if properly installed, have little to no bearing on how hard the bike is to start. on the other hand, valve clearances, jetting, spark plug condition, etc do have a major part to play when starting.

WRF's are no harder or easier to start than YZF's. i have an '01 WRF, my brother has an '01 YZF; there really is no difference. the '03 exhaust cams do of course uncomplicate the starting drill. if you change back to OEM WRF cams and WRF timing you will lose power across the rpm range.

look to your adjusting fuel screw to help starting. there is tons of info in the 250F FAQ related to jetting and adjusting your valve clearances. if i had to identify the two biggest contributors to hard starting, i'd say (1) valve clearances and (2) fuel screw setting. it would not surprise me whatsoever that your '01 WRF is due for valve adjustment.

see

http://thumperfaq.com/valves.htm

jim aka the wrooster

'01 wr250f w/ '03 YZF auto-decompression release cam set to YZF timing.

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any tips on putting 03 yz cam in my 02 wr 250 any tips would be appreciated

250F FAQ has all the info you need:

from

http://thumperfaq.com/sitemap.htm

grok

http://thumperfaq.com/autodecomp.htm

and also see

http://thumperfaq.com/yz_timing.htm

and

http://thumperfaq.com/cam_timing.htm

and if you screw up

http://thumperfaq.com/cam_timing.htm#Scratch

jim aka the wrooster

'01 wr250f

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thanks guys i guess i will tackle the job tonight,by the way north county yamaha in california sold me the cam for 114.86 a tt comp plug for19.68 and 8.00 shipping

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Yamaha,are you listening? Can we have digital fuel injection and end this jetting nonsense :cry:

do you mind if they add a heavy battery, a charging circuit, high pressure fuel pump and lines, and another expensive black box to your bike? moreover, in order to make any adjustments you have to take your bike to the dealer so they can hook it up to their hyper-expensive re-jetting computer?

jim aka the wrooster

'01 wr250f

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do you mind if they add a heavy battery, a charging circuit, high pressure fuel pump and lines, and another expensive black box to your bike? moreover, in order to make any adjustments you have to take your bike to the dealer so they can hook it up to their hyper-expensive re-jetting computer?

jim aka the wrooster

'01 wr250f

Actually,the charging system and battery on the WR will suffice quite nicely! A small 35PSI electric fuel pump in the tank will work as well.CPU can be incorperated in the ignition black box with a waterproof RS232 interface connector.A palm pilot with software will handle any jetting issues you will ever see.How about mapping courses on the cpu(YZF) and adjust jetting corner by corner!It will happen sooner or later.The carb is crude and somewhat fixed in its operation-works extremely well but is at its zenith of development. :cry:

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I changed my mind.Have an infrared led behind a rubber cover on the black box for an optical interface.

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Thanks for the info partner!! I already installed a tip tye fuel screw and it didnt seem to help the starting issue. I have also thought about ordering the JD jetting kit. I think it might help more than anything just b-c I do most my riding at altitude. (4,000-7,500Ft.) If that doesn't work the next stop is the SHOP and checking those valve clearences.

Thanks again

Aaron

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you were right about the valve clearnces...........took it into the shop and they were indeed due for adjustments. The snow is coming down here in durango and its raining in the dess so I cant ride. :):)

Thanks for the FAQ

adub

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Question for the guys with the 03-up bikes or the 01-02 with the 03 cam swap done: Is the bike physically easier to kick over? I have knee injuries galore so anything to help would make it less painful to ride!!

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Is the bike physically easier to kick over?

very much so. it's like kicking a 125cc two stroke.

jim aka the wrooster

'01 wr250f

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that said... the cams, if properly installed, have little to no bearing on how hard the bike is to start. on the other hand, valve clearances, jetting, spark plug condition, etc do have a major part to play when starting.

Just for the record.

the hotcams cam has enough adjustment in it to retard the cam to the point where it is open far too late in the intake stroke. With that late of timing the piston can actually push a majority of the charge right back out the intake and you end up with zilch to ignite when starting it.

It took me a lot of pilot jets and starter jets to find it. And I'll be danged if it wanst the 450 guys that discovered it first too. :)

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very much so. it's like kicking a 125cc two stroke.

jim aka the wrooster

'01 wr250f

Wow, in that case I'm ordering it tommorrow!! :)

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Please HELP!!!!!! My 01' wr is still not starting when it is cold and i have had trouble on the trail too. Valve clearences were checked a couple weeks ago and I installed a fuel screw. Free mods are done. Im at a complete loss of what to do about the starting issue!! JD jetting kit? I do most of my riding at 4,000-12,000 feet in the summer. Please help! :D:D:p:):)

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Im not sure........Im going to take the carb apart and find out what all the jets are. Thanks for the reply. I will let you know soon.

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I actually took the whole carb completley apart, cleaned and blew out all the jets with compressed air!! There was tons of fine Utah dust, tarnish and what not in the carb. Anyways, I went ridiing after that and the damn thing acutally fired.... I think I figured out the trick to starting it!! ie. (a little throttle) Everyone told me that was the last thing I wanted to do was flood it with gas. Now I know it actually needs a little throttle blip upon kicking it.

I think the bike will still run rich though especially in the high forest.

Leak jet-60 *Standard

Pilot jet-45 *42 is standard

Main Jet-152

Thanks

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