What did you do to your bike today?
- Thread starter jackson409
- Start date
Why the bent in the middle, flow is going to remove it. Should have been free standing.
Maybe that one hasnt been around in enough numbers, but I have yet to hear of a 450 which has valve related short time issues. Hard to get away from OE for me if that is the case. I have the hardest time going to a valve spring with higher tensions, for the load it places elsewhere. I don't think you feel the softening of your low or midrange power on the 450 but the wear factor would be a consideration for me.
Most high tension springs are progressive rate meaning about same seat pressure,, to keep valves being beatup on the face,,On the other hand your locks will be beat in the retainer maybe over a bit of time. With over head cams and the caps that hold them will take most the beating, along with some chain abuse,, oem is the way to go for longevity and time wear, and really will run about the same. "Unless u have a monster cam profile. For some drag racing etc.
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When you look at lift compared to base circle, pretty much anything I find on even the air cooled single cylinder cams falls into the moster bracket if you compare it to most of the automotive applications that I have been familiar with in the past. The first higher performance cam I put in anything was in 1966. It went on a honda s90 and was a Harmon Collins, complete with several sets of timing buttons. (that was a very nice set up to learn such things as "degreeing" on.) It took a set of 'stiffer' springs. The first thing I noticed was fewer windings, and even a 15 year old who knew anything at all about physics immediately figured out why. It also made sense that the same gauge of wire would indeed be stiffer that way. So anyway, in went the cam, in went the specified springs and up went the fun. A few months later I had reason to put the stock cam back in and I left the stiffer springs in and put the stock cam back in. The poor thing had about 7 hp stock, and less than that with the stiffer springs. My piped high compression piston rig would lose about any kind of race to a stock engine with those springs!! Not much has changed, the "faction" springs I put in one crf250 worked nicely with the cam they were specified for, under a stock cam, you lose though. So I probably have always picked cams a bit different than some of the people I know do. There are some creative cam grinders out there.