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I’m currently working on a project but i don't have the money to buy parts for all different bikes. what I need are measurements of the intake and exhaust lobes as well and the degree of overlap corresponding between the two. be sure if you have aftermarket cams to state that cam with the measurements.im hoping for a variety of cams as far as performance gearing goes. if somone could help me with this it would be greatly appreciated.

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what bike are you working with? what your going to find is different manufactures may list their specs at, zero lift, or 1mm lift, or .050" lift . This makes side by side comparisons a guessing game.

If your working with a particular bike best thing to do is measure it yourself.

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im fully aware that that the so called grind of one bike is not what you want for another. the reason i ask for variance in models is that im working in new grounds and would like some numbers to begin crunching for other models. as far as a particular model that i would like most the 2010-2011 kx 250f and 450 is where i have begun at as kawasakis are my bike of choice and if nothing else would like some measurements of some aggressive race cams for either of the two.

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Take this question over to the KXF forums and ask there if anyone has changed their cams and could give you the specs from the grind card. You're more likely to get a greater number of responses there than here. The OEM manuals will only list lift (and even then you have to calculate it), and that only as a way to measure for cam wear. Lobe centering, duration, and the rest of the profile are never given.

Otherwise, you're going to have to look through some catalogs or talk to some cam grinders.

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Hotcams and Web cams list the lift, duration, and lobe center of all of their cams on their websites. However, these numbers only tell so much about a cam. The ramp rates and such are almost always kept a tight secret. If you are just looking for lift, duration, and LC then those numbers can be found all over the place.

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Hotcams and Web cams list the lift, duration, and lobe center of all of their cams on their websites. However, these numbers only tell so much about a cam. The ramp rates and such are almost always kept a tight secret. If you are just looking for lift, duration, and LC then those numbers can be found all over the place.

Lift and duration tells you the ramp rate. High lift on short duration is a fast ramp rate which is very hard on the valve train. LSA is the overlap. Cams are a lot simpler than most want you to think.

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Lift and duration tells you the ramp rate. High lift on short duration is a fast ramp rate which is very hard on the valve train. LSA is the overlap. Cams are a lot simpler than most want you to think.

Not completely. It may give you an idea, but you can have two cams with the same duration and lift, but very different ramp rates, the profile of the cam lobe itself is what can vary, and this is almost impossible to find information on unless you get your hands on a cam and measure it out yourself.

Lobe separation angle is not the overlap either, however you can find the overlap if you know the durations of the intake and exhaust, and the LSA. The LSA is just the angle from one lobe center to the next. You can find the LSA by averaging the lobe center angles. I prefer to deal with lobe centers themselves rather than LSA's since you can retard both cams the same amount and get the same LSA, but a very different performing engine.

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Lift and duration tells you the ramp rate. High lift on short duration is a fast ramp rate which is very hard on the valve train. LSA is the overlap. Cams are a lot simpler than most want you to think.

Lobe split angle only gives the overlap if the duration is known, and even then, the lobe may be asymmetrical, which will throw your calculation off.

Lift and duration will only give you the valve acceleration rate ("ramp rate") if you make the clearly faulty assumption that the lift rate is constant from closed to open to closed. All one need do it compare the full lift curves of a flat tappet cam for a typical V8 to a roller cam for the same engine with the same L/D. Totally different.

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i also must agree with the 1987cr250 as complicated and persice as cam timing is you just need to think about the variables your controling. the intake lobes allow for an opening of a certain time and lift to allow a certain mass of air in the cylinder. the overlap is how long engines allowed for an explosion then the exaust valves open repeat the same as the intake letting gas out.

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