Is there much difference between the 250R CT 310 big bore kit and the stock cylinder? How does the 310 run?

 

The guy i was going to buy the 310 ATC motor off of.

This is what he told me. When the trike was running he was on a paved road, he had .125 aluminum wheels on it. He nailed and tore the insides out of the rims.

I don't know if he was exagerating or not. But it sounds like brute power to me. He was a big guy too. 300 lbs

 

yes the ct 310 kit is awesome, power is greater than a 250,power on tap all the time, it is almost like ridig a four stroke cause you can short shift it and it takes off.. the ct cylinder is vey nice. it has 100% greater cooling, replaceable domes in the head and is awesome. i would reccomend this kit to any body, i love mine. a bit of advice: make sure your bottom end is tight before you buy a kit!! allen knowles will inspect yours for a good price. from experience, i ruined my bottom end on one of my kits cause my bottom end could not take it, even when i thought it was tight! also very important to follow ct's break-in sheet! good idea to buy the complete power package,run better and cheaper. let me know if you have any other questions on this kit,be glad to help, happy motoring!!

 

First off, do the math. The CT310 kit with it's 72mm bore and 72mm stroke IS A 295cc ONLY kit. The 330 and 350 kits are true to form--mathmatically speaking that is. I HAD a 310 on my R, when it ran it was fast--NOT A BRUTE THOUGH. It sheared the intake side of the sleeve's skirt OFF and filled the crankcase with debris. The sleeve is quite thin, since you are boring it from a 66mm bore out to 72mm. You take 3mm off EACH SIDE(the RADIUS). In Duncan Racing's catalog, they list the Pro-x/CT cylinder's as 70-75% as reliable as the stock cylinder. This probably also takes into account the HUGE intake port that those poor defenseless rings have to pass by on occasion(that's sarcasm). Without a side by side comparison(with the same compression ratios, same fuel, and other variables being the same), I CANNOT TELL MUCH DIFFERENCE in the CT 295 and my current motor. Mine may rev more now and not vibrate as badly. The CT 295 kit's powerband may start a LITTLE sooner. What I'm trying to say is simple--If you REALLY want more power go with the 330 OR EVEN the 350 kits. You will see MUCH MORE of a change. Be prepared to rebuild more often though. I prefer reliability--If you read my specs I went BACK to the stock cylinder but added all the bells and whistles to enhance HP while retaining absolute reliability! Good Luck with your decision.

 

After reading the prior posts, I have a few things to add & comment on. I have a CT/Pro-X 310 cylinder on my R, but am, by no means, an expert on the subject. From my experience and that of friends who run the cylinders, they are rock solid reliable, as long as they are properly cared for. Feed them the proper octane fuel and high quality pre-mix and they last a long time. As with anything, proper maintenace will take you a long way. The bottom end you bolt it to does need to be in good condition to take the additional power. The power difference between a 250 and a 310 is night and day. There is a large increase in torque and hp, although you do lose some revability due to the heavier piston. Geared the same, a 310 will top out roughly the same as a 250, but it will get there much quicker. A 330 or 350 will produce more torque and hp, but will rev even slower than a 310 because of the piston mass. Properly tuned, any of the Pro-X cylinders flat out haul.

 

I just put a CT 344(350) engine in my bike and I was highly impressed! It can walk away from my other 250R which has every engine mod but porting. As soon as I shift into 2nd gear it would immediately pull about 10 lengths on the 250. This 350 engine will definitely pull the front wheels off of the ground in any gear. It digs trenches in the ground when you take off it has so much power. I can't wait to square off against my neighbors banshee, he thinks his bike is unbeatable. He is going to be pleasantly surprised when I walk away from his Banshee in 2nd gear. I say skip the 310(which will never be a 310) and go straight to the 330 kit. That way, there will be no confusion about power gain because the 330 has about 15 more HP than the 250.