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First Rebuild Question

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So I've got an 05 CRF250 that i have put about 12-14 hours on it. I did my first valve job at about 10-11 hours because it would not start. The exhaust were dead on but the intake were pretty far off (almost metal to metal). I set the valves so that I'd be on the loose end of the spectrum (.006 inches) to give me a little time before the next valve adj. Only two rides later (approx. 1 1/2-2 1/2 hours) I went to start the bike after a day at the track and again it would not start. So I went in, and the intake are almost metal to metal again. I'm pretty angry with the bike considering it's so new but I do realize I ride the hell out of it and rev it pretty hard and I have been reading about the valve maintenance on the Hondas.

I would do another valve adjustment but I hear that once they start going like this it's best to change them. So I'm going to order up some new valves and am wondering if I should maybe put some new rings on while i'm in there? Anything else you recommend doing? This is my first race four stroke and I sort of miss the reliability and simplicity of my RM 125's already.

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Let me get this straight... you bought a used 05 and you've put 10-12 hours on it right???

If you're asking me, I'd do the works while I was in there.

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he hasn't rebuilt it yet. he is asking what he should do when he does rebuild it :D but you do bring up a good point, get your seats cut. rings and piston replaced, inspect the bottom end. throw it back together and :) when i got my 04 i had the same problem. once you rebuild it its pretty simple. my valves haven't moved in 40 hours :worthy: hows that for a valve eating honda :ride:

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If its a used 05, do a proper rebuild and it will be running strong again for you.

Replace the piston/rings. Send out the head to get the guides checked and the seats cut, if you do not get the seats cut, the new valves will not last. Then you want to put in new seals, valves, and springs as a minimum. It is good if you replace the cotters and retainers also. The retainers can wear.

I know I have said it a lot, but I'll say it again... Hone the cylinder and do the dry rebuild method - your bike will run stronger and will be cleaner inside because of proper ring seal.

Here is how:

Hone the cylinder (ball hone or brush hone) in soap/water. Clean out with break clean and paper towels until there is no black on the paper towels. I have a 3.5” ball hone in 180 grit.

Wash the piston/rings in soap/water, spray off with break clean and let air dry.

Install the rings on the piston. Use proper ring staggering - follow the manuals staggering method - Be really careful not to get any oil residue on the piston, rings, or cylinder. Keep your hands wahsed

Install one clip on the piston. - the right side one.

Install the piston on the rod, use a light coat of oil on the wrist pin only.

Install the other clip, be sure not to get any oil residue on piston/cylinder.

Install the piston in the cylinder. Compress the rings with your hands and very carefully install it. Be sure that the oil ring doesn't bend over.

With the motor together, and no crankcase oil rotate it 50 times. Then fill with oil and check all fluid levels

Do not start the bike until you intend to ride it. Start it up, let it warm up good, go ride it hard with engine breaking, this will ensure the ring seal.

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Let me get this straight... you bought a used 05 and you've put 10-12 hours on it right???

If you're asking me, I'd do the works while I was in there.

No you took it wrong. I bought it in 04 brand new. Have only put 10-15 hours on the motor.

I did a valve adj (shimmed) at 10-12 hours.

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And as far as running strong, the bike is pretty new!!! Only 14-18 hours on the motor in total and it pulls real hard all over when the valves are on! You really think I should go through with all that stuff? I've never honed and haven't looked into getting my seat cut? Want to elaborate?

Also, I can get a deal through wiseco on parts. Should I go titanium or steel for valves? Also, do you think I should go with a high compression piston?

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wait wait wait, hold the phone. There is only 14-18 hours since the last rebuild? in that case its usual for the valves to move a little bit when they are breaking into the seats.

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Make sure you get the seats cut - new valves will not last if you don't -- get someone reputable to do this -- Agentsmith racing does that.

If you can get a deal with the wiseco stuff, go with it. I would go with the steel valves because they will last longer than ti, and their 13.5:1 piston - you can use 91 or higher pump fuel with the piston and it will give you a nice boost of power. - Just follow the dry method for rebuild.

Make sure you get the proper springs for the steel wiseco valves - wiseco should have the spring set. Otherwise Ron Hamp has an excellent Ferra spring set he uses with his valves that can handle the steel valves.

---------And if the clearances go almost to zero or zero two times after a couple of rides that is not normal nor is it normal break in for valves. Valves may move at most of around .001" when seating in.

---Make sure you keep up on airfilter maintenance - it is crucial for valve life, here is how:

When you change the filter check with a good light to make sure that no dirt fell in and also check with your hand. Always use break clean and a paper towel to clean it out. -- Make sure that the filter is in good condition, the OEM ones like to come apart at the seems on the inside after not too many uses. -- Make sure the filter is oiled properly with a good airfilter oil such as Maxima FFT or Belray -- And always feel all of the way around the airfilter to make sure it has a good seal against the airboot. The bottom/bottom left side sometimes doesn't seat properly.

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wait wait wait, hold the phone. There is only 14-18 hours since the last rebuild? in that case its usual for the valves to move a little bit when they are breaking into the seats.

No there is only 14-18 hours on this motor since I bought it new.

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