biggest bore/stroke kit for a 300ex?

[rm25x]

Just wondering what the biggest bore/stroke kit is out there for the 300ex. Did a search, but didn't find a whole lot. website addys would help.

[300ex13]

the biggest i kno of is the 330 but there might be one bigger

[underpowered]

had a gt thunder 350 big bore kit in my old 300ex. 330 is the biggest you can go without machining the bottom cases. As far as stroking i'm not sure how much more you can go.

[bradley300]

the biggest ive seen was a curtis sparks built 416 cc . i know tc sells a 405 kit

[300ex73]

I've heard of Sparks doing 300 motors all the way up to around a 425/426.

[bwamos]

350x motor bored and stroked to a 468cc. That's the meanest 250x/300ex I've seen.. lol

[300ex_#387]

xr 600 in a 300ex :D now thats the biggest

[rm25x]

Originally posted by bradley300
the biggest ive seen was a curtis sparks built 416 cc . i know tc sells a 405 kit
Who's TC? Over 400 was my goal. I have seen the 392 bore/stroke kits, and didn't know if that was the biggest.

[honda250xrider]

I have a 406 stroker right now, and let me tell you this thing has some serious power, but i would not do this again with over 3 grand in the motor i could of already went out and bought a 450r and could of had alot more potential.

[bradley300]

Originally posted by rm25x
Who's TC? Over 400 was my goal. I have seen the 392 bore/stroke kits, and didn't know if that was the biggest.

TC racing, they dont have a website, so look in the mags for a phone number. there one of the big dogs

[rm25x]

Originally posted by honda250xrider
I have a 406 stroker right now, and let me tell you this thing has some serious power, but i would not do this again with over 3 grand in the motor i could of already went out and bought a 450r and could of had alot more potential.
yeah I know, thats my other thinking.....

[ghak99]

I have GT Thunders's 380 kit in mine right now. You can go all the way to 426-428cc's, but they do not run much harder than the 370-380cc motors and have a much shorter life span. The 406-410 kits run hard but the piston is getting large enough that reliability drops on them too. The 370-380 range seems to be the most reliable and have a balanced enough motor to make strong torque while still being very quick.

One thing to consider is the type of racing you do and the type of rider you are. Many people do not like their big stroker motors after building them. They need a certain type of rider and gear ratio to used them correctly. I built mine after knowing it was "my type of motor".

I suggest giving Laz at GT Thunder a call even if you don't go with his products you might learn a little.

;)

[dork]

listen to what ghak99 says about building a big motor, if you start going huge and stroking them, they lose some of their revviness and become more of a tractor. FST sells a 380 bore kit (no stroke), you just have to machine the cases and install a bigger rod. dunlap says the 428 kits he used to sell didn't rev out as well as the 380 kit for the 300ex or make enough more power to make them worthwhile after the 400ex came out. TC used to run his 425 motor in the open TT class and was competitve with banshees etc. they cost some money to build, but if you like your machine them it may be worth it to you. whats nice is you can get the extra power and still have reverse and electric start in a smaller chassis thats easier to ride, im my opinion.

[rm25x]

Yeah its nice being able to really throw the machine around. Just could use a little more oomph. I was looking at the 330 bore kits for $250. Might be what I need, added with a good cam and port job. I don't want it to rev like a pig.