I have my 86 trx250r. I will be rebuilbing the engine soon (bore and hone cylinder, polish ports)
I want a low/mid range pipe, so I am look for some advise. I am also putting on a new carb,
38-39mm.

 

Are you looking to build a motor that is biased towards mid range power???

If that is you intention. I'd like to offer these suggestions.

Increases in compression along with getting the squish band properly set-up will increase low-mid range power. Also porting the cylinder for a mid range bias will always help. You could also bore the cylinder out to a 270, where the increase in bore size will help mellow out any "peakiness" that you may have in your powerband.

A aftermarket reed cage will certaintly help, especially when coupled with dual stage reeds that will provide crisp throttle response througout the power range.

I'd also like to reccomend perhaps running a slightly smaller carb size for a low-mid motor. A 35 PWK AirStriker will provide excellent characteristics at lower RPM's, but still allow sufficient power at higher RPM's. A 38 PWK AirStriker will also work, definately when coupled with the proper port job, compression increases, and reed changes. It just may not be super-crisp on bottom like the 35 would be, but would have a greater top-end potential.

I've had a motor done here locally by JSD Racing for a mid-range biased motor. To date it has been the smoothest, easiest to ride, but yet very potent motors that I've ridden. I had this done to my wife's motor.

For porting and head mods would be about $250.00, carb another $235, reeds only- $40.00, aftermarket reed block- $135. (Prices approxiamted).

LRD has a good mid-range pipe. You certaintly couldn't go wrong with a Paul Turner Mid-range pipe either. But on the few occasions that I have spoke with Arlan at LRD about that, he claims his pipes far exceed the PTR pipes. But then again who wouldn't claim they have the best...but I think that either pipe would be suitable.

 

Well, What type of power delivery you want will play a part in the best pipe. Although I love CT and have had much success with their work (1998 GFTL ATV Pro Champion) I would recommend the Paul Turner over anything else for bottom-mid power. They are smooth but have a good pull the only thing they don't do is rev out well but you said you wanted bottom-mid power. I have owned just about every pipe and silencer combination out there and The Paul Turner is what I would go with based on what you have said. Also, I don't know how well your motor will perform as a tuned package if you get porting, pipe, carb all from different places. Pick one, and get their complete package you will be glad you did. I hope I have not insulted anyone with this response. I swear by CT and think they do the best motors out there. But the Paul turner engines I have raced against have great bottom, arguably more than any other engine builder. That is my 2 cents.

CT250R...1986 CT310R , 1988 CT270R

 

CT250r, I am thinking about getting ct's 330 kit, do you think the performance would be best sticking with CT's pipe or going with another pipe now then putting the 330 kit on? Thanks.

 

We'll I am assuming that you have a TRX250R and not a blaster. The CT330 kit will give great torque but will not rev out quite as well as a 250 will. What kind of power are you looking for? smooth? hard hitting? screamer? The CT National pipe has a good burst on the lower mid and revs out reasonably well but not like the FMF fatty or even the LRD Team B will. The LRD is what I use on my '86 (CT310 kit) because with the CT it hit a little too hard and was losing traction on the track. Also the LRD revs out and gives a broader powerband. It really is what you are looking for personally as well as what kind of porting you have. I own 2 250R's both by CT and they both use 2 different pipes to achieve the same result: A smooth complete powerband from lower-mid to upper- midrange. I think that the short rod motors (like my '86) work better with a pipe that has more hit and more midrange oriented than the '88-89 Longer rod engines. (My '88 works best with an FMF "Fatty" pipe.) We'll I'll quit rambling if you have any questions e-mail me and I would be glad to help any way I can.

CT250R