416 Curtis sparks big bore kit. any tips reliability issues gncc bike

[400exrich]

Hey I look up a Curtis sparks 416 bore kit and I heard that it revs quicker than a 440 and the kit plows away the 440s and 450s i also plan on racing gncc with it and if I get the 416 kit in gunna get a curtis sparks rev box and a fcr carb I was wondering also if there is any reliably issues with the kit I'm getting a upgraded oil tank and the oil cooler trick that I found on this site thanks

[Longdong]

What all comes with the kit?

[Stickman400]

It's just common knowledge that a 416 revs faster than a 440 since the piston itself is lighter. They won't blow a 450R out of the water unless they are bone stock or almost bone stock and you are pretty built, even then it would be neck and neck. Just because Curtis Sparks makes it doesn't mean it's better than everything else that's exactly the same spec. wise. Don't get me wrong, they make good stuff, but they act like their stuff is made of gold compared to everything else price wise. The rev box isn't gunna be anything special either. The carb. may be worth it though just because it's an FCR carb., never heard of any issues with them. You could prolly pick up a used YFZ or 450R FCR for less cash and have the same outcome though. Just my .02 cents.

[ish416]

If you go with Curtis Sparks, you are paying extra for a name and nothing more.

You could go with a JE or Wiseco 87mm piston with 11:1 compression, Honda XR400R OEM or Cometic MLS gaskets, have someone install some heavy duty head studs, install a stage 2 hotcam, port the head, and buy either a YFZ450 FCR carb or make your life much easier and just get an 04-05 450R carb and a CRF450 timing chain.

You will have the same or better performance and spend much less than what Sparks would charge you for equal or lesser components.

Also, the CDI doesn't do anything but let your valves float. Every 400EX with the exception of a fully built drag quad will stop making power way, way before even the stock limiter will kick in. Adding more rpm to these engines doesn't make sense. Don't waste your time or money on one. If you feel the need to however, just find an XR250 CDI as that is what nearly all of the aftermarket ones are.

The 416's are very solid and when built properly using good components, the engine will last as long as any stock EX will. The keys to reliability are the heavy duty head studs, good gaskets and the CRF timing chain.

I would highly recommend putting this money into suspension and comfort mods than an engine overhaul. Unless of course your engine needs freshened up.

[ben300]

I would highly recommend putting this money into suspension and comfort mods than an engine overhaul. Unless of course your engine needs freshened up.


as said before,and as many will say it again


GNCC is about handling and endurance, not crazy HP. Go race a few races, get the feel for it, find out if you actually like it, before you do a total motor build. and unless you plan on being totally commited to the sport class, dont go hog wild with a 400 motor build, cuase you'll just want to upgrade to a 450 before to long and you'll never recoup your money spent.

[Blodg]

Ish, that post was spot-on and almost word-for-word what I would have recommended.

[DragonGunner]

If you build your engine ask Sparks if the powerband programming in the cdi is different than a stocker, if it is then its like the WB ones like I have that actually work day and night better than stock, would be worth the money. The good cdi do more than just add more rpm, some guys I think bought cheap ones and they weren't any different and assume all cdi must be junk. Doug Eichner didn't win all those World Four Stroke Championships on a stock cdi in his Duncan 440.

[400exrich]

as said before,and as many will say it again


GNCC is about handling and endurance, not crazy HP. Go race a few races, get the feel for it, find out if you actually like it, before you do a total motor build. and unless you plan on being totally commited to the sport class, dont go hog wild with a 400 motor build, cuase you'll just want to upgrade to a 450 before to long and you'll never recoup your money spent.

thanks and ya i know i want to get into races and get known i want to race professionally

[Longdong]

thanks and ya i know i want to get into races and get known i want to race professionally

It's good you have a goal. I just hope your parent or you have the money! Good luck