Pipe Help/Understanding

[matt14c]

From what I have noticed a pipe setup for a two stroke is much more important and varies greatly as opposed to the pipes for four strokes which im used to. Im putting my rebuild together and the Bills Pipe that I have now is pretty beatup. I tried sanding it down and polishing it up but the better I got the finish to look the more dents, dings and gashes that showed up. With everything that im doing I dont really want to put this back on. For my setup I will give all the information I have. I have the CR500 carb. The eariler one not the ones from the newer which is the popular one. Boyseen reed valves with the 86 spacer. Motor is bored 80 over and from what the motor builder told me its a mild port just an all around not really set to much towards one side.

Now for the pipe questions. I dont really want to keep the motor bored that far over. I would like to put it either back to a nice 265 or 310. So with my current setup in order for it to run properly will I need a big bore pipe or a pipe that once I go down in bore will it be useless? I want to get together before I open the motor. The motor ran well before the rebuild and I have alot of open ended questions so if it doesnt start I dont want that to be one of them. So I would like to get together then do the motor work over the winter so I have time to do it right.

I see there are low to mid pipes and top end pipes well is that all pipe or does most or alot have to do with the internals with the ports?

Im not really sure what to ask I would just like someone to enlighten me on the two stroke situation so I have some clue and dont look like a complete dumb *** when I go to have this stuff done/replaced. Any recomendations on what to do? Put this ugly pipe on have the bike running then do the motor overhaul and get new pipe then? Is there such thing as an in between pipe that I could get now and that would work with what I want to do?

[cdrookie]

put the old pipe on and run it till you find a good deal on another nice one. .080 overbore isn't much, a big bore pipe is usually for 330-350cc+ motors. find yourself a nice sparks mx, pt 89 race, or lrd. if you ride in more open terrain or dunes a esr trx5 or 5r would be a good choice.

[86 Quad R]

i'll 2nd that but would like to add that with the cr500 carb and what i believe is a play porting that you have i'd later look at getting a pt mx or something like an esr 7. then again it all depends on what type of riding you do the most of. :cool:

[IcutMetl]

A lot of people on here will bash on the FMF products, but I really like my Fatty pipe. It seems to have great usable throttle, and you can tell the meat of it is pretty widespread in the midrange. I'm positive that there's better pipes out there that are more focused to one area of the powerband or another, but for paying only $100 bucks for a used silencer and pipe on ebay, I could hardly go wrong.

You mentioned that you had the early CR500 carb; others on here may chime in here- that was the 38MM "PJ", wasn't it? That's the carb that was on mine when I bought it; once tuned in it ran very well and I have a similar setup as you.

You also mentioned that your motor was bored .080" over, but you didn't want to keep it bored out that far. An .080" overbore should be a 68mm piston, correct? That should put you in the 260+cc range if I'm not mistaken. I would expect a 'standard' pipe to work just fine, even if you do go a bit bigger. I have a .060"/67.5mm bore & port and it seems to do just fine for me.