are the top of the transfer ports the ones that are offset height wise or the bottom the bottom of the port nearest the intake is lower than the front port is this the way they are supposed to be or vise versa

 

The transfer ports near the intake are the boost ports the ones near the exhaust are your main transfer ports they should open first by 1-3 deg. Somtimes with a pipe because of a pulse in backpressure you can put less of a angle on the boost ports. in other words your forceing the fuel towards the exhaust port you dont want fuel in your exhaust but you don't want exhaust in your cyl. so it's finding the happy middle type of thing. I am not recomending just saying somtimes this can make quite the difference. but never raise the boost ports just change the angle. If your mains and boost happen to open at the same time you may want to add angle to your mains and raise them to open 1-3 deg. sooner and leave the boost alone this will put less fuel toward the intake side to help compensate for the backpressure pluse of most pipes. this is all JMO. so if you screw up your cyl. dont blame me this stuff has worked for me in the past dose not mean it will work on your engine. I hope this helps anwser your?

2003 tb250 RcR stage 1 kit
milled
Jeff

 

thanks alot no i won't hold you responsible it don't bother me to screw up but the wife on the other hand hehe says why can't u just leave things alone and ride them the way they are and my answer never fast enough and never have enough power so i tweek them out might ruin a few things along the way but thats all part of learning new things anyway back to the ports both ports angle back towards the intake but the front part facing the exhaust looks like they are facing back alittle bit also is this where i want to angle a little bit towards the exhaust

 

Ok so your like me I have ruined cyls. messing around with transfer ports it's normally not a reccomend process. But I think I read somewhere on hear you built your own pipe so you may have alot to gain from this. port work has come along way with hours and hours of port mapping and computer software before the grinder comes out so for guys like us it's trail and error. can get expensive when you ruin your cyl. heres where I would start look at the center section of your pipe the area between the cones if its short you may benifit by aiming your boost ports toward the exhaust. Don't mess with the sides of the ports just the top angle and don't raise the port just less angle directing the fuel more towards the center\exhaust side of the cyl. if your center section is long then leave you ports alone and try a smallere dia. sliencer more backpressure if this helps heatwrapping the exhaust may also help. As far as i know theres not alot that can be done with the main transfer ports in a 250 to direct the fuel more than it already is away from the exhaust port if you don't have enough postive stuffing wave returning to the cyl the only thing you can do is more backpressure and pipe heat. But again for guys like us without extensive knowlage of that pipe and porting it's trail and error.I ruined the cyls. on my Rd400 twice with transfer port work but the thrid time what a diff. If you were brave enough it would outrun the other bike with the same pipes. and carbs and jetting. much smother power band.

2003 TB250 rcr stage 1
milled head 025
Jeff

 

Your absolute best bet is to put a 1mm spacer under the base plate and mill the cylinder top the same amount. It's really not good to start modifying the transfer port tops without really understanding how it works, The flatter you get the top the power moves higher in the rpm range. Without the sub-intakes and actual boost ports in the 250 jug, they lack for real performance gains in comparison to the 400 jugs. If you have the proper porting tools to get to the main and auxilary transfer windows, then just keep the factory angles and raise them some. You can even stagger the main and aux ports .5mm to keep the power wide. But in all reality you need to put a degree wheel on it and see where everything falls. The factory jugs can be off some and the blowdown duration (time from where the exhaust opens to where the transfers opens) also needs to be kept to a certain range. REMEMBER THIS: it is very easy as said before to ruin a jug with minor cutting in the wrong spot. And usually when it's been cut out it cant be put back in. Have fun,Bubba