Cleaning up ports

[Racerx63]

Hey guys,

Gotta question, I received an 86 250R that was completely stock except for a silencer. I believe it even has the original piston in it. I am going to put a new top end in it but have a question about cleaning up the ports. I don't have the money yet to send it out and have it ported but was thinking about just cleaning up the casting flash. Not really take any aluminum out but just clean it up. Would this be beneficial or should I just wait and have it ported?

Thanks.

[Racerx63]

Sorry I should have added that I have added a FMF SST pipe for it.

[beerock]

its not that hard to grind down the sleeve and match it to the aluminum cylinder. you just need a carbide bit and a dremel. YOUR really suppose to use one of those 1/4 HP foredom porting machines. because using a high speed dremel on the aluminum causes it to heat up and become brottle. the foredoms allow you to spin low rpms and still cut the metalout without heating up the aluminum and changing its molecular structure(to brittle).

with that said u can either wait for a guy to port it that way or just dvie in and do it. Id say go for it, porting with a dremel and WAY cheaper then a foredome set up, were tlakin 700+ bucks.
While your in there you can cut down the transfers a bit too for some extra power. that asnd matching the sleeve will make you happy.

you could try to do this to the tranfers and intake if you want to get into it :eek2:

youll see that the stock porting looks NOTHING like this stock jug ;)

[Racerx63]

Thanks Beerock for the reply, I am not going to take very much out of it as I would be afraid of getting it wrong and killing it. I was just thinking if I cleaned everything up it should help get some more power out of it. Do you think the gain is worth the effort just to clean it up?

I know to leave the intake rough and the exhaust pretty smooth. Reading on McDizzys about porting has made me a bit timid about it.

Thanks,

[papatrx]

Be careful not to take any metal off the floor of the transfer or exhaust ports this will affect your timing and you do not want to have your port floor extend below your piston at BDC. Actually I would recomend you wait and have someone with experience do it since you can easily take out the chamfering to the port edges which will cause more ring wear. Porting done incorrectly can take away as much performance as it can add when done correctly. While you are trying to match the sleeve to the port it would be easy for you to get the ports out of alignment with each other. When you take it to someone to have it done, if they won't give you the exact specs and details of what they intend to do go to someone else. Also, they should ask YOU what YOU want and how you ride not dictate to you what they think you need.

[Racerx63]

Thank you for the reply I think that is what I am going to do. I'll just wait and take it to some one who knows what they are doing.

Thanks again.

[Racerx63]

Unbelievable, I pulled the jug off it last night and the piston is the original piston from its initial assembly. The piston is 18 years old. It did not even have any carbon build up in the head and top of piston. You can tell it was worn though.

[twisted threads]

Cleaning up your own ports isn't that hard..... but if you start takeing out alot of metal you could ruin your cylinder to were it would be no fun to ride. If you wanted just to clean the ports, I take some sand paper and nock off the edges and for the exhaust port you could just polish it up by going to a finer sand paper. I don't how much more power you will get out of a stock cylinder by just polishing it but im sure you would get some.

[zedicus00]

dont make the intake and exhaust floors and walls completly smooth. match the ports but leave texture on the flat areas, it is there to creat turbulance. the best engine builders add texture after the do a port job. if i still had mine apart i would post a pic. it actually helps to the turbulance keeps the fuel atomized better and it burns more thouroughly

[JTRtrx250r]

I gotta say it would'nt hurt to clean up the ports, but as stated ..he can ruin the cyl and lose power if he dont know what hes doing and tries to fully port it.

my intake is fairly rough, but my exhaust ports are as smooth as a baby's ***,.. I mean fully polished!!, I know FTZ does this also along w/ a few other big names

[Racerx63]

I am not looking to take any great amount of material out but just round off the sharp edges and get rid of some the casting flaws. There are some ports that do not line up with the liner. I might try and just form that a little just to line it up. I will leave the real porting to the pros.

Thanks

[papatrx]

I know your dying to get in there and smooth out what looks like flaws but be very careful. I have 3 boys that are continually wanting to start cutting without first measuring and planning. If you change the transfer port angles you can change the way the cylinder is filled with the fresh charge coming in thereby doing more harm than good. If I were you I would leave the intake side as it is and maybe clean up the exhaust some, but don't expand the height without measuring what your duration is now. Also try not to take the chamfer off the edges. Spend some time port matching where the exhaust flange matches up with the exhaust port. I usually make the exhaust port smooth and only polish the first 1/8 inch from the sleeve into the port. Good luck and if you feel yourself rushing, make yourself stop for the day.

[Racerx63]

I sat and looked at if for an hour today and decided to not do anything. Didn't want to screw anything up. Just cleaned out the carbon and will send it out to get it ported later.

Thanks for the advice.