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

 

if you did any welding on your cilinder check to make sure that were it bolts on to the case and where the head bolts on is still perfictly flat. if its not you will get gasket leaks.

 

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

 

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

 

hey what shop do you work at

 

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

 

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

 

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

 

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

 

ok, thanks buddy. I've been wondering how that works for acouple months now. just never got the ambition to ask anyone.

thanks, Andy