atc 310 vs atc 330r

[william16339]

what do you think is the beter deal. a atc 310r with trx 9 porting open airbox boysenen power reeds reed spacer and more...or a 330 with reed spacer trx9 porting open air box? i trail ride and drag so i would like something with tourque and topend..im guessing the 330 has more bottom end. let me know thanks guys! long live the honda atc 3 wheeler!

[3Razors]

I'd go with the 330 myself. It will have more everywhere. Just have to set it up right.

[william16339]

thanks true..but ware can i find a 330 kit thats not like 1000 lol?

[RIDE-RED 250r]

IMHO, you wouldn't want to run a spacer with mid/top porting. Spacers give you a little more low end and take away a little up top. So you would want to run a spacer on an engine set up for low/mid....

I have an ESR 350 topend (78mm) with stock stroke, TRX9 porting, ESR reedblock with no spacer and ESR ATC5 full exhaust. It really hits hard on mid and top. And with the big bore it still has good low end.

ESR offers a variety of big bore options and are the least expensive. Pro-x is similar but a little more, and top of the line big bores for the 250r (according to some of the best biulders for the 250r) is CP Industries. ESR has had some QC issues, but mine has done well for me.

There is ALOT of info out there. So do your research and make a well informed decision based on what you want and what your budget is.

[william16339]

thakyou! but ware can u findem cheap

[ceaserthethird]

You can't find anything cheap, Call BDT, ESR, Duncan racing, CT racing...
If your looking for cheap, have your stock cylinder ported.

They can give u ruff torque numbers & Hp Ect...

[william16339]

thanks everyone

[RIDE-RED 250r]

You can't find anything cheap, Call BDT, ESR, Duncan racing, CT racing...
If your looking for cheap, have your stock cylinder ported.

They can give u ruff torque numbers & Hp Ect...

Very much agree!!

There are some good builders who can work a stock cylinder to put out as much or more as most "off the shelf" 310's.

2 builders I know of who are really good with stock cylinders are BDT Motorsports and C-Leigh racing.

[pantera1975]

If you are gonna go the cheapest route have the stock cylinder ported. I have 2 ATC's one with a esr trx 9 ported 330 pump gas, esr exhaust,39mm pwk carb, 13/38 and the other is a fresh rebuild stock cylinder PSI racing HI-REV pipe from 1991 and a PSI ported cylinder for ice racing with a 38mm pwk 13/39. Both motors have billet exhaust flanges, 89 style clutch up grade 88-89 long rod cranks,no air box lids, less than 10 tanks of fuel since complete rebuild and v force reeds. Now the 330 is registers the fasted top speed with 13/38 switching from 37,38,39 dont feel different at all really. Racing side buy side from a 5 mph start or pretty much any speed or gear the 330 always jumps out 20 feet one the 330 get to 80 mph my psi ported motor starts to catch up but it never will because of being wide open long enough. I can lug the 330 in a corner slow down to 10 mph in 4th gear if need where the ported motor needs to be in 1 or 2. The 330 always is faster out of the corner. Both motors will need a good exhaust. Paul turner or ESR. the big bore cylinder need to be check over real well for trueness before assembly and it needs a 38mm carb which will run you $250 with a cable and jets, prob a different needle too.

[jadleybray]

Very much agree!!

There are some good builders who can work a stock cylinder to put out as much or more as most "off the shelf" 310's.

2 builders I know of who are really good with stock cylinders are BDT Motorsports and C-Leigh racing.

Really? Show me a stock cylinder BDT has done with something to show for it.