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2011 crf450r starting issues/ not valves

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I have a 2011 crf450r i shimmed the Valves because it was getting hard to start iv done this several times but this time after doing so it won't kick start , it will only bump start and will not stay running unless I give it gas so I thought it was a fuel problem. I have set the tps where it needs to be and changed the fillter and the pump is working so I don't believe that's my problem and even tho I've shimmed valves several several times I had two other friends check them as well to make sure it wasn't something I did and everything has checked out in specs and in time but it is time to replace the valves since one is down to a 1.30 shim. is it possible the valve nicked the piston causing a loss in compression being the reason it will only bump start and if there are any other explanations for this problem other than the valves not being in specs is greatly appreciate the opinions thanks in advance

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Would you suggest stainless or titanium I herd stainless stretched less often then titanium but is harder on valuve terrian

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The valves don't stretch. The face actually erodes away when the hard coating has been breached and the whole valve recedes into the head. The stainless valves also wear, but they wear slower. The reason it wont kick start, but will bump start is the decompression mech retracts during a bump start, you build more compression and it fires.

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Thanks bud dose the I've heard stainless wears the valve seats and is tuffer on the whole valve turain is this a fact or not and if so what dose it effect

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Not really. The valve seats are so freaking hard that they're what actually starts the problem. The stainless valves are heavier. Some guys think they can tell or notice the engine revs slower as a result. Im dubious of these claims. Better springs are necessary for the stainless valves. The seats should be cut (touched up) but lots of guys just lap the stainless valves into the seats and roll it.

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