I just rebuilt my topend busted the old piston.I didnt run any thrust washer on it.Well i had it bored to .80 also had my head milled .20.Also had some trail port done.That i end up cleaning up. Not the best in my opion.I finally got my hours in on break in and opened it up for the first time this afternoon. Big question is since i ported the motor will it need more gas by rejetting it or will i have to go down. Also shaving the head would the jetting have to go up or down.It seem the Blaster everything you do to them it seems you go up in jets.Seem like you go down on the Lts.Im confussed on this.I rejetted before i started it i was lean before it blew because of the cold.But it ran like crap when i open it up.Its rich or the power valve nots right.Had this problem last rebuild. Which it was the power valve..But is it up or down on the jetting on lt250r when doing mods.Help me please.Thanks in Advance Brian
You need to sort out one jetting circuit at a time.
What is not running right exactly?
Will it idle on it own? What about half throttle? How does it run? Full throttle?
It idles good and runs good till half way.Its like its has no power on the power band.Im going to mess with power vavle setting today.If that doesnt work i will mess with the jetting.Also i think the clutch might have a issue .Il post back later after i figure it out.
ride bike with 1/4 throttle, then see what it does. does it rev up, bog down or hold steady rpm.
try that at half then 3/4 this will help you find the right jets you need to be running. then try doing a plug chop
once you get closer to where it should be running
It is the power valve it is frozen will not move. I cant even move it with a screw diver
not sure of all the history on the machine but I just got done replacing a lot in the clutch side of the motor, specifically the power valve actuator and the ball bearings behind it. if either is out of spec it can tie up everything. also check those damn plastic clips on the rod. they like to break and get wedged in the clutch cover. just a few things to check while you're in there.
Did you take it out and clean it before you put everything back together with the new top end? Did you use the rite bolt to hold the retainer, its a special bolt that won't distort the retainer. Is the retainer installed in the rite position?
When the old piston went bad it broke above the exhaust port.Most of it got above the piston and went up in the head.Their was a piece i couldnt find.Split the case it wasnt in the bottom of the motor.Well i put it back together and then i got my head back threw the power valve in and move it .The spring moved and power valve didnt but i didnt really check it.Just felt the spring move didnt watch it from the bottom and put it back on.When i took it back off that piece of piston was behind smashed it.So i took it back of and grind the piece out which i thought i got it .I put it back on and it still hung up.So i took it off again and really took my time grinding and polishing it up.Now it work great and the bike runs great.I need to throw my 38 pwk and get
a better pipe for it to finish it off.Saving my money for a new paul turner mid range pipe.
You can get an SCP 250 pipe for $480, it is by far the best 250 pipe.
i'm running a SCP/Q pipe and i agree. IMO best pipe hands down for a 250.
Who make the pipe you guys are talking about.Also were do you ride.I live in the mountains West Virginia their isnt many place you can open it up all the way.So you need all the low end power and midrange power you can get.I also heard the Q and the other huge pipes only really get top end power and its is great power.But its not what im looking for.
maybe put the powervalve in there without the bearings or anything and see how it moves in the cylinder. clean it up, check to see to bearings are straight on the pv. oil it up a bit. and polish a bit too never hurts.
The power valve is fine now.I fix that problem.The bike runs strong now.I just want a better pipe then my fmf.How is the Scp pipe on low end and midrange .