porting and polishing a quadracer
#11
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Im going to be getting my new setup running soon, 87 LT250R im going from standard bore 67 to 69 and from stock ports to fully moded from dicks racing. I bought this cylinder off of ebay fully ported and polished for 20 bucks it had a crack in the coolant front port so i welded it shut. i haped to have a 80 over piston laying around from an old lt project and thats the size that the cylinder needed. also i had it powder coated chrome the head cylinder. power valve cover and water pump cover, so we will see how it turns out, ill let you guys know when i get a good day to run it. Ill be taking some pics prolly this weekend you guys can be the judges
#12
#13
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The weld was on the outside water port in the front, even if it was on the gasket surface or any other im a professional fabricator and machineist lol. the guy that had the cylinder before me i think left straight water in it in freezing temp duuu who does that lol
#14
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it dosn't matter where you did the welding i would still check it. even if there is a littel bit of warpage it mwy not leak but it could rock a little bit and when it rocks it hamers on the case and causes cracks in your cillinder mainly on your mounting tabs
#16
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Doesnt porting your intake actually shift your power towards the top end? I know a lot of pro woods racers keep thier ports stock size and use stock size carbs for this reason. My 88 lt250r has stock ports,and i have a paul turner pipe and silencer and a k and n and its plenty fast
#17
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I took a clean up cut made the surface flush taking as little as possible, I always do on a rebuild just to make sure. not working anywear right now im in my 2nd year of college starting CNC. superevil yes porting does take a bit away from the bottom end but doing certain adjustments like a good pipe and you can adjust the power valve to comensate, it all depends I do alot of woods riding but not really tight trail kinda wide and clean
#18
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hey F250R. when your talking about timing the powervalve, to get more low end power you decrease the tension on the valve right? and opposite for top end power? say i was racing in an enclosed dome, which is a really tight supercross track, how far would i adjust the powervalve to gain more low end power, say right off of idle, if not 1/4 throttle?
thanks, Andy
thanks, Andy
#19
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your power valve should be closed at lowend creating a higher back pressure wich leads to low end, for high end you would decrease the backpressure so the valve opens at topend power so yes you r correct just fiddle with it a bit and see what your prefference is
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