ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Aug 25, 2018 6:40:49 GMT -5
because I have access to a full machine shop now, and the owner is trying to make a very fast GY6 bike ( starting with 50 cc) , I wonder if there is any one interested in testing some one off cams. Please read the last post in my “new project” thread.
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Aug 25, 2018 7:59:43 GMT -5
Deleted lack of interest
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Aug 29, 2018 7:48:16 GMT -5
Deleted
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Post by jbjhillbilly on Aug 29, 2018 11:39:04 GMT -5
Just saw this. Kids just started school this week, so it’s busy around here!
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Post by Sir Scoots-A-Lot on Sept 7, 2018 19:57:35 GMT -5
because I have access to a full machine shop now, and the owner is trying to make a very fast GY6 bike ( starting with 50 cc) , I wonder if there is any one interested in testing some one off cams. Please read the last post in my “new project” thread. so I searched google awhile ago and there are a few options of existing cams for different profiles, i.e. good low end or good top end cams, most are lised as a9 a10 a11 a12 etc. I also found an adjustable cam! your best bet might be to get the adjustable cam to test all different profiles then either buy or make a version of whichever profile you find best on the cam with adjustable lobe timing. if I had a bunch extra money I would do that |
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Sept 7, 2018 20:51:12 GMT -5
I have tested a number of cams. I reprinted the results of some of that testing in the Gilxal cam post. The odd part is that these so called performance” cams actuly have les duration and many cases les lift then the stock cam. First, I see no reason to limit the vale movement (lift) to .183”
The cams I have tested would fall under the class of “ torque grinds”. The stock motor puts out about 3 hp at 7500 rpm. I believe that the design push behind the “ preformance” cams was to create more torque while keeping the same 7500 rpm power peak. I’m also guessing that these aftermarket cams all have the or less lift as stock is that they all start with the same billet. The most lift that core can give is .187 ( if you stick with the same cam circle). There is room for way more lift befor you get spring bind or hit the valve guide. I also believe these cams are way to retarded to move that power band up into the 8 or 9,000 bracket..
Of course I could be wrong. That’s why I’m making up some samples with more lift and. More duration. Of course we will be testing them in the bikes I have access to. But the engines in those bikes have a lot of machine work that is way beyond the normal bolt on goodies, and I would love to find out if my designs work well with engines with bolt on goodies, and hopefully with different compression. From the posts I’m seeing there are guys running cray high compression. Well over the 200 psi that I consider “safe”. I’m guessing these engines are running very hot. Like close to meltdown hot. If my cams do what I think they will, we might be able to bring those temps down a little while producing more HP
As I said, the aftermarket cams I have tested are more like “torque” cam grind, except that every torque grid cam I have ever had contact with have always had MORE lift then stock. So that is the first thing I’m going to change
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Post by Sir Scoots-A-Lot on Sept 20, 2018 21:26:13 GMT -5
I appreciate reading your threads on cams Ratdog. Seems like so many people just blindly go A9 and claim 1 or 2 mph gains although after reading your results of examining it I wonder if these people are just being optomstic or expect to see gains so they get a tailwind and report a 2mph gain. I am still working on my scoot in CT for another month or 2 and riding it quite possibly until it snows...so if you do want a cam tester I have a 139qmb in working order that I wouldn't mind using as a guinea pig
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Sept 23, 2018 13:41:10 GMT -5
Thank you for your interest! I was thinking I was talking to my self! And thanks for the offer, but I’m really looking for testers that have moved their bikes and already have greatly improved preformance. My theory is that we have lots of great bolt on stuff for these bikes and the bottle neck right now is a cam! I believe that the cams you can buy right now are all designed to be “7500 rpm” cams. To get more hp, we have to move that power peak up the RPM range
One thing that is constant is that no one wants to admit they are wrong. So if they say they bought new muffler bearings, you can bet most will tell you it was a measurable increese in preformance
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