250R to a 310R questions

[Swinger]

I am slowly putting together my first R and would love to run a 310 kit. I have been looking around the site here for info on what all needs done to achieve this and have come up empty handed. I am always looking at the motors on evilbay but just dont have that kinda cash to drop in one shot.....until income tax:naughty:!!! I would rather do it myself because I take alot of pride in that kind of stuff as Im sure alot of others do. Does anything need done to the bottom end for this? What kind of rod do I need, long rod or can I use a standard rod? Any info on these would be appreciated greatly! What does an esr 310 kit usually run $$?

[sbjones73]

ok i will try and answer your questions here. i hope i get them all right
1) nothing needs to be done to the bottom end.
2) u can use the standard rod.

esr has them for 499 right now. but the porting cost like 100 extra, bilolet exhaust (if u wanted) extra etc. just go to eddie sanders racing and check it all out. or call. when i called they answered all my question. they even clued me in on jetting for the carb i am running.

good luck

[ceaserthethird]

I have a 310 Cylinder kit I'm selling, Send me a pm for details.

[Swinger]

Thanks guys. How often do you run your 310s, daily rider?? Just wondering how reliable this would be also?

[Swinger]

PM sent ceaser!

[sbjones73]

i should be getting mine here in the next couple of days. i pretty much only ice race. so i can't really tell you how reliable. but as with anything, it is how you treat it i would guess.

[Swinger]

You got a point sb!! Mine will be a daily rider ( well as much as possible) and tearing up coal hills and spanking those 4 wheeled contraptions every chance I get.:p

[pcs]

you can daily ride an esr 310 kit and they are reliable. a few guys i know have had esr kits for a few years. i will say the bigger 370 and 420 kits arent to reliable but you arent going that big so youll be fine. if you are going for more power, i assume you do bc you are buying a big bore, get it ported, with out the port they do not make good power.
long rod kits are suppose to make more power in the higher rpms vs the short rod. if you do a long rod conversion, they some kits require you to use a spacer plate at the base of the cylinder.
last month went out to take a few 250s (riding friends) to get dyno tunes and the most power came from an ftz ported honda cylinder. quick specs
85 250r ftz long rod conversion, ftz drag port, esr reeds, 39 pwk,100 octane, crappy fmf pipe 49 whp
88 trx 250r 330 esr kit, trx 5 port, trx 5 pipe, esr reeds, ported 38mm air stryker carb, 100 octane, 45 whp
89 trx 250r 310 esr kit, trx 5 port, fmf fatty, v force reeds, bored out 38mm pj, 91 octane, 42 whp
89 trx 250r stock cylinder, 38mm pj, fmf fatty, clamp on k/n filter, 91 octane 37 whp ( not mine but it was there and used as a baseline.)
not to impressed with the factory esr ports and honda cylinder made more power. the big bore did have a flatter torque curve but out on the sand dune, the ftz 250r will just eat them up and with a +8 swinger it will still pull that front tire up easily in a drag race.

[Swinger]

Thanks pcs! Alot of good info there and it helps alot!

[RIDE-RED 250r]

I would hesitate to convert to the long rod set up. You will have to run the cylinder spacer, and on a trike, there may be clearance issues. I don't know this for sure, but I have an ESR 350 kit on the way, and have been told by a couple of members that even with the short rod, there are sparkplug clearance issues. Mainly it's due to the ESR head not having the angled sparkplug hole like OEM.... I can imagine the cylinder deck being .250" (or whatever thickness the spacer is) would only make the clearance issue that much worse.

Maybe someone here has tried a long rod with ESR head in an ATC and can shed some light????

Just stick with your short rod...That's what I'm doing.

[Swinger]

HMMMM!!! Anyone????

[KASEY]

i have a 350 pv in a trike,.,, i think if it was taller it would be a pain in the butt!! everything is pretty close now.

[RIDE-RED 250r]

i have a 350 pv in a trike,.,, i think if it was taller it would be a pain in the butt!! everything is pretty close now.

Am I correct to assume you stayed with the short rod Kasey?

[deathman53]

I had spark plug come from the middle(not angled), actually 2 of them. On a 85 frame, you have to grind it to clear the boot, 86 frame it fits better, but still hard to do. One was a esr 330 bolt-on(long rod w/ spacer plate) other was a stock cylinder(w/ spacer plate and cool-head).

[Swinger]

This is going on an 86 frame but didnt think there was a differance in them.

[RIDE-RED 250r]

Deathman53: sounds like possibly the main reason you had clearance issues was because you converted to the long rod setup??

Which is a good portion of the reason I chose to stick with the short rod setup. No spacer plate=shorter topend=more spark plug clearance.....

Thanks for clarifying! :beer

[bannedbrraap]

BR8ECM ngk plug will fix all clearance issues!!....I have a Puma in mine and thats the plug i use, lots of room