specialized169 Posted August 16, 2006 i had kw put in my 2004 crf 250 i have been riding it for about 2-3 weeks now and my valves got really noisy so decided to check timing and and valve clearance. Well i found out all my valves were way outta and on top of it they loosened up one of my exhaust were almost a tenth of an inch outta spec i couldn't believe it still kicked started and the other one was only like 3 thousands of and in. outta spec. then my intakes where both like 2-4 thousands outta spec. MY REAL QUESTION IS WHY DO THEY LOOSEN UP Share this post Link to post Share on other sites
sealusion Posted August 16, 2006 They settle in some, but I have never heard of that much movement from new. Did you resurface the seats? Share this post Link to post Share on other sites
specialized169 Posted August 16, 2006 they were done by a shop and they cut the seats and the whole nine yards he only did the head, i actually worked on the bike myself Share this post Link to post Share on other sites
Throttlejockey Posted August 16, 2006 They weren't set right to begin with I would guess. If anything they tighten, not loosen. Share this post Link to post Share on other sites
specialized169 Posted August 16, 2006 Do Guys Think It Could Be Due To A Bent Cam Or Maybe The Shims Wear Because Of The Springs Are Stiff Share this post Link to post Share on other sites
huffster Posted August 16, 2006 Did you replace the springs to match the SS KW valves ? If not, then the heavier valves have been bouncing and have again hammered the valve seats Share this post Link to post Share on other sites
specialized169 Posted August 16, 2006 Yes I Have The Heavy Springs For Kw Valves Share this post Link to post Share on other sites
dennit1 Posted August 16, 2006 Did you bench set them or did you adjust them with head & cam torqued down? They can not get loose by the seats getting hammered, they would get tight. Share this post Link to post Share on other sites
specialized169 Posted August 16, 2006 Exactly, Thats What U Would Think, I Dont Really Know I Had The Head Done By A Shop And They Said When I Get It All I Have To Do Is Bolt On So I Did And After About 3 Weeks Now Everything Happened As I First Posted So Maybe He Didn't Torque It Down When He Measured But I Always Do When I Check Clearances Share this post Link to post Share on other sites
Bodyman Posted August 16, 2006 Exactly, Thats What U Would Think, I Dont Really Know I Had The Head Done By A Shop And They Said When I Get It All I Have To Do Is Bolt On So I Did And After About 3 Weeks Now Everything Happened As I First Posted So Maybe He Didn't Torque It Down When He Measured But I Always Do When I Check Clearances So you did not recheck the clearnces, you bolted it on and rode it??? Anyway to get a tenth of and inch you would have lost a shim. That is a big gap. Maybe .010" and .003. If the exhaust was off split like that then they are not set right from the start. The valves almost always tighten up and never loosen. The Exhaust rocker could have bent... Share this post Link to post Share on other sites
nate_powell Posted August 17, 2006 mark baldwin(pro quad engine buider) told me to put only stock in. he said they are the best and thats what tim farr uses in his quad. Share this post Link to post Share on other sites
Dan CRF250 Posted August 17, 2006 mark baldwin(pro quad engine buider) told me to put only stock in. he said they are the best and thats what tim farr uses in his quad. stock sucks, and these arnt quads .. lol so theres your answer Share this post Link to post Share on other sites
ShadyatBest Posted August 17, 2006 Do Guys Think It Could Be Due To A Bent Cam Or Maybe The Shims Wear Because Of The Springs Are Stiff cams do bend very easily Share this post Link to post Share on other sites
MXER43 Posted August 17, 2006 cams do bend very easily WHAT? Cams don't bend easily, cams and shims are two of the hardest parts in the head. It is possible for lash to get bigger when the seats are coming out of the head. I have seen this happen a few times, it sounds impossible but can happen. When the head gets over heated a few times it may loose some of it's original hardness and not return back to it's original size when cool, then when it gets hot again the amount of crush needed to hold the seat in isn't enough and they can vibrate out. If your not careful the seat may come all the way out and destroy the head. The only way to know if the head is cooked or lost its hardness is by doing a hardness test. This fact goes to show what strange vibrations occur in the motor, even with the valve pushing the seat in it can still vibrate out, it's pretty crazy. Share this post Link to post Share on other sites
specialized169 Posted August 17, 2006 my seats were just reshaped i didn't have new seats put in he just reshaped them Share this post Link to post Share on other sites
