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jsracing2
11-23-2010, 06:25 PM
What is the best rev box. I just got a 417ex, cams, and some head work and it seems slower than my stock one with a 1000 extra rpm. Gearing may have some to do with it, but ???? What is the best rev box/cdi to get?
honda400ex2003
11-23-2010, 06:29 PM
your stock one is the best one to get. theres no way your 416 is making power up far enough to need the extra 1000 rpm. either figure out a better gearing setup to make better use of the power or find out why it doesnt run the way you want it to do. steve
smoke tractor1
11-23-2010, 06:33 PM
XR250R stock box,You don't gain as much power with 1000rpm as the extra stress you put on the valvetrain.But to answer your question the xr dirtbike cdi is what the aftermarket cdi's are base off mainly,Xr OEM honda is probably much more reliable if you have to go that way! BIG RED WINGS!
3400ben
11-23-2010, 06:55 PM
Originally posted by honda400ex2003
your stock one is the best one to get. theres no way your 416 is making power up far enough to need the extra 1000 rpm. either figure out a better gearing setup to make better use of the power or find out why it doesnt run the way you want it to do. steve
X2
Honda5
11-23-2010, 07:05 PM
I had great luck with the procom and bad luck with the white bros. (they were hard to start and i think they were just xr400) you will notice a nice improvement with the cams headwork and a good exhaust.
SpasticR450
11-23-2010, 07:08 PM
XR250 same. Your better off spending the money on a dyno run to see that your peak power drops off before your stock red line. There is some Boxes like big gun that clame advancing timing that adds 2hp but i seen a dyno and it added less than 1.
honda400ex2003
11-23-2010, 07:45 PM
if indeed you want to use it to advance the timing, just get a sparks 6 degree key or a 4 or 3 degree from wheelie to advance it the amount you would like to run. steve
Honda5
11-23-2010, 08:00 PM
Try this. Buy one and try it for a few rides and then put the stock one back in for a ride and I'll bet you go back to it. They are cheap (I probably have a few left from when we raced them) and if you don't like it sell it. It is not only about peak hp it is nice at the end of a long straight not to have to shift one more time for the last ten feet before brakeing. There is a reason that racers use them. Watch out for the advance keys they are weak and on a hard backfire they will shear off. Had that happen a few times on the 13:1
motors.
SpasticR450
11-23-2010, 08:15 PM
Originally posted by Honda5
Try this. Buy one and try it for a few rides and then put the stock one back in for a ride and I'll bet you go back to it. They are cheap (I probably have a few left from when we raced them) and if you don't like it sell it. It is not only about peak hp it is nice at the end of a long straight not to have to shift one more time for the last ten feet before brakeing. There is a reason that racers use them. Watch out for the advance keys they are weak and on a hard backfire they will shear off. Had that happen a few times on the 13:1
motors.

13:1 comp built engine with a timing key? You do no they are only ment for stock engines with exhaust/filter up grades right?
spark plug
11-23-2010, 08:25 PM
From my searches and experiences, rev boxes are all made by a few companies and sold to others who put there name on them. Stock is the way to go. The "White Bros" one i had was a big headache and didn;t really feel any gains over stock.
.02
Honda5
11-23-2010, 08:27 PM
we did anything we could for power that was also cutting the head .040 if we could have found a cdi that went 2000 over we would have tried it. Just because you can doesn't mean you have to.
Wheelie
11-23-2010, 08:31 PM
Rev boxes are a waste of money, a stock EX quits making power at 7k rpm, the stock rev limit is 9100. Read my sig, it's the one mod I don't have and for a good reason.

A timing key will give much better gains, be more reliable and less than 1/3 of the cost of a rev box.


If any flywheel key shears, it's due to poor installation, not the key. The key doesn't hold the flywheel, it's simply there to align the flywheel for installation. The taper seat of the flywheel/crankshaft is what seats and holds the flywheel in place--NOT the key.

FWIW--I'm running 11.3:1 compression with a 4 degree advance key and stock head studs. 2 years this way, 5 years on the motor itself. Runs very strong and doesn't use any oil. Zero issues.
SpasticR450
11-23-2010, 08:34 PM
Originally posted by Wheelie
Rev boxes are a waste of money, a stock EX quits making power at 7k rpm, the stock rev limit is 9100. Read my sig, it's the one mod I don't have and for a good reason.

A timing key will give much better gains, be more reliable and less than 1/3 of the cost of a rev box.


If any flywheel key shears, it's due to poor installation, not the key. The key doesn't hold the flywheel, it's simply there to align the flywheel for installation. The taper seat of the flywheel/crankshaft is what seats and holds the flywheel in place--NOT the key.

FWIW--I'm running 11.3:1 compression with a 4 degree advance key and stock head studs. 2 years this way, 5 years on the motor itself. Runs very strong and doesn't use any oil. Zero issues.

Keys are still made for stock engines. When u run them on engines with mods heat can become a prob.
honda400ex2003
11-23-2010, 08:38 PM
5 or 10 degrees is nothing really imo. thats all i ever ran hotter than not running it. i never really run over 200 F on oil temps unless i am really riding hard. that is 50 less than really needing to worry about anything becoming a problem. I run both the 6 and 3 in mine with great results on my 416. steve
rinconrider
11-24-2010, 09:33 AM
I agree with the key and stock box also. after trying out a couple i went back to the stocker. it is just like the monster coil, that is a waste of money too.
Muddytoy07
11-24-2010, 05:29 PM
I have a BIG GUN Over Rev and I really like it for the kinda riding that I do, I don't race but its nice not to have to make that one last shift before hitting the turn, I am also looking at running a 3 degree key with it in the next few weeks after I get the wife's quad all taken care of.
SpasticR450
11-24-2010, 11:02 PM
Originally posted by honda400ex2003
5 or 10 degrees is nothing really imo. thats all i ever ran hotter than not running it. i never really run over 200 F on oil temps unless i am really riding hard. that is 50 less than really needing to worry about anything becoming a problem. I run both the 6 and 3 in mine with great results on my 416. steve

Well another thing is I think the key can make you need race gas before a normal engine with the same mods other than the key.
Wheelie
11-25-2010, 08:42 AM
Originally posted by SpasticR450
Well another thing is I think the key can make you need race gas before a normal engine with the same mods other than the key.

This is correct. The gains are well worth it for those who don't mind paying a little extra for high octane fuel.

A SPAL fan helps with the extra heat, as does E-85 for those who have access to it.