Big bore cylinder

[Pj Uptmor]

Do we have any opinions on big bore kits for the trx250r? Looking for a 330 or a 350 cylinder. The sphynx cylinder can you use a big bore exhaust or have one built for the sphynx.

[Tbone07]

Do we have any opinions on big bore kit for the trx250r? Look for a 330 or a 350 cylinder. The sphynx cylinder can you use a big bore exhaust or have one built for the sphynx.

Lots of good options for 330-350cc BB kits. ESR and CPI Sphynx cylinders are the most common. Sphynx being the higher-end of the two. Big bore exhaust needed for 350cc+. Plenty of big bore exhaust options.

If $$$ is no object to you......go with the Sphynx ported by your engine builder of choice.

[havinnoj]

I second Tbone's comments. 

Pro-X + ESR cylinders are great, especially for the money. 
Sphynx is a little better casting & port layout IMO, but there is additional cost for it.  Whether that is worth it to you, that is your call. 

Sphynx you can run standard or big bore pipes on the sphynx - like Tbone says, as you get to 350+ you would want to consider a larger stinger diameter (like the 350G pipe).