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2004 crf 250r ultimate remedy for top end?

By mtnmike,
in CRF250R & RX

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mtnmike

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So it is once again time for valves, valve seats, and such to be done on my 2004 crf 250r. I am looking for great advice on what the best remedy is for this darn adjusting valves and then needing new valves and seats cut ever so soon. I have stock piston. I have a stage II hot cams cam. I have a hot rods crank. What can I dooo??

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hdcp0

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Give yourself a new 2012 crf250r:)

j/k. The guy who does my engine work says to go with stainless values if you want extended life. I have them in my 08 but dont have enough time on it yet to determine if it is true. He also says that keeping a clean will prep'd air filter in your bike extends the life of your values no matter what kind.

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Keith72

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Make sure your airbox and the boot that goes to the carb has a perfect seal. There has been evidence that there are gaps in the sealer Honda uses at the factory. Seems to be fairly common and may contribute to sort valve life.

Steel intakes are not necessary and rob a little HP. Not a lot but some. If your are a rec rider steel is probably the way to go. If your a racer and want every advantage stick with the Ti intakes.

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mtnmike

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I so hear ya on a newer bike. But I am kinda stuck with this crap year of a bike. I have all kinds of money and wrk in it. So i gotta make do. So it sounds like stainless steel is a for sure. I have had my valve seats cut one time before and stock ti valves replaced. Will I need to recut them again, and/or can I replace them with better quality to help with longivity/reliablity? What brand of s.s. valves are best? Will I need to change springs??

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slammed83

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I too am in your boat.

I basically read every darn post on the net over the last week..

Seems the basic solution is cut seats and go to SS intakes. range from 300 to 550 it appears.

or replace seats with a different materail and continue useing Ti valves.

500-800 depending where u go and what all is included.

Seems to be 2 feilds of thought on these options ..

Some say SS has no loss in power , and even though they are heavier has no impact on valvetrain wear.

Others say that goin to the new seats is way to expensive and not required at all .

and some recomend nothing but OEM ..

there appears to be about 4 companies that offer a range of well advertized valve job options. some with new heads all sweetened up ready to go ..

they all offer what looks to be the same speech about why there head job is better then the rest and each in some way promotes a slighty different brand , or procedure for doing said job..

At the end of the day , choose a price point , and pick from one of the well known shops and get it fixed .. and get out riding !!

My personall belief is and this has no merrit as i have no expereince to back it up .

you could have a local machine shop / bike shop cut your intake seats. and you could fire in the SS (choose from top brands ) valves and be just fine..

that being said . I have choosen to send my head to RACERSER. not for any onther reason then , he seems legit , found some positive things about his work and i got tired of humming and hawing about where to send it and just fired it in the mail ..

Hope to get my head back sometime after christmass ,, maybe i can report back one day of my expereince ..

good luck

i ride 2004 crf250r.. ( unknown hrs on my head)

novice rider

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Keith72

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Do the springs with what ever brand you choose, most seam to go with KW. Defiantly get the seats cut.

BTW you may be able to get away with intakes only.

It is very important to have the exhaust valve guides checked for wear. If your intake valves are zeroed out there is a very good chance that the exhaust guides are out of spec and need replaced also.

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Charlie C

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I so hear ya on a newer bike. But I am kinda stuck with this crap year of a bike. I have all kinds of money and wrk in it. So i gotta make do. So it sounds like stainless steel is a for sure. I have had my valve seats cut one time before and stock ti valves replaced. Will I need to recut them again, and/or can I replace them with better quality to help with longivity/reliablity? What brand of s.s. valves are best? Will I need to change springs??

I would take a look at what size shim is currently in the intake valves. I've seen some heads where the seats were cut twice and there wasn't a thin enough shim to actually have any clearance for the valves. Depending on how much needs to be cut is going to determine whether or not they can be cut again. A reputable machine shop should be able to tell you if they can be cut again.

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redrooster65

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I would take a look at what size shim is currently in the intake valves. I've seen some heads where the seats were cut twice and there wasn't a thin enough shim to actually have any clearance for the valves. Depending on how much needs to be cut is going to determine whether or not they can be cut again. A reputable machine shop should be able to tell you if they can be cut again.

RHC/Tuff had valves to compensate for this.

My riding partner did OEM and then KW with no problems, pretty much standard shim size on the second valve job.

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Charlie C

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Have to also take into consideration that when the seats get too thin, they start to chip around the outside edges. I find the chiped seats imbeaded into the piston and head sometimes. The valve seat material can also destroy a cylinder if it finds it way into the right spot.

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lnjnickl

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SS valves kick ass. i put some tt in my bike and 3 months later i needed new valves. then i went to ss and i didnt even get my seats cut i only laped them in. i have been beating the hell out of m bike for over 50 hours and i havnt had to adjust them once. there was no noticeable change in power. i just love kicking one time and riding. SS are the way to go

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