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kibblewhite springs with titanium valves

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Hey all. I bought an 07 yz250f from a pro last year for my son, well replacing the piston I found a head that was different than our other 250f's. It was ported and polished and had kibblewhite dual spring and titanium valves.And Fancy in take cam.. THIS BIKE RIPS. I am thinking of duplicating the same combination on my 07 yz250f. The big question is.. are kibblewhite springs not too strong for titanium valves?. My sons bike tell me no..wounding if any one else is running this combination?

Thanks

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If its the spring kit for the stainless steel valves you can't use it. They are heavier duty springs than stock made to be used with the stainless valves because they are heavier than the stock titanium valves.

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They most likely put the stiffer springs in because the cams were probably a high profile cam, without the stiffer springs there may have been valve float. I Run the procircuit springs because I had webcams.

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May want to check with Kibblewhite. Pros may put new valves in every couple races, Factory riders probably get new valves every race, so they may not care if the springs are too strong.

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I'm not a big fan of heavy springs even with modified cams. We run stock springs and the lightweight retainers that we sell... that's the best combo.

The 4mm stem on the intakes is very small to be putting the added pressure on them, potential for failure.

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I think "intensem1rider" is on to something with the intake cam profile. I am going to hunt the guy down I bought the bike from and ask him (if I can find him). I know he will be at the Seattle suppercross but that's a month away. I have my head at the machine shop getting the seats ground now.I have the kibblewhite springs, I'll order the valves to be on the safe side.

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Well I talked with the person I bought this bike from this week end and "intensem1rider" was right...the kibblewhite springs were installed because of the profile of the intake cam..stock springs cause valve floating on radical cams..this guy builds a lot of race bike and knows his stuff..he was very helpful..he said that it is ok to use kibblewhite springs with titanium valves but will make no difference unless your cams are higher profile...I've had all the valves removed from this head when I replaced the piston they where in perfect shape... on my other bike I run a 290 big bore with hot cams and find it has the big bore rpm blues.. I got my head back from the machine shop today and am going with the bibblewhite springs,stainless exhaust and titanium intake valves..hopefully that will smooth out the higher rpms..

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let me know how the bike is after hte head work if u still have the 290 kit installed...like a comparision of wether u like the 290 with head work done vs the 250 with headwork done....idk if i wana rip my big bore out put a high comp piston in and get head work done.

mine just doenst seem as strong as i would think it hsould be...def stronger than it was before but in comparison to auburn's stock 07 i thought it was bout the same maybe the 07 actually stronger

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I found my big bore didn't wake up til I put a JD jetting kit in. I will be putting my new head on after this week end so look for results coming soon. If I was on a budget (big bores are expensive) I would just go with the high compression piston, stage one intake hot cam and do the port and polish routine. I am over 200 lbs so the big bore gets my fat ass up to speed faster and is better in corners but for the price is not that much better, my sons bike is smooth and fast through out the rpm and does not peak out as soon.

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